Antidepressant response to aripiprazole augmentation associated with enhanced FDOPA utilization in striatum: a preliminary PET study

Antidepressant-like Effects of Representative Types of Food and Their Possible Mechanisms

Depression is a mental disorder characterized by low mood, lack of motivation, negative cognitive outlook, and sleep problems. Suicide may occur in severe cases, although suicidal thoughts are not seen in all cases. Globally, an estimated 350 million individuals grapple with depression, as reported by the World Health Organization. At present, drug and psychological treatments are the main treatments, but they produce insufficient responses in many patients and fail to work at all in many others. Consequently, treating depression has long been an important topic in society. Given the escalating prevalence of depression, a comprehensive strategy for managing its symptoms and impacts has garnered significant attention. In this context, nutritional psychiatry emerges as a promising avenue. Extensive research has underscored the potential benefits of a well-rounded diet rich in fruits, vegetables, fish, and meat in alleviating depressive symptoms. However, the intricate mechanisms linking dietary interventions to brain function alterations remain largely unexplored. This review delves into the intricate relationship between dietary patterns and depression, while exploring the plausible mechanisms underlying the impact of dietary interventions on depression management. As we endeavor to unveil the pathways through which nutrition influences mental well-being, a holistic perspective that encompasses multidisciplinary strategies gains prominence, potentially reshaping how we approach and address depression.

Neurophysiologic Effects of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) via Electrical Stimulation of the Tragus: A Concurrent taVNS/fMRI Study and Review

(Appeared originally in Brain Stimulation 2018; 11:492-500) Reprinted with permission from Elsevier.

Structural Plasticity Induced by Ketamine in Human Dopaminergic Neurons as Mechanism Relevant for Treatment-Resistant Depression

The mechanisms underlying the antidepressant effects of ketamine in treatment-resistant depression are only partially understood. Reactivation of neural plasticity in prefrontal cortex has been considered critical in mediating the effects of standard antidepressants, but in treatment-resistant depression patients with severe anhedonia, other components of the affected brain circuits, for example, the dopamine system, could be involved. In a recent article in Molecular Psychiatry, we showed that ketamine induces neural plasticity in human and mouse dopaminergic neurons. Human dopaminergic neurons were differentiated from inducible pluripotent stem cells for over 60 days. Mimicking the pharmacokinetic exposures occurring in treatment-resistant depression subjects, cultures were incubated with either ketamine at 0.1 and 1 µM for 1 h or with its active metabolite (2R,6R)-hydroxynorketamine at 0.1 and 0.5 µM for up to 6 h. Three days after dosing, we observed a concentration-dependent increase in dendritic arborization and soma size. These effects were mediated by the activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor that triggered the pathways of mammalian target of rapamycin and extracellular signal-regulated kinase via the engagement of brain-derived neurotrophic factor signaling, as previously described in rodent prefrontal cortex. Interestingly, we found that neural plasticity induced by ketamine requires functionally intact dopamine D3 receptors. These data are in keeping with our recent observation that plasticity can be induced in human dopaminergic neurons by the D3 receptor-preferential agonist pramipexole, whose effect as augmentation treatment in treatment-resistant depression has been reported. Overall, the evidence of pharmacologic response in human inducible pluripotent stem cell-derived neurons could provide complementary information to those provided by circuit-based imaging when assessing the potential response to a given augmentation treatment.

The Potential Utility of Aripiprazole Augmentation for Major Depressive Disorder with Mixed Features Specifier: A Retrospective Study

Objective

The present study aimed to observe potential benefit of aripiprazole augmentation in the treatment of major depressive disorder with mixed specifier (MDDM) in naturalistic treatment setting.

Methods

Data were collected from MDDM patients using a retrospective chart review for 8 weeks (week –8 and week 0) in routine practice. All patients were on current antidepressants upon starting of aripiprazole. Patients were treated without restriction of doses of aripiprazole. The primary endpoint was the mean change of Montgomery–Åsberg Depression Rating Scale (MADRS) total scores along with various secondary endpoint measures.

Results

In total 38 patients were analyzed. The changes of MADRS, Clinical Global Impression (CGI)-severity, Young Mania Rating Scale, Sheehan Disability Scale, and CGI-clinical benefit total scores from baseline to the endpoint were −7.1, −0.8, −4.9, −4.1, and −3.6, respectively (all p < 0.0001). At the endpoint, the responder and remitter rates by MADRS score criteria were approximately 32% and 21%, respectively.

Conclusion

The present findings have clearly shown the effectiveness and tolerability of aripiprazole augmentation for MDDM patients in routine practice. The present study warrants subsequent, adequately-powered, well-controlled studies for generalizability near future.

Specific depressive symptoms predict remission to aripiprazole augmentation in late-life treatment resistant depression

OBJECTIVE

To identify which specific depressive symptoms predict remission to aripiprazole augmentation in late-life treatment resistant depression.

METHODS

This is a secondary analysis of data from a late-life treatment resistant depression trial examining the safety and efficacy of aripiprazole augmentation. Participants aged 60 and above were randomized to aripiprazole augmentation (N = 91) versus placebo (N = 90). The main outcome was depression remission. Clinical predictors included individual Montgomery-Asberg Depression Rating Scale (MADRS) item scores categorized as symptomatic (scores >2) or nonsymptomatic (scores ≤2).

RESULTS

Three MADRS items predicted depression remission with aripiprazole augmentation: symptomatic scores on sleep disturbance and nonsymptomatic scores on apparent sadness and inability to feel. The 2-way and 3-way interaction terms of these MADRS items were not significant predictors of remission; therefore, the models' ability to predict remission was not improved by combining the significant MADRS items.

CONCLUSIONS

The identification of specific depressive symptoms, which can be clinically assessed, can be used to inform treatment decisions. Older adults with treatment resistant depression that present with sleep disturbances, lack of apparent sadness, or lack of inability to feel should be considered for aripiprazole augmentation.

Neurophysiologic effects of transcutaneous auricular vagus nerve stimulation (taVNS) via electrical stimulation of the tragus: A concurrent taVNS/fMRI study and review

BACKGROUND

Electrical stimulation of the auricular branch of the vagus nerve (ABVN) via transcutaneous auricular vagus nerve stimulation (taVNS) may influence afferent vagal networks. There have been 5 prior taVNS/fMRI studies, with inconsistent findings due to variability in stimulation targets and parameters.

OBJECTIVE

We developed a taVNS/fMRI system to enable concurrent electrical stimulation and fMRI acquisition to compare the effects of taVNS in relation to control stimulation.

METHODS

We enrolled 17 healthy adults in this single-blind, crossover taVNS/fMRI trial. Based on parameters shown to affect heart rate in healthy volunteers, participants received either left tragus (active) or earlobe (control) stimulation at 500 μs 25 HZ for 60 s (repeated 3 times over 6 min). Whole brain fMRI analysis was performed exploring the effect of: active stimulation, control stimulation, and the comparison. Region of interest analysis of the midbrain and brainstem was also conducted.

RESULTS

Active stimulation produced significant increased BOLD signal in the contralateral postcentral gyrus, bilateral insula, frontal cortex, right operculum, and left cerebellum. Control stimulation produced BOLD signal activation in the contralateral postcentral gyrus. In the active vs. control contrast, tragus stimulation produced significantly greater BOLD increases in the right caudate, bilateral anterior cingulate, cerebellum, left prefrontal cortex, and mid-cingulate.

CONCLUSION

Stimulation of the tragus activates the cerebral afferents of the vagal pathway and combined with our review of the literature suggest that taVNS is a promising form of VNS. Future taVNS/fMRI studies should systematically explore various parameters and alternative stimulation targets aimed to optimize this novel form of neuromodulation.

The combination of escitalopram and aripiprazole: Investigation of psychomotor effects in rats

Pre-clinical and clinical evidence suggests that the antidepressant efficacy of the selective serotonin reuptake inhibitor escitalopram can be enhanced by the dopamine and serotonin partial agonist aripiprazole. Given the range of possible neurochemical interactions between these drugs, the current study investigated whether aripiprazole alters the hedonic and psychomotor effects of escitalopram. Male Sprague Dawley rats ( n=116) received 10 mg/kg/day escitalopram (subcutaneous), 2 mg/kg/day aripiprazole (subcutaneous), or combined aripiprazole + escitalopram, and were tested for consumption of incentive nutritional stimuli (high-fructose corn syrup and chow), stereotypy and locomotor activity. At the conclusion of behavioral testing, mRNAs of two genes involved in reward processes were quantified: hypothalamic pro-opiomelanocortin and hippocampal brain-derived neurotrophic factor. Escitalopram produced a selective, but temporary, decrease in high fructose corn syrup consumption that was not altered by aripiprazole co-administration. Escitalopram had no significant effect on locomotion, but aripiprazole co-administration produced a persistent increase in stereotypy. Both brain-derived neurotrophic factor and pro-opiomelanocortin mRNA levels were lower in the aripiprazole + escitalopram group relative to the escitalopram group. Taken together, these results suggest that aripiprazole may enhance the antidepressant efficacy of escitalopram through improvement of psychomotor functions.

Predictors and Moderators of Remission With Aripiprazole Augmentation in Treatment-Resistant Late-Life Depression: An Analysis of the IRL-GRey Randomized Clinical Trial

IMPORTANCE

Safe, efficacious, second-line pharmacological treatment options exist for the large portion of older adults with major depressive disorder who do not respond to first-line pharmacotherapy. However, limited evidence exists to aid clinical decision making regarding which patients will benefit from which second-line treatments.

OBJECTIVE

To test the moderating role of pretreatment executive function, severity of anxiety, and severity of medical comorbidity in remission of treatment-resistant late-life depression after aripiprazole augmentation.

DESIGN, SETTING, AND PARTICIPANTS

As follow-up to a 12-week randomized clinical trial of aripiprazole augmentation for first-line treatment-resistant late-life depression (Incomplete Response in Late-Life Depression: Getting to Remission [IRL-GRey]), we evaluated the effects of the following potential moderators and their interactions with treatment: baseline assessments of executive function (set shifting measured by the Trail Making Test) and response inhibition control (measured by a Color-Word Interference task), anxiety symptoms, and medical comorbidity. Analyses were conducted in May and June 2015.

INTERVENTIONS

Aripiprazole or placebo tablets were started at 2 mg daily and titrated as tolerated, to a maximal dose of 15 mg daily.

MAIN OUTCOMES AND MEASURES

Remission of treatment-resistant late-life depression (defined as a Montgomery-Åsberg Depression Rating Scale score of ≤10 at both of the last 2 consecutive visits).

RESULTS

Of 181 trial participants (103 female [56.9%]) who were 60 years of age or older and whose major depression had failed to remit with venlafaxine hydrochloride monotherapy, 91 received aripiprazole and 90 received placebo. Remission occurred in 40 (43%) who received aripiprazole and 26 (29%) who received placebo. Baseline set shifting moderated the efficacy of aripiprazole augmentation (odds ratio [OR], 1.66 [95% CI, 1.05-2.62]; P = .03 for interaction with treatment). Among participants with a Trail Making Test scaled score of 7 or higher, the odds of remission were significantly higher with aripiprazole than with placebo (53% vs 28%; number needed to treat, 4; OR, 4.11 [95% CI, 1.83-9.20]). Among participants with a Trail Making Test scaled score of less than 7, aripiprazole and placebo were equally efficacious (OR, 0.64 [95% CI, 0.15-2.80]). Greater severity of anxiety at baseline predicted a lower remission rate but did not moderate aripiprazole efficacy; each standard deviation greater anxiety severity was associated with 50% reduced odds of remission in both aripiprazole and placebo arms. Medical comorbidity and Color-Word Interference test performance were neither general predictors nor treatment-moderating factors.

CONCLUSIONS AND RELEVANCE

Set-shifting performance indicates which older adults with treatment-resistant depression may respond favorably to augmentation with aripiprazole and thus may help to personalize treatment.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00892047.

Efficacy, safety, and tolerability of augmentation pharmacotherapy with aripiprazole for treatment-resistant depression in late life: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Treatment-resistant major depression is common and potentially life-threatening in elderly people, in whom little is known about the benefits and risks of augmentation pharmacotherapy. We aimed to assess whether aripiprazole is associated with a higher probability of remission than is placebo.

METHODS

We did a randomised, double-blind, placebo-controlled trial at three centres in the USA and Canada to test the efficacy and safety of aripiprazole augmentation for adults aged older than 60 years with treatment-resistant depression (Montgomery Asberg Depression Rating Scale [MADRS] score of ≥15). Patients who did not achieve remission during a pre-trial with venlafaxine extended-release (150-300 mg/day) were randomly assigned (1:1) to the addition of aripiprazole (target dose 10 mg [maximum 15 mg] daily) daily or placebo for 12 weeks. The computer-generated randomisation was done in blocks and stratified by site. Only the database administrator and research pharmacists had knowledge of treatment assignment. The primary endpoint was remission, defined as an MADRS score of 10 or less (and at least 2 points below the score at the start of the randomised phase) at both of the final two consecutive visits, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00892047.

FINDINGS

From July 20, 2009, to Dec 30, 2013, we recruited 468 eligible participants, 181 (39%) of whom did not remit and were randomly assigned to aripiprazole (n=91) or placebo (n=90). A greater proportion of participants in the aripiprazole group achieved remission than did those in the placebo group (40 [44%] vs 26 [29%] participants; odds ratio [OR] 2·0 [95% CI 1·1-3·7], p=0·03; number needed to treat [NNT] 6·6 [95% CI 3·5-81·8]). Akathisia was the most common adverse effect of aripiprazole (reported in 24 [26%] of 91 participants on aripiprazole vs 11 [12%] of 90 on placebo). Compared with placebo, aripiprazole was also associated with more Parkinsonism (15 [17%] of 86 vs two [2%] of 81 participants), but not with treatment-emergent suicidal ideation (13 [21%] of 61 vs 19 [29%] of 65 participants) or other measured safety variables.

INTERPRETATION

In adults aged 60 years or older who do not achieve remission from depression with a first-line antidepressant, the addition of aripiprazole is effective in achieving and sustaining remission. Tolerability concerns include the potential for akathisia and Parkinsonism.

FUNDING

National Institute of Mental Health, UPMC Endowment in Geriatric Psychiatry, Taylor Family Institute for Innovative Psychiatric Research, National Center for Advancing Translational Sciences, and the Campbell Family Mental Health Research Institute.

Optimizing the Use of Aripiprazole Augmentation in the Treatment of Major Depressive Disorder: From Clinical Trials to Clinical Practice

Major depressive disorder (MDD) is a recurrent, chronic, and devastating disorder leading to serious impairment in functional capacity as well as increasing public health care costs. In the previous decade, switching therapy and dose adjustment of ongoing antidepressants was the most frequently chosen subsequent treatment option for MDD. However, such recommendations were not based on firmly proven efficacy data from well-designed, placebo-controlled, randomized clinical trials (RCTs) but on practical grounds and clinical reasoning. Aripiprazole augmentation has been dramatically increasing in clinical practice owing to its unique action mechanisms as well as proven efficacy and safety from adequately powered and well-controlled RCTs. Despite the increased use of aripiprazole in depression, limited clinical information and knowledge interfere with proper and efficient use of aripiprazole augmentation for MDD. The objective of the present review was to enhance clinicians' current understanding of aripiprazole augmentation and how to optimize the use of this therapy in the treatment of MDD.

Altered serotonin and dopamine transporter availabilities in brain of depressed patients upon treatment with escitalopram: A [123 I]β-CIT SPECT study

Altered SERT and DAT availabilities during treatment with escitalopram were investigated with [(123)I]2β-carbomethoxy-3β-(4-iodophenyl)tropane (β-CIT) SPECT in a series of patients fulfilling the criteria for unipolar major depressive disorder (MDD). 27 patients (10m, 42±16y) with diagnosis of MDD were recruited for the study. All patients underwent neuropsychiatric testing for assessment of Hamilton Depression (HAM-D) and Beck Depression Inventory (BDI) scores. At baseline, [(123)I]β-CIT SPECT recordings were acquired 4h (SERT-weighted) and 20-24h p.i (DAT-weighted). Follow-up scans and neuropsychiatric testing were performed after six weeks of stable escitalopram medication. Voxel-wise parametric maps of specific/ non-specific ratios-1 (~BPND) were calculated. At baseline, DAT-weighted BPND was 5.06±0.81 in striatum and SERT-weighted BPND was 0.94±0.18 in thalamus. There were significant negative correlations with age for DAT in striatum (R=-0.60; p<0.01) and SERT in thalamus (R=-0.45; p<0.05). Under SSRI treatment there was an apparent 42% occupancy of SERT in thalamus (p<0.0001), whereas DAT availability increased significantly by 20% in striatum (p<0.001); higher apparent SERT occupancy in thalamus was associated with lesser DAT increase in striatum (R=-0.62; p<0.005). The low apparent SERT occupancy may be confounded by alterations in SERT expression during treatment. Thus, [(123)I]β-CIT SPECT revealed age-dependent declines in DAT and SERT availabilities in un-medicated MDD patients, comparable to that seen previously in healthy controls. At follow-up, the SSRI-evoked increase in DAT was less pronounced in the older patients, even though apparent SERT occupancy and clinical improvement were not age-dependent. Present findings may have implications for escitalopram dosage and side effect profile in younger MDD patients.

A pilot randomized placebo-controlled trial of adjunctive aripiprazole for chronic PTSD in US military Veterans resistant to antidepressant treatment

Many individuals with post-traumatic stress disorder (PTSD) experience persistent symptoms despite pharmacological treatment with antidepressants. Several open-label monotherapy and adjunctive studies have suggested that aripiprazole (a second-generation antipsychotic) may have clinical utility in PTSD. However, there have been no randomized placebo-controlled trials of aripiprazole use for PTSD. We thus conducted a pilot randomized controlled trial of adjunctive aripiprazole versus placebo among Veterans with chronic PTSD serving in the US military since 11 September 2001 to assess the feasibility, safety, tolerability, and therapeutic potential of aripiprazole. Sixteen Veterans were randomized, and 14 completed at least 4 weeks of the study; 12 completed the entire 8-week trial. Outcome measures included the Clinician-Administered PTSD Scale (CAPS), PTSD Checklist, Beck Depression Inventory, Second Edition, and Positive and Negative Syndrome Scale scores. Aripiprazole was well-tolerated in this cohort, and improvements in CAPS, PTSD Checklist, Beck Depression Inventory, Second Edition, and Positive and Negative Syndrome Scale scores were as hypothesized. Although CAPS change scores did not reach statistical significance, aripiprazole outperformed placebo by 9 points on the CAPS in the last observation carried forward analysis compared with the placebo group (n = 7 per group), and by 20 points in the group randomized to aripiprazole that completed the entire study (n = 5) compared with the placebo group (n = 7). Results suggest promise for aripiprazole as an adjunctive strategy for the treatment of PTSD.