A sham controlled study of repetitive transcranial magnetic stimulation for posttraumatic stress disorder

A potential target for noninvasive neuromodulation of PTSD symptoms derived from focal brain lesions in veterans

Neuromodulation trials for the treatment of posttraumatic stress disorder (PTSD) have yielded mixed results, and the optimal neuroanatomical target remains unclear. Here we analyzed three datasets to study brain circuitry causally linked to PTSD in military veterans. In veterans with penetrating traumatic brain injury, lesion locations that reduced probability of PTSD were preferentially connected to a circuit including the medial prefrontal cortex, amygdala and anterolateral temporal lobe. In veterans without lesions, PTSD was specifically associated with increased connectivity within this circuit. Reduced functional connectivity within this circuit after transcranial magnetic stimulation correlated with symptom reduction, even though the circuit was not directly targeted. This lesion-based 'PTSD circuit' may serve as a target for clinical trials of neuromodulation in veterans with PTSD.

Transcranial magnetic stimulation for obsessive-compulsive disorder and post-traumatic stress disorder: A comprehensive systematic review and analysis of therapeutic benefits, cortical targets, and psychopathophysiological mechanisms

Transcranial magnetic stimulation (TMS) is a safe non-invasive treatment technique. We systematically reviewed randomised controlled trials (RCTs) applying TMS in obsessive compulsive disorder (OCD) and post-traumatic stress disorder (PTSD) to analyse its therapeutic benefits and explore the relationship between cortical target and psychopathophysiology. We included 47 randomised controlled trials (35 for OCD) and found a 22.7 % symptom improvement for OCD and 29.4 % for PTSD. Eight cortical targets were investigated for OCD and four for PTSD, yielding similar results. Bilateral dlPFC-TMS exhibited the greatest symptom change (32.3 % for OCD, N = 4 studies; 35.7 % for PTSD, N = 1 studies), followed by right dlPFC-TMS (24.4 % for OCD, N = 8; 26.7 % for PTSD, N = 10), and left dlPFC-TMS (22.9 % for OCD, N = 6; 23.1 % for PTSD, N = 1). mPFC-TMS showed promising results, although evidence is limited (N = 2 studies each for OCD and PTSD) and findings for PTSD were conflicting. Despite clinical improvement, reviewed reports lacked a consistent and solid rationale for cortical target selection, revealing a gap in TMS research that complicates the interpretation of findings and hinders TMS development and optimisation. Future research should adopt a hypothesis-driven approach rather than relying solely on correlations from imaging studies, integrating neurobiological processes with affective, behavioural, and cognitive states, thereby doing justice to the complexity of human experience and mental illness.

Beyond Pharmacology: A Narrative Review of Alternative Therapies for Anxiety Disorders

BACKGROUND

Anxiety disorders significantly reduce patients' quality of life. Current pharmacological treatments, primarily benzodiazepines and antidepressants, are associated with numerous side effects. Consequently, there is a continual search for alternative methods to traditional therapies that are less burdensome for patients and broaden their therapeutic options. Our objective was to determine the role of selected alternative methods in the treatment of anxiety disorders.

METHODS

In this review, we examined recent evidence on alternative treatments for anxiety disorders, including physical activity, mindfulness, virtual reality (VR) technology, biofeedback, herbal remedies, transcranial magnetic stimulation (TMS), cryotherapy, hyperbaric therapy, vagus nerve stimulation (VNS), 3,4-methylenedioxymethamphetamine (MDMA), electroconvulsive therapy (ECT), and eye movement desensitization and reprocessing (EMDR) therapy. For this purpose we reviewed PubMed and after initial search, we excluded works unrelated to our aim, non-orginal data and animal studies. We conducted second search to cover all minor methods.

RESULTS

We included 116 studies, which data is presented in Tables. We have investigated which methods can support treatment and which can be used as a stand-alone treatment. We assessed the risks to benefits of using alternative treatments.

CONCLUSION

Alternative treatments significantly expand the options available to patients and clinicians, with many serving as adjuncts to traditional therapies. Among the methods presented, mindfulness has the most significant therapeutic potential.

Repetitive transcranial magnetic stimulation for post-traumatic stress disorder in adults

BACKGROUND

The estimated lifetime prevalence of post-traumatic stress disorder (PTSD) in adults worldwide has been estimated at 3.9%. PTSD appears to contribute to alterations in neuronal network connectivity patterns. Current pharmacological and psychotherapeutic treatments for PTSD are associated with inadequate symptom improvement and high dropout rates. Repetitive transcranial magnetic stimulation (rTMS), a non-invasive therapy involving induction of electrical currents in cortical brain tissue, may be an important treatment option for PTSD to improve remission rates and for people who cannot tolerate existing treatments.

OBJECTIVES

To assess the effects of repetitive transcranial magnetic stimulation (rTMS) on post-traumatic stress disorder (PTSD) in adults.

SEARCH METHODS

We searched the Cochrane Common Mental Disorders Controlled Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two clinical trials registers. We checked reference lists of relevant articles. The most recent search was January 2023.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) assessing the efficacy and safety of rTMS versus sham rTMS for PTSD in adults from any treatment setting, including veterans. Eligible trials employed at least five rTMS treatment sessions with both active and sham conditions. We included trials with combination interventions, where a pharmacological agent or psychotherapy was combined with rTMS for both intervention and control groups. We included studies meeting the above criteria regardless of whether they reported any of our outcomes of interest.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias in accordance with Cochrane standards. Primary outcomes were PTSD severity immediately after treatment and serious adverse events during active treatment. Secondary outcomes were PTSD remission, PTSD response, PTSD severity at two follow-up time points after treatment, dropouts, and depression and anxiety severity immediately after treatment.

MAIN RESULTS

We included 13 RCTs in the review (12 published; 1 unpublished dissertation), with 577 participants. Eight studies included stand-alone rTMS treatment, four combined rTMS with an evidence-based psychotherapeutic treatment, and one investigated rTMS as an adjunctive to treatment-as-usual. Five studies were conducted in the USA, and some predominantly included white, male veterans. Active rTMS probably makes little to no difference to PTSD severity immediately following treatment (standardized mean difference (SMD) -0.14, 95% confidence interval (CI) -0.54 to 0.27; 3 studies, 99 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision (sample size insufficient to detect a difference of medium effect size). We deemed one study as having a low risk of bias and the remaining two as having 'some concerns' for risk of bias. A sensitivity analysis of change-from-baseline scores enabled inclusion of a greater number of studies (6 studies, 252 participants). This analysis yielded a similar outcome to our main analysis but also indicated significant heterogeneity in efficacy across studies, including two studies with a high risk of bias. Reported rates of serious adverse events were low, with seven reported (active rTMS: 6; sham rTMS: 1). The evidence is very uncertain about the effect of active rTMS on serious adverse events (odds ratio (OR) 5.26, 95% CI 0.26 to 107.81; 5 studies, 251 participants; very low-certainty evidence [Active rTMS: 23/1000, sham rTMS: 4/1000]). We downgraded the evidence by one level for risk of bias and two levels for imprecision. We rated four of five studies as having a high risk of bias, and the fifth as 'some concerns' for bias. We were unable to assess PTSD remission immediately after treatment as none of the included studies reported this outcome.

AUTHORS' CONCLUSIONS

Based on moderate-certainty evidence, our review suggests that active rTMS probably makes little to no difference to PTSD severity immediately following treatment compared to sham stimulation. However, significant heterogeneity in efficacy was detected when we included a larger number of studies in sensitivity analysis. We observed considerable variety in participant and protocol characteristics across studies included in this review. For example, studies tended to be weighted towards inclusion of either male veterans or female civilians. Studies varied greatly in terms of the proportion of the sample with comorbid depression. Study protocols differed in treatment design and stimulation parameters (e.g. session number/duration, treatment course length, stimulation intensity/frequency, location of stimulation). These differences may affect efficacy, particularly when considering interactions with participant factors. Reported rates of serious adverse events were very low (< 1%) across active and sham conditions. It is uncertain whether rTMS increases the risk of serious adverse event occurrence, as our certainty of evidence was very low. Studies frequently lacked clear definitions for serious adverse events, as well as detail on tracking/assessment of data and information on the safety population. Increased reporting on these elements would likely aid the advancement of both research and clinical recommendations of rTMS for PTSD. Currently, there is insufficient evidence to meta-analyze PTSD remission, PTSD treatment response, and PTSD severity at different periods post-treatment. Further research into these outcomes could inform the clinical use of rTMS. Additionally, the relatively large contribution of data from trials that focused on white male veterans may limit the generalizability of our conclusions. This could be addressed by prioritizing recruitment of more diverse participant samples.

Efficacy of MRI-guided rTMS for post-traumatic stress disorder by modulating amygdala activity: study protocol for a randomised controlled trial

INTRODUCTION

Post-traumatic stress disorder (PTSD) is a prevalent and severe psychiatric disorder. Repetitive transcranial magnetic stimulation (rTMS) targeting the dorsolateral prefrontal cortex provides limited relief for symptoms of PTSD. This study will be conducted to validate the efficacy of MRI-guided rTMS in targeting the sites most closely associated with the amygdala for patients with PTSD. We hypothesise that the intervention will improve clinical symptoms by decreasing amygdala activity in patients.

METHODS AND ANALYSIS

A randomised, double-blind, sham-controlled trial will be conducted. Forty-eight eligible patients with PTSD will be randomly assigned to receive either active or sham MRI-guided rTMS for 10 consecutive days after the initial MRI scans. MRI scans will be recollected at the end of the intervention. Clinical assessments will be performed at baseline, treatment day 5, treatment day 10, and 2 weeks, 4 weeks, 8 weeks after completion of the intervention to monitor changes in clinical symptoms. The primary assessment outcome is the change in PTSD symptoms between baseline and treatment day 10, as measured by the PTSD Checklist for DSM-5. Repeated measures analysis of variance will be performed using statistical software SPSS V.26.0. The significance level will be set at 0.05.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Ethics Committee of Xijing Hospital in Xi'an, China (KY20222176-X-1), and the trial has been registered on ClinicalTrials.gov. The findings of this trial will be disseminated at academic conferences or published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT05544110.

Efficacy and acceptability of noninvasive brain stimulation for treating posttraumatic stress disorder symptoms: A network meta-analysis of randomized controlled trials

INTRODUCTION

Despite its high lifetime prevalence rate and the elevated disability caused by posttraumatic stress disorder (PTSD), treatments exhibit modest efficacy. In consideration of the abnormal connectivity between the dorsolateral prefrontal cortex (DLPFC) and amygdala in PTSD, several randomized controlled trials (RCTs) addressing the efficacy of different noninvasive brain stimulation (NIBS) modalities for PTSD management have been undertaken. However, previous RCTs have reported inconsistent results. The current network meta-analysis (NMA) aimed to compare the efficacy and acceptability of various NIBS protocols in PTSD management.

METHODS

We systematically searched ClinicalKey, Cochrane Central Register of Controlled Trials, Embase, ProQuest, PubMed, ScienceDirect, Web of Science, and ClinicalTrials.gov to identify relevant RCTs. The targeted RCTs was those comparing the efficacy of NIBS interventions, such as transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and transcutaneous cervical vagal nerve stimulation, in patients with PTSD. The NMA was conducted using a frequentist model. The primary outcomes were changes in the overall severity of PTSD and acceptability (to be specific, rates of dropouts for any reason).

RESULTS

We identified 14 RCTs that enrolled 686 participants. The NMA demonstrated that among the investigated NIBS types, high-frequency rTMS over bilateral DLPFCs was associated with the greatest reduction in overall PTSD severity. Further, in comparison with the sham controls, excitatory stimulation over the right DLPFC with/without excitatory stimulation over left DLPFC were associated with significant reductions in PTSD-related symptoms, including depression and anxiety symptoms, and overall PTSD severity.

CONCLUSIONS

This NMA demonstrated that excitatory stimulation over the right DLPFC with or without excitatory stimulation over left DLPFC were associated with significant reductions in PTSD-related symptoms.

TRIAL REGISTRATION

PROSPERO CRD42023391562.

Critically Assessing the Unanswered Questions of How, Where, and When to Induce Plasticity in the Posttraumatic Stress Disorder Network With Transcranial Magnetic Stimulation

Extinction of traumatic memory, a primary treatment approach (termed exposure therapy) in posttraumatic stress disorder (PTSD), occurs through relearning and may be subserved at the molecular level by long-term potentiation of relevant circuits. In parallel, repetitive transcranial magnetic stimulation (TMS) is thought to work through long-term potentiation-like mechanisms and may provide a novel, safe, and effective treatment for PTSD. In a recent failed randomized controlled trial we emphasized the necessity of correctly identifying cortical targets, the directionality of TMS protocols, and the role of memory activation. Here, we provide a systematic review of TMS for PTSD to further identify how, where, and when TMS treatment should be delivered to alleviate PTSD symptoms. We conducted a systematic review of the literature by searching for repetitive TMS clinical trials involving patients with PTSD and outcomes. We searched MEDLINE through October 25, 2023, for "TMS and PTSD" and "transcranial magnetic stimulation and posttraumatic stress disorder." Thirty-one publications met our inclusion criteria (k = 17 randomized controlled trials, k = 14 open label). Randomized controlled trial protocols were varied in terms of TMS protocols, cortical TMS targets, and memory activation protocols. There was no clear superiority of low-frequency (k = 5) versus high-frequency (k = 6) protocols or by stimulation location. Memory provocation or exposure protocols (k = 7) appear to enhance response. Overall, TMS appears to be effective in treating PTSD symptoms across a variety of TMS frequencies, hemispheric target differences, and exposure protocols. Disparate protocols may be conceptually harmonized when viewed as potentiating proposed anxiolytic networks or suppressing anxiogenic networks.

Explore the durability of repetitive transcranial magnetic stimulation in treating post-traumatic stress disorder: An updated systematic review and meta-analysis

The objective was to synthesize results from studies that assessed symptom relief after repetitive transcranial magnetic stimulation (rTMS) treatment for post-traumatic stress disorder (PTSD) and investigate the long-term effectiveness of rTMS for treating PTSD. We searched multiple databases for relevant randomized controlled trials of rTMS for PTSD treatment up to 1 January 2023. Two researchers evaluated the studies and focused on the CAPS and PCL as outcome indicators. We used STATA17 SE software for the data analysis. Eight articles involving 309 PTSD patients were analysed in a meta-analysis, which found that rTMS had a significant and large effect on reducing core post-traumatic symptoms [Hedges'g = 1.75, 95% CI (1.18, 2.33)]. Both low and high-frequency rTMS also significantly reduced symptoms, with the latter having a greater effect. rTMS was shown to have a long-term effect on PTSD, with all three subgroup analyses demonstrating significant results. Interestingly, no significant difference in symptom relief was found between the follow-up and completion of treatments [Hedges'g = 0.01, 95% CI (-0.30, 0.33)], suggesting that the treatment effect of rTMS is stable. The meta-analysis provides strong evidence that rTMS is effective in reducing the severity and symptoms of PTSD in patients, and follow-up studies confirm its long-term stability.

Effects of intermittent theta-burst transcranial magnetic stimulation on post-traumatic stress disorder symptoms: A randomized controlled trial

Post-traumatic stress disorder (PTSD) is a prevalent and debilitating illness, which can be alleviated by transcranial magnetic stimulation (TMS). Intermittent theta burst stimulation (iTBS), a newer form of repetitive transcranial magnetic stimulation (rTMS), offers the advantage of shorter treatment sessions compared to the standard 10 Hz rTMS treatment. In order to compare the two forms of TMS, we enrolled 75 participants aged between 18 and 55 years who presented with (PCL-C) scale score of at least 50. Participants were randomly assigned to groups in a ratio of 1:1:1, receiving either 10 Hz rTMS, iTBS, or sham-controlled iTBS. Participants in the two treatment groups underwent 15 therapies which consisted of 1800 pulses and targeted the right dorsolateral prefrontal cortex (DLPFC). The main outcomes included changes in scores on the PCL-C and the Post-Traumatic Growth Inventory (PTGI). After intervention, the PCL-C and PTGI scores in iTBS and rTMS groups were significantly different from those in sham-controlled iTBS group. No significant differences in PCL-C and PTGI were found between the two active treatment groups. ITBS, with a shorter treatment duration, can effectively improve the symptoms of PTSD, with no significant difference in effect from that of rTMS. Future studies need to further elucidate the mechanisms, optimize the parameters and investigate the therapeutic potential and efficacy of iTBS in PTSD.

P3a amplitude to trauma-related stimuli reduced after successful trauma-focused PTSD treatment

An elevated P3a amplitude to trauma-related stimuli is strongly associated with posttraumatic stress disorder (PTSD), yet little is known about whether this response to trauma-related stimuli is affected by treatment that decreases PTSD symptoms. As an analysis of secondary outcome measures from a randomized controlled trial, we investigated the latency and amplitude changes of the P3a in responses in a three-condition oddball visual task that included trauma-related (combat scenes) and trauma-unrelated (threatening animals) distractors. Fifty-five U.S. veterans diagnosed with combat-related PTSD were randomized to receive either active or sham repetitive transcranial magnetic stimulation (rTMS). All received cognitive processing therapy, CPT+A, which requires a written account of the index trauma. They were tested before and 6 months after protocol completion. P3a amplitude and response time decreases were driven largely by the changes in the responses to the trauma-related stimuli, and this decrease correlated to the decrease in PTSD symptoms. The amplitude changes were greater in those who received rTMS + CPT than in those who received sham rTMS + CPT, suggesting that rTMS plays beneficial role in reducing arousal and threat bias, which may allow for more effective engagement in trauma-focused PTSD treatment.

Personalized repetitive transcranial magnetic stimulation (prtms®) for post-traumatic stress disorder (ptsd) in military combat veterans

Emerging data suggest that post-traumatic stress disorder (PTSD) arises from disrupted brain default mode network (DMN) activity manifested by dysregulated encephalogram (EEG) alpha oscillations. Hence, we pursued the treatment of combat veterans with PTSD (n = 185) using an expanded form of repetitive transcranial magnetic stimulation (rTMS) termed personalized-rTMS (PrTMS). In this treatment methodology spectral EEG based guidance is used to iteratively optimize symptom resolution via (1) stimulation of multiple motor sensory and frontal cortical sites at reduced power, and (2) adjustments of cortical treatment loci and stimulus frequency during treatment progression based on a proprietary frequency algorithm (PeakLogic, Inc. San Diego) identifying stimulation frequency in the DMN elements of the alpha oscillatory band. Following 4 - 6 weeks of PrTMS® therapy in addition to routine PTSD therapy, veterans exhibited significant clinical improvement accompanied by increased cortical alpha center frequency and alpha oscillatory synchronization. Full resolution of PTSD symptoms was attained in over 50% of patients. These data support DMN involvement in PTSD pathophysiology and suggest a role in therapeutic outcomes. Prospective, sham controlled PrTMS® trials may be warranted to validate our clinical findings and to examine the contribution of DMN targeting for novel preventive, diagnostic, and therapeutic strategies tailored to the unique needs of individual patients with both combat and non-combat PTSD.

Effectiveness of repetitive transcranial magnetic stimulation combined with a brief exposure procedure for post-stroke posttraumatic stress disorder

The incidence of posttraumatic stress disorder (PTSD) following stroke ranges from 6.5 % to 25 %. Presently few studies have focused on its treatment. Repetitive transcranial magnetic stimulation (rTMS) is often applied as a rehabilitation method after stroke, and it also represents a novel approach to PTSD. The aim of this study was to explore the effect of rTMS (or combined with a brief stroke re-exposure) on treating post-stroke PTSD. Sixty participants with post-stroke PTSD were randomly assigned into three groups (rTMS + brief exposure group, TMS + BE; rTMS alone group, TMS; sham treatment group, ST) and received 10 sessions of treatment accordingly over two weeks. Changes in PTSD symptoms (Impact of Event Scale-Revised, IES-R) were evaluated at pre-treatment (T1), the end of the first (T2), and the end of the second treatment week (T3). At the three-month follow-up (T4), a PTSD interview and IES-R assessment were given. Results showed that from T1 to T3, IES-R (and its intrusion subscale) scores of TMS + BE group and TMS group were significantly lower than the ST group, and the effect remained at three-month follow-up. The treatment effect was comparable between TMS + BE group and TMS group at T3, however, it was better for TMS + BE group than TMS group at T2, indicating a brief exposure promotes the effect of rTMS. At follow-up, the rates of PTSD were lower in TMS + BE group and TMS group than ST group. In conclusion, rTMS can effectively treat post-stroke PTSD and the effects may be accelerated by combining a brief exposure procedure. TRIAL REGISTRATION: Chinese Clinical Trial Registry, identifier: ChiCTR2100043444.

Cingulate-Prefrontal Connectivity During Dynamic Cognitive Control Mediates Association Between p Factor and Adaptive Functioning in a Transdiagnostic Pediatric Sample

BACKGROUND

Covariation among psychiatric symptoms is being actively pursued for transdiagnostic dimensions of psychopathology with predictive utility. A superordinate dimension, the p factor, reflects overall psychopathology burden and has support from genetic and neuroimaging correlates. However, the neurocognitive correlates that link an elevated p factor to maladaptive outcomes are unknown. We tested the mediating potential of dynamic adjustments in cognitive control rooted in functional connections anchored by the dorsal anterior cingulate cortex (dACC) in a transdiagnostic pediatric sample.

METHODS

A multiple mediation model tested the association between the p factor (derived by principal component analysis of Child Behavior Checklist syndrome scales) and outcome measured with the Vineland Adaptive Behavior Scale-II in 89 children ages 8 to 13 years (23 female) with a variety of primary neurodevelopmental diagnoses who underwent functional magnetic resonance imaging during a socioaffective Stroop-like task with eye gaze as distractor. Mediators included functional connectivity of frontoparietal- and salience network-affiliated dACC seeds during conflict adaptation.

RESULTS

Higher p factor scores were related to worse adaptive functioning. This effect was partially mediated by conflict adaptation-dependent functional connectivity between the frontoparietal network-affiliated dACC seed and the right dorsolateral prefrontal cortex. Post hoc follow-up indicated that the p factor was related to all Vineland Adaptive Behaviors Scale-II domains; the association was strongest for socialization followed by daily living skills and then communication. Mediation results remained significant for socialization only.

CONCLUSIONS

Higher psychopathology burden was associated with worse adaptive functioning in early adolescence. This association was mediated by weaker dACC-dorsolateral prefrontal cortex functional connectivity underlying modulation of cognitive control in response to contextual contingencies. Our results contribute to the identification of transdiagnostic and developmentally relevant neurocognitive endophenotypes of psychopathology.

Effects of transcranial direct current stimulation (tDCS) in "Kiss nightclub fire" patients with post-traumatic stress disorder (PTSD): A phase II clinical trial

Objective

Considered the second biggest tragedy with fatal victims caused by fire, the Kiss nightclub fire tragedy that occurred in the interior of southern Brazil brought several problems to survivors. It is reported that 30-40% of victims of disasters can develop post-traumatic stress disorder. Application of repetitive transcranial magnetic stimulation has shown promising results in the treatment of post-traumatic stress disorder. Transcranial direct current stimulation similar to repetitive transcranial magnetic stimulation, a neuromodulation technique, has shown promise in treatment of neuropsychiatric disorders.

Method

A clinical trial was conducted from March 2015 to July 2016 in "KISS nightclub fire" disaster patients diagnosed with post-traumatic stress disorder without complete remission of symptoms, over 18 years, and who maintained pharmacological treatment. Treatment was given using electrodes as cathode (right dorsolateral prefrontal cortex) and anode (contralateral deltoid muscle); a current of 2 mA was used for 25 cm² area (0.08 mA/cm² current density); 30 min once a day for 10 days continuously. Patients assessed pre- and post-intervention, 30 days' and 90 days' post-intervention. Post-Traumatic Stress Disorder Checklist, Civilian version, Montreal Cognitive Assessment, and Hamilton Depression and Anxiety Rating Scale were used.

Results

One hundred forty-five subjects were screened and eight analyzed; 87.5% were female; 30.88 ± 7.74 years were of mean age. Post-intervention results: no cognitive impairment (Montreal Cognitive Assessment), 60% reduction in Hamilton Depression Rating Scale (moderate depression turns normal) (p < 0.001), 54.39% Hamilton Anxiety Rating Scale reduction (moderate-to-severe symptoms turn into mild symptoms) (p < 0.001), and 20% Post-Traumatic Stress Disorder Checklist, Civilian version scale decrease (high severity post-traumatic stress disorder symptoms turn moderate to moderately high severity) (p < 0.001). Post-traumatic stress disorder symptoms improvement was maintained 30-days post-intervention (Post-Traumatic Stress Disorder Checklist, Civilian version, p = 0.025) and improvement in symptoms of depression (Hamilton Depression Rating Scale, p = 0.006) and anxiety (Hamilton Anxiety Rating Scale, p = 0.028) in 90 days post-intervention.

Conclusion

Despite decrease over time, improvement in post-traumatic stress disorder, depression and anxiety symptoms was maintained throughout the first month after treatment. Transcranial direct current stimulation adjuvant can be an alternative treatment to refractory post-traumatic stress disorder, either as monotherapy or as treatment enhancement strategy. They can also be an option for patients who do not want or do not tolerate pharmacological management.

Contemporary Approaches Toward Neuromodulation of Fear Extinction and Its Underlying Neural Circuits

Neuroscience and neuroimaging research have now identified brain nodes that are involved in the acquisition, storage, and expression of conditioned fear and its extinction. These brain regions include the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), amygdala, insular cortex, and hippocampus. Psychiatric neuroimaging research shows that functional dysregulation of these brain regions might contribute to the etiology and symptomatology of various psychopathologies, including anxiety disorders and post traumatic stress disorder (PTSD) (Barad et al. Biol Psychiatry 60:322-328, 2006; Greco and Liberzon Neuropsychopharmacology 41:320-334, 2015; Milad et al. Biol Psychiatry 62:1191-1194, 2007a, Biol Psychiatry 62:446-454, b; Maren and Quirk Nat Rev Neurosci 5:844-852, 2004; Milad and Quirk Annu Rev Psychol 63:129, 2012; Phelps et al. Neuron 43:897-905, 2004; Shin and Liberzon Neuropsychopharmacology 35:169-191, 2009). Combined, these findings indicate that targeting the activation of these nodes and modulating their functional interactions might offer an opportunity to further our understanding of how fear and threat responses are formed and regulated in the human brain, which could lead to enhancing the efficacy of current treatments or creating novel treatments for PTSD and other psychiatric disorders (Marin et al. Depress Anxiety 31:269-278, 2014; Milad et al. Behav Res Ther 62:17-23, 2014). Device-based neuromodulation techniques provide a promising means for directly changing or regulating activity in the fear extinction network by targeting functionally connected brain regions via stimulation patterns (Raij et al. Biol Psychiatry 84:129-137, 2018; Marković et al. Front Hum Neurosci 15:138, 2021). In the past ten years, notable advancements in the precision, safety, comfort, accessibility, and control of administration have been made to the established device-based neuromodulation techniques to improve their efficacy. In this chapter we discuss ten years of progress surrounding device-based neuromodulation techniques-Electroconvulsive Therapy (ECT), Transcranial Magnetic Stimulation (TMS), Magnetic Seizure Therapy (MST), Transcranial Focused Ultrasound (TUS), Deep Brain Stimulation (DBS), Vagus Nerve Stimulation (VNS), and Transcranial Electrical Stimulation (tES)-as research and clinical tools for enhancing fear extinction and treating PTSD symptoms. Additionally, we consider the emerging research, current limitations, and possible future directions for these techniques.

Recent advances in psychoradiology

Psychiatry, as a field, lacks objective markers for diagnosis, progression, treatment planning, and prognosis, in part due to difficulties studying the brain in vivo, and diagnoses are based on self-reported symptoms and observation of patient behavior and cognition. Rapid advances in brain imaging techniques allow clinical investigators to noninvasively quantify brain features at the structural, functional, and molecular levels. Psychoradiology is an emerging discipline at the intersection of psychiatry and radiology. Psychoradiology applies medical imaging technologies to psychiatry and promises not only to improve insight into structural and functional brain abnormalities in patients with psychiatric disorders but also to have potential clinical utility. We searched for representative studies related to recent advances in psychoradiology through May 1, 2022, and conducted a selective review of 165 references, including 75 research articles. We summarize the novel dynamic imaging processing methods to model brain networks and present imaging genetics studies that reveal the relationship between various neuroimaging endophenotypes and genetic markers in psychiatric disorders. Furthermore, we survey recent advances in psychoradiology, with a focus on future psychiatric diagnostic approaches with dimensional analysis and a shift from group-level to individualized analysis. Finally, we examine the application of machine learning in psychoradiology studies and the potential of a novel option for brain stimulation treatment based on psychoradiological findings in precision medicine. Here, we provide a summary of recent advances in psychoradiology research, and we hope this review will help guide the practice of psychoradiology in the scientific and clinical fields.

An evidence-based approach to psychopharmacology for posttraumatic stress disorder (PTSD) - 2022 update

Algorithms for posttraumatic stress disorder were published by this team in 1999 and 2011. Developments since then warrant revision. New studies and review articles from January 2011 to November 2021 were identified via PubMed and analyzed for evidence supporting changes. Following consideration of variations required by special patient populations, treatment of sleep impairments remains as the first recommended step. Nightmares and non-nightmare disturbed awakenings are best addressed with the anti-adrenergic agent prazosin, with doxazosin and clonidine as alternatives. First choices for difficulty initiating sleep include hydroxyzine and trazodone. If significant non-sleep PTSD symptoms remain, an SSRI should be tried, followed by a second SSRI or venlafaxine as a third step. Second generation antipsychotics can be considered, particularly for SSRI augmentation when PTSD-associated psychotic symptoms are present, with the caveat that positive evidence is limited and side effects are considerable. Anti-adrenergic agents can also be considered for general PTSD symptoms if not already tried, though evidence for daytime use lags that available for sleep. Regarding other pharmacological and procedural options, e.g., transcranial magnetic stimulation, cannabinoids, ketamine, psychedelics, and stellate ganglion block, evidence does not yet support firm inclusion in the algorithm. An interactive version of this work can be found at www.psychopharm.mobi.

Involvement of the brain-heart axis in the link between PTSD and cardiovascular disease

Posttraumatic stress disorder (PTSD) has long been associated with a heightened risk of cardiovascular disease (CVD). A number of mechanisms have been implicated to underlie this brain-heart axis relationship, such as altered functioning of the autonomic nervous system and increased systemic inflammation. While neural alterations have repeatedly been observed in PTSD, they are rarely considered in the PTSD-CVD link. The brain-heart axis is a pathway connecting frontal and limbic brain regions to the brainstem and periphery via the autonomic nervous system and it may be a promising model for understanding CVD risk in PTSD given its overlap with PTSD neural deficits. We first provide a summary of the primary mechanisms implicated in the association between PTSD and CVD. We then review the brain-heart axis and its relevance to PTSD, as well as findings from PTSD trials demonstrating that a number of PTSD treatments have effects on areas of the brain-heart axis. Finally, we discuss sex considerations in the PTSD-CVD link. A critical next step in this study is to determine if PTSD treatments that affect the brain-heart axis (e.g., brain stimulation that improves autonomic function) also reduce the risk of CVD.

Acute sleep interventions as an avenue for treatment of trauma-associated disorders

Scientific evidence that acute, posttrauma sleep disturbances (eg, nightmares and insomnia) can contribute significantly to the pathogenesis of trauma-induced disorders is compelling. Sleep disturbances precipitating from trauma are uniquely predictive of daytime posttrauma symptom occurrence and severity, as well as subsequent onset of mental health disorders, including post-traumatic stress disorder. Conversely, adequate sleep during the acute posttrauma period is associated with reduced likelihood of adverse mental health outcomes. These findings, which are broadly consistent with what is known about the role of sleep in the regulation of emotion, suggest that the acute posttrauma period constitutes a "window of opportunity" during which treatment of sleep disturbances may be especially effective for preventing or mitigating progression of aberrant psychophysiological processes. At this point, the weight of the scientific evidence supporting this possibility warrants initiation of clinical trials to confirm the benefits of targeted prophylactic sleep enhancement, and to establish treatment guidelines as appropriate.

CITATION

Swift KM, Thomas CL, Balkin TJ, Lowery-Gionta EG, Matson LM. Acute sleep interventions as an avenue for treatment of trauma-associated disorders. J Clin Sleep Med. 2022;18(9):2291-2312.

Invisible wounds: Suturing the gap between the neurobiology, conventional and emerging therapies for posttraumatic stress disorder

A sharp increase in the prevalence of neuropsychiatric disorders, including major depression, anxiety, substance use disorders and posttraumatic stress disorder (PTSD) has occurred due to the traumatic nature of the persisting COVID-19 global pandemic. PTSD is estimated to occur in up to 25% of individuals following exposure to acute or chronic trauma, and the pandemic has inflicted both forms of trauma on much of the population through both direct physiological attack as well as an inherent upheaval to our sense of safety. However, despite significant advances in our ability to define and apprehend the effects of traumatic events, the neurobiology and neuroanatomical circuitry of PTSD, one of the most severe consequences of traumatic exposure, remains poorly understood. Furthermore, the current psychotherapies or pharmacological options for treatment have limited efficacy, durability, and low adherence rates. Consequently, there is a great need to better understand the neurobiology and neuroanatomy of PTSD and develop novel therapies that extend beyond the current limited treatments. This review summarizes the neurobiological and neuroanatomical underpinnings of PTSD and discusses the conventional and emerging psychotherapies, pharmacological and combined psychopharmacological therapies, including the use of psychedelic-assisted psychotherapies and neuromodulatory interventions, for the improved treatment of PTSD and the potential for their wider applications in other neuropsychiatric disorders resulting from traumatic exposure.

Repetitive transcranial magnetic stimulation for post-traumatic stress disorder: Lights and shadows

We have read with interest the publication that describes the available data related to the use of neuromodulation strategies for the treatment of post-traumatic stress disorder (PTSD). Despite treatment advances, however, a substantial proportion of PTSD patients receiving psychological and/or pharmacological treatment do not reach an adequate clinical response. In their paper, the authors draw attention to the current understanding of the use of repetitive transcranial magnetic stimulation (rTMS) as a potential treatment for PTSD. Most of the previous studies indeed applied both inhibitory (1 Hz) and excitatory (> 1 Hz, up to 20 Hz) rTMS to the right and/or left dorsolateral prefrontal cortex. Despite larger therapeutic effects observed when high-frequency stimulation was applied, the question of which side and frequency of stimulation is the most successful is still debated. The authors also reported on the after-effect of rTMS related to neuroplasticity and identified the intermittent theta burst stimulation as a technique of particular interest because of it showed the most effective improvement on PTSD symptoms. However, although numerous studies have highlighted the possible beneficial use of rTMS protocols for PTSD, the exact mechanism of action remains unclear. In their conclusions, the authors stated that rTMS has been demonstrated to be effective for the treatment of PTSD symptoms. Nevertheless, we believe that further research with homogeneous samples, standardized protocols, and objective outcome measures is needed to identify specific therapeutic targets and to better define significant changes when active and sham stimulation procedures are compared.

The Use of Repetitive Transcranial Magnetic Stimulations for the Treatment of Post-Traumatic Stress Disorder: A Scoping Review

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive procedure in which brain neural activity is stimulated by the direct application of a magnetic field to the scalp. Despite its wide and continuous usage for the management of psychiatric disorders, the use of rTMS for post-traumatic stress disorder (PTSD) is not well established and evaluated by researchers. This scoping review seeks to explore the relevant literature available regarding the use of rTMS as a mode of treatment for PTSD, to map evidence in support of the use of rTMS for PTSD, and recommendations on future clinical and research work. Five databases were searched (MEDLINE, CINAHL, Psych INFO, SCOPUS, and EMBASE) to identify empirical studies and randomized controlled trials aimed at the treatment of PTSD with rTMS. A total of 10 studies were eligible for this review. The search results are up to date as of the date of the electronic data search of 20 December 2020. The frequencies applied in the studies ranged from low (1 Hz) to high (10 Hz) at different thresholds. Nine reported significant positive outcomes and PTSD symptoms improvement. rTMS was reported as well tolerated with no significant side effects. The application of rTMS for PTSD looks promising despite the diversity in terms of its outcomes and its clinical significance. Studies with well-defined stimulation parameters need to be conducted in the future.

Prefrontal transcranial magnetic stimulation for depression in US military veterans - A naturalistic cohort study in the veterans health administration

BACKGROUND

Repetitive transcranial magnetic stimulation (TMS) is an evidence-based treatment for pharmacoresistant major depressive disorder (MDD), however, the evidence in veterans has been mixed. To this end, VA implemented a nationwide TMS program that included evaluating clinical outcomes within a naturalistic design. TMS was hypothesized to be safe and provide clinically meaningful reductions in MDD and posttraumatic stress disorder (PTSD) symptoms.

METHODS

Inclusion criteria were MDD diagnosis and standard clinical TMS eligibility. Of the 770 patients enrolled between October 2017 and March 2020, 68.4% (n = 521) met threshold-level PTSD symptom criteria. Treatments generally used standard parameters (e.g., left dorsolateral prefrontal cortex, 120% motor threshold, 10 Hz, 3000 pulses/treatment). Adequate dose was operationally defined as 30 sessions. MDD and PTSD symptoms were measured using the 9-item patient health questionnaire (PHQ-9) and PTSD checklist for DSM-5 (PCL-5), respectively.

RESULTS

Of the 770 who received at least one session, TMS was associated with clinically meaningful (Cohen's d>1.0) and statistically significant (all p<.001) reductions in MDD and PTSD. Of the 340 veterans who received an adequate dose, MDD response and remission rates were 41.4% and 20%, respectively. In veterans with comorbid PTSD, 65.3% demonstrated clinically meaningful reduction and 46.1% no longer met PTSD threshold criteria after TMS. Side effects were consistent with the known safety profile of TMS.

LIMITATIONS

Include those inherent to retrospective observational cohort study in Veterans.

CONCLUSIONS

These multisite, large-scale data supports the effectiveness and safety of TMS for veterans with MDD and PTSD using standard clinical approaches.

Neuromodulation Treatments of Pathological Anxiety in Anxiety Disorders, Stressor-Related Disorders, and Major Depressive Disorder: A Dimensional Systematic Review and Meta-Analysis

BACKGROUND

Pathological anxiety is responsible for major functional impairments and resistance to conventional treatments in anxiety disorders (ADs), posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). Focal neuromodulation therapies such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS) are being developed to treat those disorders.

METHODS

We performed a dimensional systematic review and meta-analysis to assess the evidence of the efficacy of TMS, tDCS and DBS in reducing anxiety symptoms across ADs, PTSD and MDD. Reports were identified through systematic searches in PubMed/Medline, Scopus and Cochrane library (inception to November 2020), followed by review according to the PRISMA guidelines. Controlled clinical trials examining the effectiveness of brain stimulation techniques on generic anxiety symptoms in patients with ADs, PTSD or MDD were selected.

RESULTS

Nineteen studies (RCTs) met inclusion criteria, which included 589 participants. Overall, focal brain activity modulation interventions were associated with greater reduction of anxiety levels than controls [SMD: -0.56 (95% CI, -0.93 to-0.20, I ² = 77%]. Subgroup analyses revealed positive effects for TMS across disorders, and of focal neuromodulation in generalized anxiety disorder and PTSD. Rates of clinical responses and remission were higher in the active conditions. However, the risk of bias was high in most studies.

CONCLUSIONS

There is moderate quality evidence for the efficacy of neuromodulation in treating pathological anxiety.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=233084, identifier: PROSPERO CRD42021233084. It was submitted on January 29th, 2021, and registered on March 1st, 2021. No amendment was made to the recorded protocol. A change was applied for the subgroup analyses based on target brain regions, we added the putative nature (excitatory/inhibitory) of brain activity modulation.

Transcranial Magnetic Stimulation for Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a psychiatric disorder that causes significant functional impairment and is related to altered stress response and reinforced learned fear behavior. PTSD has been found to impact three functional networks in the brain: default mode, executive control, and salience. The executive control network includes the dorsolateral prefrontal cortex (DLPFC) and lateral PPC. The salience network involves the anterior cingulate cortex, anterior insula, and amygdala. This latter network has been found to have increased functional connectivity in PTSD. Transcranial Magnetic Stimulation (TMS) is a technique used in treating PTSD and involves stimulating specific portions of the brain through electromagnetic induction. Currently, high-frequency TMS applied to the left dorsolateral prefrontal cortex (DLPFC) is approved for use in treating major depressive disorder (MDD) in patients who have failed at least one medication trial. In current studies, high-frequency stimulation has been shown to be more effective in PTSD rating scales posttreatment than low-frequency stimulation. The most common side effect is headache and scalp pain treated by mild analgesics. Seizures are a rare side effect and are usually due to predisposing factors. Studies have been done to assess the overall efficacy of TMS. However, results have been conflicting, and sample sizes were small. More research should be done with larger sample sizes to test the efficacy of TMS in the treatment of PTSD. Overall, TMS is a relatively safe treatment. Currently, the only FDA- approved to treat refractory depression, but with the potential to treat many other conditions.

Transcranial magnetic stimulation for post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric disorder. While current treatment options are effective for some, many individuals fail to respond to first-line psychotherapies and pharmacotherapy. Transcranial magnetic stimulation (TMS) has emerged over the past several decades as a noninvasive neuromodulatory intervention for psychiatric disorders including depression, with mounting evidence for its safety, tolerability, and efficacy in treating PTSD. While several meta-analyses of TMS for PTSD have been published to date showing large effect sizes on PTSD overall, there is marked variability between studies, making it difficult to draw simple conclusions about how best to treat patients. The following review summarizes over 20 years of the existing literature on TMS as a PTSD treatment, and includes nine randomized controlled trials and many other prospective studies of TMS monotherapy, as well as five randomized controlled trials investigating TMS combined with psychotherapy. While the majority of studies utilize repetitive TMS targeted to the right dorsolateral prefrontal cortex (DLPFC) at low frequency (1 Hz) or high frequency (10 or 20 Hz), others have used alternative frequencies, targeted other regions (most commonly the left DLPFC), or trialed different stimulation protocols utilizing newer TMS modalities such as synchronized TMS and theta-burst TMS (TBS). Although it is encouraging that positive outcomes have been shown, there is a paucity of studies directly comparing available approaches. Biomarkers, such as functional imaging and electroencephalography, were seldomly incorporated yet remain crucial for advancing our knowledge of how to predict and monitor treatment response and for understanding mechanism of action of TMS in this population. Effects on PTSD are often sustained for up to 2-3 months, but more long-term studies are needed in order to understand and predict duration of response. In short, while TMS appears safe and effective for PTSD, important steps are needed to operationalize optimal approaches for patients suffering from this disorder.

Clinical application of repetitive transcranial magnetic stimulation for post-traumatic stress disorder: A literature review

The efficacy of traditional treatment for post-traumatic stress disorder (PTSD) is still unsatisfactory. Repetitive transcranial magnetic stimulation (rTMS) has been widely used in the treatment of various types of mental disorders, including PTSD. Although rTMS has been demonstrated to be effective in many cases, there are still arguments regarding its mechanism and protocol. This review aims to summarize the origin, development, principle, and future direction of rTMS and introduce this neuro-stimulation therapy to relevant clinicians.

Repetitive Transcranial Magnetic Stimulation for the Treatment of Post-traumatic Stress Disorder: A Systematic Review and Network Meta-analysis: La Stimulation Magnétique Transcrânienne Répétitive Pour le Traitement du Trouble de Stress Post-Traumatique : Une Revue Systématique et une Méta-Analyse en Réseau

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a promising treatment modality for Post-traumatic stress disorder (PTSD). Several targets and stimulation parameters have been investigated, and while previous meta-analyses have suggested that rTMS is efficacious, these have pooled different stimulation parameters and targets, and the relative efficacy of each is unknown.

METHODS

We therefore performed a systematic review and network meta-analysis of randomized controlled trials (RCTs) by searching MEDLINE, EMBASE, CENTRAL, and PsycINFO and retaining RCTs with at least 5 individuals per arm and clinician-rated PTSD symptoms (PROSPERO CRD42019134984). We adhered to PRISMA guidelines, and 2 independent reviewers screened studies for eligibility and extracted the primary outcome of clinician-rated PTSD symptoms. Dropouts were extracted as a proxy for acceptability. Random effects pairwise meta-analyses and a network meta-analysis were performed.

RESULTS

We synthesize data from 10 RCTs with a total of 421 participants. Two rTMS interventions targeting the right dorsolateral prefrontal cortex (DLPFC) improved PTSD symptoms relative to sham: low-frequency stimulation (SMD = 0.70; 95% CI, 0.22 to 1.18) and high-frequency stimulation (SMD = 0.71; 95% CI, 0.11 to 1.31). Medial PFC dTMS, right DLPFC intermittent theta-burst stimulation, and left DLPFC high-frequency stimulation did not separate from sham. Dropouts as a proxy for acceptability revealed no differences between any of the active conditions or sham nor did any of the active conditions differ from each other.

CONCLUSION

The current literature does not support efficacy differences between interventions; however, protocols stimulating the right DLPFC appear superior to sham. It is unclear whether this reflects heterogeneity in pathology requiring a personalized medicine approach or nonspecific mechanisms of rTMS.

Safety learning during development: Implications for development of psychopathology

Fear and safety learning are necessary adaptive behaviors that develop over the course of maturation. While there is a large body of literature regarding the neurobiology of fear and safety learning in adults, less is known regarding safety learning during development. Given developmental changes in the brain, there are corresponding changes in safety learning that are quantifiable; these may serve to predict risk and point to treatment targets for fear and anxiety-related disorders in children and adolescents. For healthy, typically developing youth, the main developmental variation observed is reduced discrimination between threat and safety cues in children compared to adolescents and adults, while lower expression of extinction learning is exhibited in adolescents compared to adults. Such distinctions may be related to faster maturation of the amygdala relative to the prefrontal cortex, as well as incompletely developed functional circuits between the two. Fear and anxiety-related disorders, childhood maltreatment, and behavioral problems are all associated with alterations in safety learning for youth, and this dysfunction may proceed into adulthood with corresponding abnormalities in brain structure and function-including amygdala hypertrophy and hyperreactivity. As impaired inhibition of fear to safety may reflect abnormalities in the developing brain and subsequent psychopathology, impaired safety learning may be considered as both a predictor of risk and a treatment target. Longitudinal neuroimaging studies over the course of development, and studies that query change with interventions are needed in order to improve outcomes for individuals and reduce long-term impact of developmental psychopathology.

Transcranial magnetic stimulation as a treatment for posttraumatic stress disorder: A meta-analysis

BACKGROUND

Posttraumatic stress disorder (PTSD) is a pervasive mental health condition with limited treatment success. Transcranial magnetic stimulation (TMS) has shown positive outcomes for people with PTSD, using different treatment protocols. This meta-analysis sought to examine which variables in TMS treatment are associated with treatment benefits.

METHODS

A literature search of major online research databases from inception to September 15, 2020 was conducted to identify primary research studies using TMS to treat PTSD. Treatment effect data and TMS treatment variables were coded and analysed using a random effects model. Meta-regression and analyses of moderating variables were conducted to ascertain which variables were associated with significant treatment effects.

RESULTS

An overall effect size of d = 1.17, 95% CI [0.89 - 1.45] for TMS as a treatment for PTSD was found. Analysis of moderators showed that there was a significantly larger treatment effect for high frequency TMS (d = 1.44) compared with low frequency (d = 0.72), p = .006; there was no significant difference between TMS targeting the left dorsolateral prefrontal cortex (DLPFC) and the right DLPFC; and larger treatment doses were not associated with stronger treatment effects.

LIMITATIONS

Not all published studies were available in English or reported the necessary data to be included in this meta-analysis.

CONCLUSIONS

TMS shows potential as a treatment for PTSD, although further research is required to understand the neurological mechanisms of TMS on specific PTSD symptoms so that more effective treatment can be designed for individuals.

Advances in repetitive transcranial magnetic stimulation for posttraumatic stress disorder: A systematic review

Repetitive transcranial magnetic stimulation (rTMS) as a treatment for posttraumatic stress disorder (PTSD) has gained interest over the past two decades. However, it has yet to be recommended in major treatment guidelines. We conducted a systematic review of randomized controlled trials to examine the efficacy of rTMS for PTSD. Thirteen studies with 549 participants were included in this review. We compared the effects of (1) rTMS versus sham, and (2) high-frequency (HF) versus low-frequency (LF) rTMS, on posttreatment PTSD scores and other secondary outcomes. We calculated the standardized mean differences (SMD) to determine the direction of effects, and unstandardized mean differences to estimate the magnitude of efficacy. At post-treatment, rTMS was superior to sham comparison in reducing PTSD (SMD = -1.13, 95% CI: -2.10 to -0.15) and depression severity (SMD = -0.83, 95% CI: -1.30 to -0.36). The quality of evidence, however, was rated very low due to small samples sizes, treatment heterogeneity, inconsistent results, and an imprecise pooled effect. HF rTMS was associated with slightly improved, albeit imprecise, outcomes compared to LF rTMS on PTSD (SMD = -0.19, 95% CI: -1.39 to 1.00) and depression (SMD = -1.09, 95% CI: -1.65 to -0.52) severity. Further research is required to advance the evidence on this treatment.

Neurostimulation for treatment-resistant posttraumatic stress disorder: an update on neurocircuitry and therapeutic targets

Posttraumatic stress disorder (PTSD) is a widespread and often devastating psychiatric condition. Core symptoms include intrusive and distressing thoughts, heightened reactivity, mood changes, cognitive impairments, and consequent avoidance of trauma-related stimuli. Symptoms of PTSD are often refractory to standard treatments, and neuromodulatory techniques have therefore drawn significant interest among the most treatment-resistant patients. Transcranial magnetic stimulation has demonstrated minimal efficacy, and deep brain stimulation trials are currently ongoing. PTSD is a disorder of neural circuitry; the current understanding includes involvement of the amygdala (basolateral and central nuclei), the prefrontal cortex (ventral medial and dorsolateral regions), and the hippocampus. Neuroimaging and optogenetic studies have improved the understanding of large-scale neural networks and the effects of microcircuitry manipulation, respectively. This review discusses the current PTSD literature and ongoing neurostimulation trials, and it highlights the current understanding of neuronal circuit dysfunction in PTSD. The authors emphasize the anatomical correlations of PTSD's hallmark symptoms, offer another potential deep brain stimulation target for PTSD, and note the need for continued research to identify useful biomarkers for the development of closed-loop therapies. Although there is hope that neuromodulation will become a viable treatment modality for PTSD, this concept remains theoretical, and further research should involve institutional review board-approved controlled prospective clinical studies.

Repetitive Transcranial Magnetic Stimulation for the Treatment of Depression, Post-Traumatic Stress Disorder, and Suicidal Ideation in Military Populations: A Scholarly Review

INTRODUCTION

Military mental health conditions, such as depression, PTSD, and suicidal ideation, are currently understudied and undertreated. Repetitive transcranial magnetic stimulation (rTMS) is currently being considered as a treatment for these conditions; however, there exists a paucity of research in this area. This scholarly review will examine the limitations of the existing literature on the use of rTMS to treat depression, PTSD, and suicidal ideation in service members (SMs) and veterans.

MATERIALS AND METHODS

Publications that evaluated rTMS for the treatment of depression, PTSD, or suicidal ideation in military samples were identified via a PubMed search. Non-interventional rTMS studies, studies where the sample could not be confirmed to be primarily composed of SMs or veteran participants, studies without psychiatric outcome measures, and studies not published in a peer-reviewed journal were excluded from this review.

RESULTS

This literature search identified 20 total publications (eight primary analyses of randomized controlled trials (RCTs), one longitudinal analysis of an RCT, five open label trials, and six retrospective analyses of clinical data), inclusive of 879 participants. Eighteen studies utilized a protocol targeting the prefrontal cortex (PFC), and one of these also targeted the supplementary motor area (SMA) with the PFC (one study did not specify the stimulation site). Eight studies applied standard 10 Hz frequency stimulation, and four applied standard 1 Hz frequency stimulation. The remainder of studies applied alternative stimulation protocols including 5 Hz (two studies), 20 Hz (one study), a combination of 1 and 10 Hz (two studies), and theta burst stimulation (TBS) (two studies). Twelve studies reported significant results, including four RCTs, three open label studies, and five retrospective analyses.

CONCLUSIONS

rTMS offers a promising area of research for mental health conditions in military populations. However, the number of studies that focus specifically on this population are few in number and have many notable limitations. Further research is needed to validate the effectiveness of this tool for SMs and veterans.

The Effects of Functionally Guided, Connectivity-Based rTMS on Amygdala Activation

While repetitive transcranial magnetic stimulation (rTMS) is widely used to treat psychiatric disorders, innovations are needed to improve its efficacy. An important limitation is that while psychiatric disorders are associated with fronto-limbic dysregulation, rTMS does not have sufficient depth penetration to modulate affected subcortical structures. Recent advances in task-related functional connectivity provide a means to better link superficial and deeper cortical sources with the possibility of increasing fronto-limbic modulation to induce stronger therapeutic effects. The objective of this pilot study was to test whether task-related, connectivity-based rTMS could modulate amygdala activation through its connectivity with the medial prefrontal cortex (mPFC). fMRI was collected to identify a node in the mPFC showing the strongest connectivity with the amygdala, as defined by psychophysiological interaction analysis. To promote Hebbian-like plasticity, and potentially stronger modulation, 5 Hz rTMS was applied while participants viewed frightening video-clips that engaged the fronto-limbic network. Significant increases in both the mPFC and amygdala were found for active rTMS compared to sham, offering promising preliminary evidence that functional connectivity-based targeting may provide a useful approach to treat network dysregulation. Further research is needed to better understand connectivity influences on rTMS effects to leverage this information to improve therapeutic applications.

Closed-loop neurostimulation for affective symptoms and disorders: An overview

Affective and anxiety disorders are the most prevalent and incident psychiatric disorders worldwide. Therapeutic approaches to these disorders using non-invasive brain stimulation (NIBS) and analogous techniques have been extensively investigated. In this paper, we discuss the combination of NIBS and neurofeedback in closed-loop setups and its application for affective symptoms and disorders. For this, we first provide a rationale for this combination by presenting some of the main original findings of NIBS, with a primary focus on transcranial magnetic stimulation (TMS), and neurofeedback, including protocols based on electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Then, we provide a scope review of studies combining real-time neurofeedback with NIBS protocols in the so-called closed-loop brain state-dependent neuromodulation (BSDS). Finally, we discuss the concomitant use of TMS and real-time functional near-infrared spectroscopy (fNIRS) as a possible solution to the current limitations of BSDS-based protocols for affective and anxiety disorders.

Augmentation of fear extinction by theta-burst transcranial magnetic stimulation of the prefrontal cortex in humans

BACKGROUND

Fear extinction alone does not erase the original fear memory. Interventions that enhance extinction can be beneficial for the treatment of fear-related disorders. Repetitive transcranial magnetic stimulation has been shown to improve memory performance. The present study examined the effects of intermittent theta-burst stimulation (iTBS) on fear extinction and the return of fear memory in humans.

METHODS

Ninety-one young healthy volunteers underwent 3 experiments using a randomized controlled experimental design. Participants first acquired fear conditioning, after which they received 30 Hz iTBS before and after extinction training. The iTBS was applied to 1 of 2 targets: the left dorsolateral prefrontal cortex (dlPFC) and the vertex (control). Fear responses were measured 24 hours later and 1 month later.

RESULTS

During the spontaneous recovery and reinstatement tests, iTBS of the left dlPFC before and after extinction significantly reduced fear response, whereas iTBS of the vertex had no effect on fear memory performance. This combined approach had a relatively long-lasting effect (i.e., at least 1 month).

LIMITATIONS

We did not explore the effect of iTBS of the dlPFC on the expression of fear without extinction training. The neural mechanisms of iTBS with fear extinction to inhibit the fear response are unclear. Our results are preliminary and should be interpreted with caution.

CONCLUSION

`The present results showed that 30 Hz iTBS of the left dlPFC enhanced retention of fear extinction. Our study introduces a new intervention for fear memory and suggests that the left dlPFC may be a treatment target for fear-related disorders.

Transcranial magnetic stimulation therapeutic applications on sleep and insomnia: a review

Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulatory technique approved by the US Food and Drug Administration for use in treatment-resistant major depressive disorder. It works by generating localized magnetic fields that create depolarizing electrical currents in neurons a few centimeters below the scalp. This localized effect is believed to stimulate neural plasticity, activate compensatory processes, and influence cortical excitability. Additionally, rTMS has been used in a variety of clinical trials for neurological and psychiatric conditions such as anxiety, post-traumatic stress disorder and epilepsy. Beneficial effects in sleep parameters have been documented in these trials, as well as in major depressive disorder, and have led to an interest in using rTMS in the field of sleep medicine for specific disorders such as insomnia, hypersomnia, and restless legs syndrome. It is unknown whether rTMS has intrinsically beneficial properties when applied to primary sleep disorders, or if it only acts on sleep through mood disorders. This narrative review sought to examine available literature regarding the application of rTMS for sleep disorder to identify knowledge gaps and inform future study design. The literature in this area remains scarce, with few randomized clinical trials on rTMS and insomnia. Available studies have found mixed results, with some studies reporting subjective sleep improvement while objective improvement is less consistent. Due to the heterogeneity of results and the variations in rTMS protocols, no definitive conclusions have been reached, signaling the need for further research.

The Effects of Repetitive Transcranial Magnetic Stimulation on Anxiety in Patients With Moderate to Severe Traumatic Brain Injury: A Post-hoc Analysis of a Randomized Clinical Trial

Background: Traumatic brain injury (TBI) is one of the leading causes of neuropsychiatric disorders in young adults. Repetitive Transcranial Magnetic Stimulation (rTMS) has been shown to improve psychiatric symptoms in other neurologic disorders, such as focal epilepsy, Parkinson's disease, and fibromyalgia. However, the efficacy of rTMS as a treatment for anxiety in persons with TBI has never been investigated. This exploratory post-hoc analyzes the effects of rTMS on anxiety, depression and executive function in participants with moderate to severe chronic TBI. Methods: Thirty-six participants with moderate to severe TBI and anxiety symptoms were randomly assigned to an active or sham rTMS condition in a 1:1 ratio. A 10-session protocol was used with 10-Hz rTMS stimulation over the left dorsolateral prefrontal cortex (DLPFC) for 20 min each session, a total of 2,000 pulses were applied at each daily session (40 stimuli/train, 50 trains). Anxiety symptoms; depression and executive function were analyzed at baseline, after the last rTMS session, and 90 days post intervention. Results: Twenty-seven participants completed the entire protocol and were included in the post-hoc analysis. Statistical analysis showed no interaction of group and time (p > 0.05) on anxiety scores. Both groups improved depressive and executive functions over time, without time and group interaction (p _s < 0.05). No adverse effects were reported in either intervention group. Conclusion: rTMS did not improve anxiety symptoms following high frequency rTMS in persons with moderate to severe TBI. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02167971.

A Randomized Sham-controlled Trial of 1-Hz and 10-Hz Repetitive Transcranial Magnetic Stimulation (rTMS) of the Right Dorsolateral Prefrontal Cortex in Civilian Post-traumatic Stress Disorder: Un essai randomisé contrôlé simulé de stimulation magnétique transcrânienne repetitive (SMTr) de 1 Hz et 10 Hz du cortex préfrontal dorsolatéral droit dans le trouble de stress post-traumatique chez des civils

OBJECTIVE

Despite effective psychological and pharmacological treatments, there is a large unmet burden of illness in post-traumatic stress disorder (PTSD). Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive intervention and a putative treatment strategy for PTSD. The evidence base to date suggests that rTMS targeting the dorsolateral prefrontal cortex (DLPFC), in particular the right DLPFC, leads to improvements in PTSD symptoms. However, optimal stimulation parameters have yet to be determined. In this study, we examine the efficacy of high- and low-frequency rTMS of the right DLPFC using a randomized, double-blind, sham-controlled design in civilian PTSD.

METHODS

We conducted a 2-week single-site randomized sham-controlled trial of rTMS targeting the right DLPFC. We recruited civilians aged 19 to 70 with PTSD and randomized subjects with allocation concealment to daily 1-Hz rTMS, 10-Hz rTMS, or sham rTMS. The primary outcome was improvement in Clinician Administered PTSD Scale-IV (CAPS-IV). Secondary outcomes included change in depressive and anxiety symptoms.

RESULTS

We recruited 31 civilians with PTSD. One 1-Hz-treated patient developed transient suicidal ideation. Analyses revealed significant improvement in CAPS-IV symptoms in the 1-Hz group relative to sham (Hedges' g = -1.07) but not in the 10-Hz group. This was not attributable to changes in anxious or depressive symptomatology. Ten-Hz stimulation appeared to improve depressive symptoms compared to sham.

CONCLUSION

Low-frequency rTMS is efficacious in the treatment of civilian PTSD. Our data suggest that high-frequency rTMS of the right DLPFC is worthy of additional investigation for the treatment of depressive symptoms comorbid with PTSD.

Treating Post-traumatic Stress Disorder with Neuromodulation Therapies: Transcranial Magnetic Stimulation, Transcranial Direct Current Stimulation, and Deep Brain Stimulation

Post-traumatic stress disorder (PTSD) is a prevalent and debilitating illness. While standard treatment with pharmacotherapy and psychotherapy may be effective, approximately 20 to 30% of patients remain symptomatic. These individuals experience depression, anxiety, and elevated rates of suicide. For treatment-resistant patients, there is a growing interest in the use of neuromodulation therapies, including transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS). We conducted a systematic review on the use of neuromodulation strategies for PTSD and pooled 13 randomized clinical trials (RCTs), 11 case series, and 6 case reports for analysis. Overall, most studies reported favorable outcomes in alleviating both PTSD and depressive symptoms. Although several RCTs described significant differences when active and sham stimulations were compared, others found marginal or nonsignificant differences between groups. Also positive were studies comparing PTSD symptoms before and after treatment. The side effect profile with all 3 modalities was found to be low, with mostly mild adverse events being reported. Despite these encouraging data, several aspects remain unknown. Given that PTSD is a highly heterogeneous condition that can be accompanied by distinct psychiatric diagnoses, defining a unique treatment for this patient population can be quite challenging. There has also been considerable variation across trials regarding stimulation parameters, symptomatic response, and the role of adjunctive psychotherapy. Future studies are needed to address these issues.

A Secondary Analysis on Effects of Theta Burst Transcranial Magnetic Stimulation to Reduce Anger in Veterans With Posttraumatic Stress Disorder

INTRODUCTION

Anger is an important clinical feature of posttraumatic stress disorder (PTSD) that can hamper recovery. We recently reported that intermittent theta burst stimulation (iTBS) demonstrated preliminary efficacy to reduce symptoms of posttraumatic stress disorder and major depression; here, we performed a secondary analysis testing whether iTBS reduced symptoms of anger over the course of iTBS treatment and compared to sham stimulation.

MATERIALS AND METHODS

Fifty veterans with chronic PTSD received ten daily sessions of sham-controlled, double-blind iTBS (1800 pulses/session, once per weekday) targeting the right dorsolateral prefrontal cortex (intent-to-treat = 25 per group). Participants who completed the double-blind phase were offered another ten sessions of unblinded iTBS. Participants completed the Dimensions of Anger Reactions scale at pre-iTBS baseline, treatment midpoints, and endpoints of the blinded and unblinded phases, and at one-month after the last stimulation session. Correlations between anger, PTSD, depression, and sleep were also explored.

RESULTS

After the first week, during the double-blind phase, participants randomized to active stimulation reported significantly reduced anger compared to sham stimulation (p = 0.04). Participants initially randomized to sham appeared to catch-up to the point they no longer differed from those initially randomized to active iTBS when they received iTBS during the unblinded phase (p = 0.14). Anger reduction was maintained at one-month after iTBS in participants initially randomized to active stimulation (i.e., total of four weeks of iTBS).

CONCLUSIONS

This secondary analysis suggests that iTBS might reduce anger in veterans with PTSD. Future studies focused on more granular level anger outcomes and effects of number of stimulation sessions are needed.

Non-pharmacological and non-psychological approaches to the treatment of PTSD: results of a systematic review and meta-analyses

BACKGROUND

Non-pharmacological and non-psychological approaches to the treatment of post-traumatic stress disorder (PTSD) have often been excluded from systematic reviews and meta-analyses. Consequently, we know little regarding their efficacy.

OBJECTIVE

To determine the effect sizes of non-pharmacological and non-psychological treatment approaches for PTSD.

METHOD

We undertook a systematic review and meta-analyses following Cochrane Collaboration guidelines. A pre-determined definition of clinical importance was applied to the results and the quality of evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

RESULTS

30 randomised controlled trials (RCTs) of a range of heterogeneous non-psychological and non-pharmacological interventions (28 in adults, two in children and adolescents) were included. There was emerging evidence for six different approaches (acupuncture, neurofeedback, saikokeishikankyoto (a herbal preparation), somatic experiencing, transcranial magnetic stimulation, and yoga).

CONCLUSIONS

Given the level of evidence available, it would be premature to offer non-pharmacological and non-psychological interventions routinely, but those with evidence of efficacy provide alternatives for people who do not respond to, do not tolerate or do not want more conventional evidence-based interventions. This review should stimulate further research in this area.

Transcranial Magnetic Stimulation Meets Virtual Reality: The Potential of Integrating Brain Stimulation With a Simulative Technology for Food Addiction

The aim of this perspective is to propose and discuss the integration of transcranial magnetic stimulation (TMS) over the dorsolateral prefrontal cortex with virtual reality (VR) food exposure for therapeutic interventions for food addiction. "Food addiction" is a dysfunctional eating pattern which is typically observed in eating disorders (ED) such as bulimia nervosa and binge eating disorder. Food addiction has been compared to substance use disorder due to the necessity of consuming a substance (food) and the presence of a dependence behavior. In recent years, VR has been applied in the treatment of ED because it triggers psychological and physiological responses through food exposure in place of real stimuli. Virtual reality-Cue exposure therapy has been proven as a valid technique for regulating anxiety and food craving in ED. More, TMS has been proven to modulate circuits and networks implicated in neuropsychiatric disorders and is effective in treating addiction such as nicotine craving and consumption and cocaine use disorder. The combination of a simulative technology and a neurostimulation would presumably provide better improvement compared to a single intervention because it implies the presence of both cognitive and neuropsychological techniques. The possible advantage of this approach will be discussed in the perspective.

Exploring Theta Burst Stimulation for Post-traumatic Stress Disorder in Australian Veterans—A Pilot Study

Introduction

Post-traumatic stress disorder (PTSD) is a severe and debilitating condition affecting a significant proportion of the veteran community. A substantial number of veterans with PTSD fail to benefit from trauma-focused psychological therapies or pharmacotherapy or are left with residual symptoms, and therefore, investigation of new and innovative treatment is required. Theta Burst Stimulation (TBS) is a novel form of Repetitive Transcranial Magnetic Stimulation, which has been shown to improve depression symptoms and associated cognitive deficits. The current pilot study aimed to explore the acceptability, safety, and tolerability of intermittent TBS (iTBS) as a treatment for PTSD in Australian veterans.

Materials and Methods

This study employed a case series, repeated-measures design. Eight Australian Defence Force veterans with PTSD received 20 bilateral iTBS treatments (1 session per day, 5 days per week over a 4-week period) and were assessed on a range of mental health and neuropsychological measures, including the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and Hamilton Depression Rating Scale (HAM-D), at pretreatment, post-treatment, and a 3-month follow-up.

Results

Treatment was generally welltolerated, with reported side-effects including mild to moderate site-specific cranial pain and headaches during stimulation, which were relieved with the use of low dose analgesics. No serious side effects or adverse events were reported. Participants exhibited reductions in both PTSD and depression symptom severity (the repeated-measures effect size [dRM] for the CAPS-5 was −1.78, and the HAM-D was −1.16 post-treatment), as well as improvements in working memory and processing speed. Although significance cannot be inferred, these preliminary estimates of effect size indicate change over time.

Conclusions

Bilateral iTBS appears to be welltolerated by Australian veterans. Within this repeated-measures case series, iTBS treatment shows promise in reducing both PTSD and mood symptoms, as well as improving cognitive difficulties associated with these disorders. Large-scale randomized controlled trials of this promising treatment are warranted.

Predicting and Managing Treatment Non-Response in Posttraumatic Stress Disorder

PURPOSE OF REVIEW

This review aims to synthesize existing research regarding the definition of treatment resistance in posttraumatic stress disorder (PTSD), predictors of treatment non-response to first-line interventions, and emerging second-line PTSD treatment options into an accessible resource for the practicing clinician.

RECENT FINDINGS

The concept of treatment resistance in PTSD is currently poorly defined and operationalized. There are no well-established predictors of treatment non-response utilized in routine clinical care, but existing research identifies several potential candidate markers, including male gender, low social support, chronic and early life trauma exposure, comorbid psychiatric disorders, severe PTSD symptoms, and poor physical health. The most promising available treatment options for PTSD patients non-responsive to first-line psychotherapies and antidepressants include transcranial magnetic stimulation and ketamine infusion. Methylenedioxymethamphetamine-assisted psychotherapy also appears promising but is only available in a research context. These options require careful consideration of risks and benefits for a particular patient.

SUMMARY

More research is required to develop a robust, clinically-useful definition of treatment resistance in PTSD; identify reliable, readily assessable, and generalizable predictors of PTSD treatment non-response; and implement measurement and prediction in clinical settings to identify individuals unlikely to respond to first-line treatments and direct them to appropriate second-line treatments.

Non-invasive brain stimulation for posttraumatic stress disorder: a systematic review and meta-analysis

Approximately 7-9% of people develop posttraumatic stress disorder in their lifetime, but standard pharmacological treatment or psychotherapy shows a considerable individual variation in their effectiveness. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) hold promise for the treatment of posttraumatic stress disorder. The objective of this meta-analysis was to summarize the existing evidence on the therapeutic effects of these brain stimulation treatments on posttraumatic core symptoms. We systematically retrieved articles published between 1st January 2000 and 1st January 2020 comparing the effects of active with sham stimulation or no intervention in posttraumatic patients from eight databases. Random-effects model was used for meta-analysis. Meta-regression and subgroup meta-analysis was performed to investigate the influence of stimulation dose and different stimulation protocols, respectively. 20 studies were included in this review, where of 11 randomized controlled trials were subjected to quantitative analysis. Active stimulation demonstrated significant reductions of core posttraumatic symptoms with a large effect size (Hedge's g = -0.975). Subgroup analysis showed that both excitatory and inhibitory rTMS of the right dorsolateral prefrontal cortex led to symptom reductions with a large (Hedges' g = -1.161, 95% CI, -1.823 to -0.499; p = 0.015) and medium effect size (Hedges' g = -0.680, 95% CI: -0.139 to -0.322; p ≤ 0.001) respectively. Results further indicated significant durability of symptom-reducing effects of treatments during a two to four weeks period post stimulation (Hedges' g = -0.909, 95% CI: -1.611 to -0.207; p = 0.011). rTMS of the right dorsolateral prefrontal cortex appears to have a positive effect in reducing core symptoms in patients with posttraumatic stress disorder.

Neurostimulation in Anxiety Disorders, Post-traumatic Stress Disorder, and Obsessive-Compulsive Disorder

Many pharmacological treatments were proved effective in the treatment of panic disorder (PD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), post-traumatic stress disorder (PTSD), and obsessive-compulsive disorder (OCD); still many patients do not achieve remission with these treatments. Neurostimulation techniques have been studied as promising alternatives or augmentation treatments to pharmacological and psychological therapies. The most studied neurostimulation method for anxiety disorders, PTSD, and OCD was repetitive transcranial magnetic stimulation (rTMS). This neurostimulation technique had the highest level of evidence for GAD. There were also randomized sham-controlled trials indicating that rTMS may be effective in the treatment of PTSD and OCD, but there were conflicting findings regarding these two disorders. There is indication that rTMS may be effective in the treatment of panic disorder, but the level of evidence is low. Deep brain stimulation (DBS) was most studied for treatment of OCD, but the randomized sham-controlled trials had mixed findings. Preliminary findings indicate that DBS could be affective for PTSD. There is weak evidence indicating that electroconvulsive therapy, transcranial direct current stimulation, vagus nerve stimulation, and trigeminal nerve stimulation could be effective in the treatment of anxiety disorders, PTSD, and OCD. Regarding these disorders, there is no support in the current literature for the use of neurostimulation in clinical practice. Large high-quality studies are warranted.

Mild traumatic brain injury impacts associations between limbic system microstructure and post-traumatic stress disorder symptomatology

BACKGROUND

Post-traumatic stress disorder (PTSD) is a psychiatric disorder that afflicts many individuals, yet the neuropathological mechanisms that contribute to this disorder remain to be fully determined. Moreover, it is unclear how exposure to mild traumatic brain injury (mTBI), a condition that is often comorbid with PTSD, particularly among military personnel, affects the clinical and neurological presentation of PTSD. To address these issues, the present study explores relationships between PTSD symptom severity and the microstructure of limbic and paralimbic gray matter brain regions, as well as the impact of mTBI comorbidity on these relationships.

METHODS

Structural and diffusion MRI data were acquired from 102 male veterans who were diagnosed with current PTSD. Diffusion data were analyzed with free-water imaging to quantify average CSF-corrected fractional anisotropy (FA) and mean diffusivity (MD) in 18 limbic and paralimbic gray matter regions. Associations between PTSD symptom severity and regional average dMRI measures were examined with repeated measures linear mixed models. Associations were studied separately in veterans with PTSD only, and in veterans with PTSD and a history of military mTBI.

RESULTS

Analyses revealed that in the PTSD only cohort, more severe symptoms were associated with higher FA in the right amygdala-hippocampus complex, lower FA in the right cingulate cortex, and lower MD in the left medial orbitofrontal cortex. In the PTSD and mTBI cohort, more severe PTSD symptoms were associated with higher FA bilaterally in the amygdala-hippocampus complex, with higher FA bilaterally in the nucleus accumbens, with lower FA bilaterally in the cingulate cortex, and with higher MD in the right amygdala-hippocampus complex.

CONCLUSIONS

These findings suggest that the microstructure of limbic and paralimbic brain regions may influence PTSD symptomatology. Further, given the additional associations observed between microstructure and symptom severity in veterans with head trauma, we speculate that mTBI may exacerbate the impact of brain microstructure on PTSD symptoms, especially within regions of the brain known to be vulnerable to chronic stress. A heightened sensitivity to the microstructural environment of the brain could partially explain why individuals with PTSD and mTBI comorbidity experience more severe symptoms and poorer illness prognoses than those without a history of brain injury. The relevance of these microstructural findings to the conceptualization of PTSD as being a disorder of stress-induced neuronal connectivity loss is discussed.