N-acetylcysteine augmentation therapy for moderate-to-severe obsessive-compulsive disorder: randomized, double-blind, placebo-controlled trial

New horizons for obsessive-compulsive disorder drug discovery: is targeting glutamate receptors the answer?

INTRODUCTION

Over the past decade, glutamate has emerged as a prominent focus in the field of obsessive-compulsive disorder (OCD) pathophysiology. A convergence of evidence from genetic, preclinical, and clinical studies points to glutamatergic dysfunction as a key feature of this condition. In light of these findings, there has been a growing interest in exploring the potential of glutamatergic agents in the treatment of OCD.

AREAS COVERED

This paper reviews the literature on glutamate transmission in OCD. In addition, the authors examine the results of clinical trials investigating the efficacy of glutamatergic agents in the treatment of OCD patients.

EXPERT OPINION

Along with the recognition of neuroinflammation in the brain in OCD, the evidence of glutamate dysfunction represents one of the most promising recent discoveries for understanding the mechanisms involved in OCD. The importance of this discovery lies primarily in its pharmacological implications and has led to intense research activity in the field of glutamatergic agents. While this research has not yet had a substantial clinical impact, targeting glutamate receptors remains a promising horizon for the successful treatment of OCD patients.

Nutritional and Wellness Strategies for Neurological and Psychiatric Recovery From Post-COVID Syndrome and Post-acute Sequelae of COVID-19

The post-COVID syndrome was officially recognized as a disability under the Americans with Disabilities Act, indicating that this syndrome has made a significant impact on our populace. Also, post-acute sequelae of COVID-19 (PASC) is a term that describes the long-term health problems that some people experience after being infected with the virus that causes COVID-19. These problems can last for weeks, months, or even years, and can affect various parts of the body, such as the heart, lungs, brain, and blood vessels. This narrative review paper utilized the PubMed database to explore the pathophysiology of post-COVID syndrome's neurological and psychiatric symptoms and PASC and make therapeutic connections to the known mechanisms of various nutritional, supplemental, and wellness approaches. Searches were queried on the PubMed database between March 29 and April 16, 2022, using the phrases "long-covid," "post-COVID syndrome," "Vitamin D covid," "vitamin C covid," "omega-3 covid," "kynurenine covid," "whole-body hyperthermia," "mushrooms immunity," "n-acetyl cysteine covid," "mushrooms cognition," "sugar consumption inflammation," and "covid microbiome." Articles were screened for their relevance to the discussion of post-COVID syndrome's neurological and psychiatric pathophysiology at the discretion of the principal researcher. There were no limitations regarding publication years, but articles from 2005 to April 2022 were cited. Micro-ischemic disease, neuropathy, autoimmune processes, mast-cell activation, and impaired blood-brain barriers have all been implicated in the pathological processes of this syndrome with varying degrees of supportive evidence. The common denominators, however, are inflammation and oxidative stress. Therefore, a beneficial approach to dealing with the complications of post-COVID syndrome would be to reduce the exacerbations of these common denominators with lifestyle and nutritional changes. Replenishing nutritional deficiencies, supplementing with N-acetylcysteine, decreasing consumption of refined sugars, preventing dysbiosis of the microbiome, performing exercises, increasing dietary intake of mushrooms, utilizing beneficial herbs such as rosemary, and increasing the core body temperature through whole-body hyperthermia seem to show potential for efficacy in this pursuit. Considering the safety and evidence-based connections of the therapies explored for dealing with the post-Covid syndrome, it could be of great benefit and of little harm to our patients to include these considerations in formulating post-Covid treatment plans.

Clinical Recommendations for Augmentation Agents in Obsessive-Compulsive Disorder Partially Responsive to Serotonin Reuptake Inhibitors

BACKGROUND

Obsessive-compulsive disorder (OCD) affects 2% to 3% of adults worldwide. Although serotonin reuptake inhibitors (SRIs) reliably demonstrate efficacy for this condition, 40% to 60% of patients only achieve partial recovery. The purpose of this systematic review was to assess the efficacy of other agents that may be used as augmentation agents for patients who are partial responders to SRI monotherapy.

METHODS

Using PRISMA-P guidelines, PubMed and Embase were searched using the randomized controlled trial (RCT) filter and the key word "obsessive-compulsive disorder." To be considered for analysis, a potential augmentation agent needed to have at least 2 RCTs. This review specifically analyzes the effect of each augmentation agent on OCD symptoms as measured by the Yale-Brown Obsessive-Compulsive Scale.

RESULTS

The augmentation agents analyzed in this review are d-cycloserine (2 RCTs), memantine (4 RCTs), N-acetylcysteine (5 RCTs), lamotrigine (2 RCTs), topiramate (3 RCTs), riluzole (2 RCTs), ondansetron (2 RCTs), celecoxib (2 RCTs), aripiprazole (5 RCTs), risperidone (7 RCTs), quetiapine (9 RCTs), and olanzapine (3 RCTs).

IMPLICATIONS

The augmentation agents most supported by this review for OCD that is only a partial response to SRI monotherapy are lamotrigine, memantine, and aripiprazole. If an antipsychotic must be used and aripiprazole is not tolerated, risperidone may be considered as an alternative. Unlike the SRI class effect for OCD symptom reduction, augmentation agents demonstrate considerable intraclass variability.

Pharmacological augmentation of serotonin reuptake inhibitors in patients with obsessive-compulsive disorder: A network meta-analysis

OBJECTIVES

The augmentation of serotonin reuptake inhibitors (SRIs) can be achieved by add-on therapy with different pharmacological agents in obsessive-compulsive disorder (OCD) for a better clinical outcome. This network meta-analysis (NMA) was conducted to evaluate and compare the effects of available augmentation agents for SRIs in OCD.

METHOD

The data was extracted from 59 relevant clinical trials after a literature search on MEDLINE/PubMed, Scopus, Cochrane databases and clinical trial registries. PRISMA guidelines were followed in data extraction, analysis and reporting. Random effects Bayesian NMA was done to pool the effects across the interventions for the change in Yale-Brown Obsessive-Compulsive Scale (YBOCS) scoring from baseline to the end of the study. Network graph was built, consistency model was run, node splitting analysis was performed, treatments were ranked as per SUCRA score and meta-regression was done for refractoriness to SRIs and duration of augmentation therapy as the predictor variables.

RESULTS

The drugs showing significant reduction in YBOCS scoring were pregabalin (MD:-8.1;95% CrI: -16, -0.43), memantine (MD:-6.2;95% CrI: -9.9, -2.3), lamotrigine (MD:-6;95% CrI: -12, -0.47), ondansetron (MD:-5.7;95% CrI: -11, -0.67), granisetron (MD:-5.6;95% CrI: -11, -0.44), aripiprazole (MD:-5.4;95% CrI:-9.1, -1.6), risperidone (MD:-3.3;95% CrI: -6.4, -0.20) and topiramate (MD:-5.3;95% CrI: -9.6, -0.97). The node-split analysis showed that direct and indirect pooled effect sizes for all comparisons were comparable. Meta-regression showed a statistically non-significant association between YBOCS score reduction with the duration of augmentation therapy, but significant with SRI-refractory status. Finally, the results were sorted based on certainty of evidence.

CONCLUSION

Memantine was found to be most effective augmentation agent for SRIs in OCD, followed by lamotrigine, ondansetron and granisetron with moderate certainty of evidence. The augmentation agents showed better symptom reduction in patients with SRI-refractory OCD in comparison to non-refractory OCD.

PROSPERO REGISTRATION

CRD42022360110.

Treatment-resistant OCD: Pharmacotherapies in adults

Serotonin reuptake inhibitor (SRI) medications are well established as first-line pharmacotherapeutic treatment for Obsessive-Compulsive Disorder (OCD). However, despite the excellent safety profile and demonstrated efficacy of these medications, a substantial proportion of individuals with OCD fail to attain sufficient benefit from SRIs. In this narrative review, we discuss clinical features of OCD that have been associated with poorer response to SRIs, and we present pharmacotherapeutic interventions that have been explored as augmenting or alternative treatments for treatment-resistant OCD. We additionally highlight non-SRI interventions for OCD that are currently under investigation. Pharmacotherapeutic interventions were identified via expert consensus. To assess the evidence base for individual pharmacotherapies, targeted searches for relevant English-language publications were performed on standard biomedical research databases, including MEDLINE. Information relevant to ongoing registered clinical trials in OCD was obtained by search of ClinicalTrials.gov. Pharmacotherapies are grouped for review in accordance with the general principles of Neuroscience-based Nomenclature (NbN). Clinical features of OCD that may suggest poorer response to SRI treatment include early age of onset, severity of illness, duration of untreated illness, and the presence of symmetry/ordering or hoarding-related symptoms. Based on evolving pathophysiologic models of OCD, diverse agents engaging serotonin, dopamine, norepinephrine, glutamate, and anti-inflammatory pathways have been explored as alternative or adjunctive therapies for treatment-resistant OCD and have at least preliminary evidence of efficacy. Medications with dopamine antagonist activity remain the most robustly evidence-based of augmenting interventions, yet dopamine antagonists benefit only a minority of those who try them and carry elevated risks of adverse effects. Interventions targeting glutamatergic and anti-inflammatory pathways are less well evidenced, but may offer more favorable benefit to risk profiles. Ongoing research should explore whether specific interventions may benefit individuals with particular features of treatment-resistant OCD.

Adjuvant palmitoylethanolamide therapy with risperidone improves negative symptoms in patients with schizophrenia: A randomized, double-blinded, placebo-controlled trial

BACKGROUND

Primary negative symptoms of schizophrenia are usually resistant to monotherapy with antipsychotics. The present study sought to assess the efficacy and tolerability of Palmitoylethanolamide (PEA) adjunctive therapy in treatment of negative symptoms in patients with stable schizophrenia.

METHODS

This 8-week (trial timepoints: baseline, week 4, week 8), double-blind, placebo-controlled clinical trial randomized patients with schizophrenia in a 1:1 ratio to compare the efficacy and safety of 600 mg twice a day of PEA and matched placebo alongside a stable dose of risperidone. Outcome measures were the positive and the negative syndrome scale (PANSS), the extrapyramidal symptom rating scale (ESRS), and the Hamilton depression rating scale (HDRS). The primary outcome was change in the negative subscale score during the trial period between the groups. Safety of interventions were controlled and addressed during the trial.

RESULTS

A total of 50 participants completed the trial (25 in each group). Baseline characteristics of the groups were comparable (p>0.05). There was significant effect from time-treatment interaction on negative symptoms (p = 0.012) suggesting greater symptom improvement in the PEA group. In contrast, the longitudinal changes in positive symptoms and depressive symptoms were similar between groups (p values>0.05). Safety assessments showed no significant difference regarding extrapyramidal symptoms, measured by ESRS, and also frequency of other complications between PEA and placebo groups (p values>0.05).

CONCLUSIONS

Adjunctive therapy with PEA and risperidone alleviates schizophrenia-related primary negative symptoms in a safe manner.

Efficacy and safety of palmitoylethanolamide as an adjunctive treatment for acute mania: A randomized, double-blind, placebo-controlled trial

AIM

Palmitoylethanolamide is an endogenous fatty acid amide with neuroprotective and anti-inflammatory actions. We performed a randomized, double-blind, placebo-controlled clinical trial to investigate the efficacy and safety of palmitoylethanolamide combination therapy in acute mania.

METHODS

Patients in the acute phase of mania were assigned into two parallel groups given either lithium (blood level of 0.8-1.1 mEq/L) and risperidone 3 mg plus palmitoylethanolamide 600 mg or placebo twice per day for 6 weeks. All participants were assessed with the Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale (HDRS), and Extrapyramidal Symptom Rating Scale (ESRS) at baseline and at weeks 1, 2, 4, and 6.

RESULTS

A total of 63 patients (32 in palmitoylethanolamide and 31 in placebo groups) completed the trial. We found a significant effect for time×treatment interaction on the YMRS score (F = 5.22, d.f. = 2.34, P= 0.004) from baseline to study end point. Results from independent t test showed a significantly greater decrease in YMRS scores in the palmitoylethanolamide group, compared with the placebo group, from baseline to weeks 4 and 6 (P= 0.018 and P= 0.002, respectively). There was no significant difference between palmitoylethanolamide and placebo groups based on ESRS scores or ESRS changes in scores (P>0.05).

CONCLUSIONS

Our findings provide preliminary evidence that palmitoylethanolamide is an effective adjunctive medication that improves manic symptoms and overall clinical status in acute episodes of mania. However, larger sample sizes and more extended follow-up therapy are needed in future studies to confirm our findings.

Evidence for Anti-inflammatory Effects of Adalimumab in Treatment of Patients With Major Depressive Disorder: A Pilot, Randomized, Controlled Trial

BACKGROUND

Literature has suggested that major depressive disorder (MDD) is accompanied by higher concentrations of inflammatory biomarkers, which could sabotage response to conventional treatments.

AIMS

This study aimed to evaluate the efficacy and safety of adalimumab adjunct to sertraline in adults with MDD and increased levels of systemic inflammation.

METHODS

In a 6-week, randomized, double-blind, placebo-controlled trial, 36 patients with MDD and high-sensitivity C-reactive protein ≥3 mg/L were equally assigned to receive sertraline plus either adalimumab or placebo. Participants were assessed using the Hamilton Depression Rating Scale (HAM-D) at baseline, week 3, and week 6. Moreover, serum concentrations of inflammatory biomarkers were measured at baseline and trial end point. Finally, patients were assessed for any adverse event during the trial.

RESULTS

Fifteen patients in each group completed the trial course. All baseline characteristics of participants were similar between the groups. Adalimumab adjunct to sertraline resulted in a greater improvement in HAM-D score compared with placebo over the trial period ( P < 0.001). Participants receiving adalimumab significantly experienced greater response to treatment (≥50% reduction in the HAM-D score) than those receiving placebo ( P = 0.042). Furthermore, after 6 weeks of adalimumab combination therapy with sertraline, inflammatory biomarkers significantly decreased ( P ≤ 0.001), whereas no significant alteration was found in the placebo group. No serious adverse event was documented in the treatment arms.

CONCLUSIONS

Adalimumab adjunctive therapy remarkably improves depressive symptoms of patients with MDD. Further investigations with larger sample sizes and longer follow-up periods are required to confirm the findings.

N-acetyl cysteine (NAC) augmentation in the treatment of obsessive-compulsive disorder: A phase III, 20-week, double-blind, randomized, placebo-controlled trial

OBJECTIVE

Preliminary evidence has suggested that adjunctive N-acetylcysteine (NAC), an antioxidant precursor to glutathione, may reduce symptoms of obsessive-compulsive disorder (OCD). We conducted a 20-week, multi-site, randomized controlled trial to investigate the safety and efficacy of the adjunctive use of NAC in OCD.

METHODS

The study was a phase III, 20-week, double-blind, randomized controlled trial across multiple sites in Australia investigating 2 g to 4 g per day of NAC (titrated according to response) in 98 participants with DSM-5 diagnosed OCD. Data were analysed using linear mixed effects models for the 89 participants who attended at least one follow-up visit.

RESULTS

A modified intention-to-treat analysis of the primary outcome found no evidence that NAC reduced symptoms of OCD measured on the Yale-Brown Obsessive-Compulsive Scale, relative to placebo (mean difference at week 20 = 0.53, 95% compatibility interval = -2.18, 3.23; p = 0.70; favouring placebo). There was also no evidence that NAC, compared to placebo, improved outcomes on the secondary measures including anxiety, depression, quality of life, functioning, or clinician/participant impression. NAC was well-tolerated with only mild gastrointestinal adverse events associated with the treatment.

CONCLUSION

We found no evidence supporting the efficacy of the adjunctive use of NAC in OCD.

Mitochondrial modulators for obsessive-compulsive and related disorders: a systematic review and meta-analysis

It remains unclear whether mitochondrial modulators (MMs) are beneficial in the treatment of obsessive-compulsive and related disorders. Thus, in an attempt to answer this clinical question, we performed a systematic review and a random-effects meta-analysis of double-blind, randomized, placebo-controlled trials. The primary outcome was change in overall symptoms as measured using standardized rating scales. Other outcomes were response to treatment; improvement in anxiety-related scales scores, depression-related scale scores, Clinical Global Impression Severity Scale (CGI-S) scores, and Sheehan Disability Scale (SDS) scores; all-cause discontinuation; and individual adverse events. We calculated the standardized mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. We reviewed 17 studies (n = 629, 72.62% female; duration = 2-20 weeks; mean age = 30.47 years) of MMs: eicosapentaenoic acid (K = 1), folic acid (K = 1), lithium (K = 1), N-acetylcysteine (K = 10), inositol (K = 3), and silymarin (K = 1). MMs outperformed placebo in overall improvement in symptoms (p < 0.01) and in improving anxiety-related scale scores (p = 0.05). Subgroup analysis of individual MMs revealed that although overall symptoms were better improved by N-acetylcysteine (p < 0.01) and lithium (p = 0.04), no MMs outperformed placebo in terms of improving anxiety-related scale scores. Neither pooled nor individual MMs outperformed placebo in improving response to treatment, depression-related scale scores, CGI-S scores, SDS scores, or all-cause discontinuation. N-acetylcysteine was no more associated with a higher incidence of individual adverse events including gastrointestinal symptoms, than placebo. In conclusion, N-acetylcysteine was beneficial in the treatment of obsessive-compulsive and related disorders. However, further study with larger samples is necessary to confirm this finding.

Risperidone combination therapy with adalimumab for treatment of chronic schizophrenia: a randomized, double-blind, placebo-controlled clinical trial

This study aimed to investigate the efficacy and safety of antitumor necrosis factor-alpha (TNF-α) therapy using adalimumab in patients with chronic schizophrenia. This is a randomized, double-blind, placebo-controlled clinical trial carried out at Roozbeh Hospital (Tehran, Iran) from June 2020 to October 2021. The patients were randomly divided into two parallel adalimumab + risperidone and placebo + risperidone groups. Participants in the intervention group received adalimumab subcutaneous injection (40 mg) by pen-injector at weeks 0 and 4. Using the Positive and Negative Symptoms Scale (PANSS), patients' positive and negative symptoms were assessed at weeks 0, 4, and 8. Forty patients (20 in each group) were included. PANSS total (t = 4.43, df = 38, P < 0.001), negative (t = 2.88, df = 38, P = 0.006), and general psychopathology (t = 4.06, df = 38, P < 0.001) scores demonstrated a significantly greater decline in adalimumab compared with the placebo group from baseline study endpoint. However, improvement of PANSS positive subscale scores showed no significant difference from the baseline study endpoint. There was no significant between-group difference regarding levels of C-reactive protein, interleukin (IL)-1β, TNF-α, IL-6, and IL-8 at baseline and also at the week 8 visit (P > 0.05 for all). The current study found adalimumab adjunctive therapy effective in treating schizophrenia, particularly its negative and general psychopathology symptoms, with no side effects.

Memantine augmentation of sertraline in the treatment of symptoms and executive function among patients with obsessive-compulsive disorder: A double-blind placebo-controlled, randomized clinical trial

BACKGROUND

Medications currently recommended for the treatment of Obsessive-Compulsive Disorder (OCD) usually decrease the severity of the symptoms by 20-30%; however, 40-60% of OCD patients do not achieve a satisfactory response. Our main objective was to investigate the effectiveness of memantine, a non-competitive N-Methyl-D-aspartate (NMDA) receptor antagonist, as an adjunct therapy to sertraline, a selective serotonin reuptake inhibitor (SSRI), to improve severity of symptoms and executive function among patients with obsessive-compulsive disorder.

METHODS

Seventy patients with OCD according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, and a Yale-Brown obsessive compulsive scale (Y-BOCS) score of more than 21 were recruited to the study. They received sertraline (100 mg daily initially followed by 200 mg daily after week 4) and either memantine (10 mg twice daily) or placebo in a placebo controlled, double-blinded, parallel-group, clinical trial of 12 weeks. The primary outcome was OCD symptoms measured by the Y-BOCS. Moreover, executive function of participants was measured by the Wisconsin Card Sorting Test (WCST).

RESULTS

The total score, and obsession and compulsion subscales of Y-BOCS significantly dropped in both groups with no significant difference between the two groups. However, memantine group showed a greater response in the number of completed categories subscale of the WCST (p value<0.001). We did not observe any major adverse effects in any of the groups.

CONCLUSION

Memantine has an acceptable safety and tolerability in patients with OCD and might have a positive effect on their executive function. Nevertheless, the current results don`t support the efficacy of memantine as an adjunctive agent to sertraline for symptoms in patients with OCD.

TRIAL REGISTRATION

The trial was registered at the Iranian Registry of Clinical Trials on 04/10/2019 ( www.irct.ir ; IRCT ID: IRCT20170123032145N4).

The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders

N-acetyl-L-cysteine (NAC) is a compound of increasing interest in the treatment of psychiatric disorders. Primarily through its antioxidant, anti-inflammatory, and glutamate modulation activity, NAC has been investigated in the treatment of neurodevelopmental disorders, schizophrenia spectrum disorders, bipolar-related disorders, depressive disorders, anxiety disorders, obsessive compulsive-related disorders, substance-use disorders, neurocognitive disorders, and chronic pain. Whilst there is ample preclinical evidence and theoretical justification for the use of NAC in the treatment of multiple psychiatric disorders, clinical trials in most disorders have yielded mixed results. However, most studies have been underpowered and perhaps too brief, with some evidence of benefit only after months of treatment with NAC. Currently NAC has the most evidence of having a beneficial effect as an adjuvant agent in the negative symptoms of schizophrenia, severe autism, depression, and obsessive compulsive and related disorders. Future research with well-powered studies that are of sufficient length will be critical to better understand the utility of NAC in the treatment of psychiatric disorders.

The role of psychological distress in the relationship between lifestyle and compulsivity: An analysis of independent, bi-national samples

BACKGROUND

Poor mental health is a state of psychological distress that is influenced by lifestyle factors such as sleep, diet, and physical activity. Compulsivity is a transdiagnostic phenotype cutting across a range of mental illnesses including obsessive-compulsive disorder, substance-related and addictive disorders, and is also influenced by lifestyle. Yet, how lifestyle relates to compulsivity is presently unknown, but important to understand to gain insights into individual differences in mental health. We assessed (a) the relationships between compulsivity and diet quality, sleep quality, and physical activity, and (b) whether psychological distress statistically contributes to these relationships.

METHODS

We collected harmonized data on compulsivity, psychological distress, and lifestyle from two independent samples (Australian n = 880 and US n = 829). We used mediation analyses to investigate bidirectional relationships between compulsivity and lifestyle factors, and the role of psychological distress.

RESULTS

Higher compulsivity was significantly related to poorer diet and sleep. Psychological distress statistically mediated the relationship between poorer sleep quality and higher compulsivity, and partially statistically mediated the relationship between poorer diet and higher compulsivity.

CONCLUSIONS

Lifestyle interventions in compulsivity may target psychological distress in the first instance, followed by sleep and diet quality. As psychological distress links aspects of lifestyle and compulsivity, focusing on mitigating and managing distress may offer a useful therapeutic approach to improve physical and mental health. Future research may focus on the specific sleep and diet patterns which may alter compulsivity over time to inform lifestyle targets for prevention and treatment of functionally impairing compulsive behaviors.

Glutamatergic medications as adjunctive therapy for moderate to severe obsessive-compulsive disorder in adults: a systematic review and meta-analysis

BACKGROUND

Obsessive-compulsive disorder (OCD) is among the most disabling neuropsychiatric conditions characterized by the presence of repetitive intrusive thoughts, impulses, or images (obsessions) and/or ritualized mental or physical acts (compulsions). Serotonergic medications, particularly Selective Serotonin Reuptake Inhibitors (SSRIs), are the first-line treatments for patients with OCD. Recently, dysregulation of glutamatergic system has been proposed to be involved in the etiology of OCD. We designed this systematic review and meta-analysis to evaluate clinical efficacy of glutamatergic medications in patients with OCD, according to the guidelines of Cochrane collaboration.

METHOD

We searched Medline, Scopus, and Cochrane library without applying any language filter. Two of the authors independently reviewed search results for irrelevant and duplicate studies and extracted data and assessed methodological quality of the studies. We transformed data into a common rubric and calculated a weighted treatment effect across studies using Review Manager.

RESULTS

We found 476 references in 3 databases, and after exclusion of irrelevant and duplicate studies, 17 studies with total number of 759 patients with OCD were included. In the present review we found evidence for several drugs such as memantine, N-acetylcysteine (NAC), Minocycline, L-carnosine and riluzole. Glutamaterigic drug plus SSRIs were superior to SSRI+ Placebo with regard to Y-BOCS scale [standardized mean difference (SMD = - 3.81 95% CI = - 4.4, - 3.23).

CONCLUSION

Augmentation of glutamatergic medications with SSRIs are beneficial in obsessive-compulsive patients, no harmful significant differences in any safety outcome were found between the groups.

Lifestyle Interventions in the Treatment of Obsessive-Compulsive and Related Disorders: A Systematic Review

OBJECTIVE

Lifestyle medicine is increasingly important in psychiatry for its efficacy as a transdiagnostic treatment, its preventative potential, and its increased tolerability compared with first-line strategies. Although the impact of lifestyle medicine is strong across many psychiatric illnesses, our understanding of the effectiveness of lifestyle interventions in treating obsessive-compulsive and related disorders (OCRDs) is minimal. We aimed to conduct a systematic review examining the effect of lifestyle interventions (targeting diet, exercise, sleep, stress management, and tobacco/alcohol use) on OCRD symptoms.

METHODS

We systematically searched four electronic databases for published randomized controlled trials reporting on lifestyle interventions for OCRDs. We qualitatively synthesized results of eligible studies and calculated mean changes in symptom severity from baseline to end point and standardized between-group effect sizes.

RESULTS

We identified 33 eligible studies. Poor efficacy was noted across a number of rigorous dietary supplement interventions with some promising data in four (of six) studies regarding N-acetylcysteine for trichotillomania, skin picking, and obsessive-compulsive disorder. Stress management interventions, generally characterized by high risk of bias, reported mild effectiveness with greater effects noted for mind-body exercises (yoga) for obsessive-compulsive disorder. Greater improvements may be achieved when lifestyle intervention is adjunct to first-line treatments and delivered by facilitators.

CONCLUSIONS

Diet (particularly N-acetylcysteine) and stress management interventions seem promising avenues for OCRDs treatment. We present an action plan to move the lifestyle interventions for OCRDs field forward. Further high-quality lifestyle interventions are required to improve the certainty of findings and to inform clinical treatment guidelines.Review Registration Number: CRD42020151407.

Antiglutamatergic agents for obsessive-compulsive disorder: Where are we now and what are possible future prospects?

Recent data suggest that obsessive-compulsive disorder (OCD) is driven by an imbalance among the habit learning system and the goal-directed system. The frontostriatal loop termed cortico-striatal-thalamo-cortical (CSTC) circuitry loop is involved in habits and their dysfunction plays an important role in OCD. Glutamatergic neurotransmission is the principal neurotransmitter implicated in the CSTC model of OCD. Hyperactivity in the CSTC loop implies a high level of glutamate in the cortical-striatal pathways as well as a dysregulation of GABAergic transmission, and could represent the pathophysiology of OCD. Moreover, the dysregulation of glutamate levels can lead to neurotoxicity, acting as a neuronal excitotoxin. The hypothesis of a role of neurotoxicity in the pathophysiology of OCD clinically correlates to the importance of an early intervention for patients. Indeed, some studies have shown that a reduction of duration of untreated illness is related to an earlier onset of remission. Although robust data supporting a progression of such brain changes are not available so far, an early intervention could help interrupt damage from neurotoxicity. Moreover, agents targeting glutamate neurotransmission may represent promising therapeutical option in OCD patients.

Nutrition, Exercise, and Stress Management for Treatment and Prevention of Psychiatric Disorders. A Narrative Review Psychoneuroendocrineimmunology-Based

Psychoneuroendocrineimmunology (PNEI) brings together knowledge acquired since the 1930s from endocrinology, immunology, neuroscience, and psychology. With PNEI, a model of research and interpretation of health and disease is emerging, which sees the human body as a structured and interconnected unit, where the psychological and biological systems are mutually coordinated. In the PNEI view, many factors could influence mental health, with the endocrine system involved in mediating the effects of environmental stress on mental health and inflammation in the onset and course of psychiatric disorders as a result of individual and collective conditions and behaviors. Among these, nutrition is one way by which the environment impacts physiology: indeed, many pieces of research showed that several elements (e.g., probiotics, fish oil, zinc) have a positive effect on mental disorders thus being potentially augmentation agents in treatment. Still, physical activity can moderate depressive symptoms, while prolonged stress increases the risk of psychopathology. Taken together, the PNEI-based approach may inform prevention and treatment strategies, also in the field of mental health care.

N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)

OBJECTIVE

To review the clinical usefulness of N-acetylcysteine (NAC) as treatment or adjunctive therapy in a number of medical conditions. Use in Tylenol overdose, cystic fibrosis, and chronic obstructive lung disease has been well documented, but there is emerging evidence many other conditions would benefit from this safe, simple, and inexpensive intervention. Quality of Evidence. PubMed, several books, and conference proceedings were searched for articles on NAC and health conditions listed above reviewing supportive evidence. This study uses a traditional integrated review format, and clinically relevant information is assessed using the American Family Physician Evidence-Based Medicine Toolkit. A table summarizing the potential mechanisms of action for N-acetylcysteine in these conditions is presented. Main Message. N-acetylcysteine may be useful as an adjuvant in treating various medical conditions, especially chronic diseases. These conditions include polycystic ovary disease, male infertility, sleep apnea, acquired immune deficiency syndrome, influenza, parkinsonism, multiple sclerosis, peripheral neuropathy, stroke outcomes, diabetic neuropathy, Crohn's disease, ulcerative colitis, schizophrenia, bipolar illness, and obsessive compulsive disorder; it can also be useful as a chelator for heavy metals and nanoparticles. There are also a number of other conditions that may show benefit; however, the evidence is not as robust.

CONCLUSION

The use of N-acetylcysteine should be considered in a number of conditions as our population ages and levels of glutathione drop. Supplementation may contribute to reducing morbidity and mortality in some chronic conditions as outlined in the article.

Specialty knowledge and competency standards for pharmacotherapy for adult obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects approximately one person in 40 and causes substantial suffering. Evidence-based treatments can benefit many; however, optimal treatment can be difficult to access. Diagnosis is frequently delayed, and pharmacological and psychotherapeutic interventions often fail to follow evidence-based guidelines. To ameliorate this distressing situation, the International OCD Accreditation Task Force of the Canadian Institute for Obsessive-Compulsive Disorders has developed knowledge and competency standards for specialized treatments for OCD through the lifespan. These are foundational to evidence-based practice and will form the basis for upcoming ATF development of certification/accreditation programs. Here, we present specialty standards for the pharmacological treatment of adult OCD. We emphasize the importance of integrating pharmacotherapy with clear diagnosis, appreciation of complicating factors, and evidence-based cognitive behavioral therapy. Clear evidence exists to inform first- and second-line pharmacological treatments. In disease refractory to these initial efforts, multiple strategies have been investigated, but the evidence is more equivocal. These standards summarize this limited evidence to give the specialist practitioner a solid basis on which to make difficult decisions in complex cases. It is hoped that further research will lead to development of a clear, multi-step treatment algorithm to support each step in clinical decision-making.

N-acetylcysteine as a new prominent approach for treating psychiatric disorders

N-acetylcysteine (NAC) is a well-known and safe mucolytic agent, also used in patients with paracetamol overdose. In addition to these effects, recent preclinical and clinical studies have shown that NAC exerts beneficial effects on different psychiatric disorders. Many potential mechanisms have been proposed to underlie the therapeutic effects of NAC, including the regulation of several neurotransmitters, oxidative homeostasis, and inflammatory mediators. In this paper, we summarize the current knowledge on the ability of NAC to ameliorate symptoms and neuropathologies related to different psychiatric disorders, including attention deficit hyperactivity disorder, anxiety, bipolar disorder, depression, obsessive-compulsive disorder, obsessive-compulsive-related disorder, posttraumatic stress disorder, and schizophrenia. Although preclinical studies have shown a positive effect of NAC on animal models of psychiatric disorders, the clinical efficacy of NAC is not fully established. NAC remains a strong candidate for adjunct treatment for many psychiatric disorders, but additional preclinical and clinical studies are needed.

Obsessive-Compulsive Disorder With Rheumatological and Inflammatory Diseases: A Systematic Review

Obsessive-compulsive disorder (OCD) is a common mental illness that can significantly impair the patients' quality of life. Recent studies have shown that patients with this condition usually suffer from inflammatory or rheumatological comorbidities. However, the association between OCD's etiology and inflammation is still controversial. This review aims to explore the correlation between OCD and rheumatological as well as inflammatory disorders based on studies conducted in the last decade. A total of eight articles that were deemed eligible were included in the final assessment, involving 31,204 OCD patients from various countries. The most significant inflammatory biomarkers examined were tumor necrosis factor-alpha (TNF-α), interleukins, neutrophil-to-lymphocyte ratio (NLR), and cytokines. We concluded that the pathophysiology and etiology of OCD are strongly correlated with inflammatory biomarkers. This finding warrants future studies on the efficacy of anti-inflammatory agents to treat OCD, particularly in the early stages of the disease.

Investigational and Experimental Drugs to Treat Obsessive-Compulsive Disorder

Treatment-resistance is a frequent condition for obsessive-compulsive disorder (OCD). Over the past decades, a lot of effort has been made to address this issue, and several augmentation strategies of serotonergic drugs have been investigated. Antidopaminergic drugs are considered the first choice as augmentation strategy for treatment-resistant OCD patients, but they seem to work only for a subset of patients, and none of them have been officially approved for OCD. Recently, the role of glutamate and inflammation in OCD pathophysiology clearly emerged, and this has led to several investigations on glutamatergic and anti-inflammatory agents. Results seem promising but still inconclusive. Probiotic interventions (considered to modulate the immune systems and the brain activity) are gaining attention in several psychiatric fields but are still at their early stages in the OCD field. Research on new treatment approaches for OCD is moving forward, and more than one hundred interventional trials are ongoing around the world. While the vast majority of these trials involve neuromodulation and psychotherapeutic approaches, only a small proportion (around 20%) involve the investigation of new pharmacological approaches (tolcapone, nabilone, psilocybin, troriluzole, nitrous oxide, rituximab, naproxen, and immunoglobulins). Here, we provide a comprehensive review of investigational and experimental drugs to treat OCD.

Pharmacotherapeutic Strategies and New Targets in OCD

Effective pharmacological and psychotherapeutic treatments are well established for obsessive-compulsive disorder (OCD). Serotonin reuptake inhibitors (SRIs) are first-line treatment and are of benefit to about half of patients. Augmentation of SRI treatment with low-dose neuroleptics is an evidence-based second-line strategy. Specialty psychotherapy is also used as both first-line and second-line treatment and can benefit many. However, a substantial number of patients do not respond to these treatments. New alternatives are urgently needed. This review summarizes evidence for these established pharmacotherapeutic strategies, and for others that have been investigated in refractory disease but are not supported by the same level of evidence. We focus on three neurotransmitter systems in the brain: serotonin, dopamine, and glutamate. We summarize evidence from genetic, neuroimaging, animal model, and other lines of investigation that probe these three systems in patients with OCD. We also review recent work on predictors of response to current treatments. While many studies suggest abnormalities that may provide insight into the pathophysiology of the disorder, most studies have been small, and non-replication of reported findings has been common. Nevertheless, the gradual accrual of evidence for neurotransmitter dysregulation may in time lead the way to new pharmacological strategies.

Inflammation, Obsessive-Compulsive Disorder, and Related Disorders

Initial reports supporting the possibility of inflammation in the brain in obsessive-compulsive disorder (OCD) evolved from the models of Sydenham's Chorea, and Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcus (PANDAS), which implicated excessive autoimmune responses following exposure to group A B-hemolytic streptococcal infections. Subsequently, this model was expanded to Pediatric Autoimmune Neuropsychiatric Syndrome (PANS) which applied the same concept but included other infections. A critical shortcoming of this model was that it was attributable to a small minority of OCD cases. The relationship between inflammation and OCD was more broadly demonstrated through translocator protein (TSPO) positron emission tomography imaging, a method that detects gliosis, an important component of brain inflammation, in neuropsychiatric diseases, including morphological activation and proliferation of microglia and to some extent astroglia. This method identified greater TSPO binding in the cortico-striatal-thalamo-cortical circuit in OCD, providing a direct brain measure of an important component of inflammation. To identify OCD cases with prominent elevations in TSPO binding in clinical research settings with lower cost peripheral markers, a promising approach is to apply blood serum biomarkers of inflammatory molecules produced by activated microglia and astroglia (gliosis). Such measures may aid stratification in future clinical trials. Several inflammatory-modifying interventions, including celecoxib, minocycline, and n-acetylcysteine, have been tested as treatments in randomized double-blind placebo controlled clinical trials and there is a tendency toward positive results, although these medications are not optimized for brain penetration and sample sizes for most trials were small. Future clinical trials of medications that target gliosis in OCD should apply larger sample sizes, ideally incorporating stratification approaches to enrich samples for the presence of gliosis.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

5-Hydroxytryptophan as adjuvant therapy in treatment of moderate to severe obsessive-compulsive disorder: a double-blind randomized trial with placebo control

On the basis of numerous previous studies, the serotonergic system plays a role in the pathogenesis of obsessive-compulsive disorder (OCD) and effective agents in this pathway, such as 5-hydroxytryptophan, can potentially contribute to treatment of patients with this disorder. Evaluating the efficacy of 5-hydroxytryptophan in treating OCD was the aim of the present randomized, double-blind, placebo-controlled 12-week trial. In a 12-week, randomized double-blind study, 60 patients with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnosis of moderate to severe OCD and a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score of >21 were randomly assigned to receive either fluoxetine plus placebo or fluoxetine plus 5-hydroxytryptophan (100 mg twice daily). All patients, regardless of their treatment group, received fluoxetine at 20 mg/day for the initial 4 weeks of the study followed by 60 mg/day of fluoxetine for the rest of the trial course. Symptoms were assessed using the Y-BOCS at baseline and weeks 4, 8 and 12. General linear model repeated measure showed significant effects for time × treatment interaction on total Y-BOCS (F = 12.07, df = 2.29, P-value <0.001), obsession (F = 8.25, df = 1.91, P-value = 0.001) and compulsion subscale scores (F = 6.64, df = 2.01, P-value = 0.002). 5-Hydroxytryptophan augmentation therapy demonstrated higher partial and complete treatment response rate (P = 0.032 and P = 0.001, respectively) according to the Y-BOCS total scores. The results of this study confirm that 5-hydroxytryptophan may be effective as an augmentative agent in treatment of moderate-to-severe OCD.

Reduced anterior cingulate glutamate of comorbid skin-picking disorder in adults with obsessive-compulsive disorder

BACKGROUND

Obsessive Compulsive Disorder (OCD) is characterized by hyperactivity in a network of forebrain structures, including the anterior cingulate cortex (ACC). Convergent evidence suggests that glutamatergic dysfunction may contribute to the disorder. Skin picking disorder (SPD) was listed as one of the obsessive-compulsive and related disorders, which is often comorbid with OCD and share overlapping phenomenology and pathophysiology. However, potential confounding effects between the two diagnostic effects on neurotransmitter levels remain largely unexamined.

METHODS

We examined the pregenual anterior cingulate cortex (pACC) glutamate and other neurochemicals in 62 subjects using a single-voxel acquisition 1H MRS at 3Tesla; of these, 47 subjects yielded usable measurements of both glutamate and glutamine and were included in the analysis (17 medicated with OCD alone, 13 medicated with comorbid OCD + SPD, 17 healthy control).

RESULTS

OCD with comorbid SPD showed significantly lower pACC glutamate than in patients without SPD (p = 0.001) or control subjects (p = 0.035). OCD without SPD subjects showed pACC glutamate levels indistinguishable from controls (p = 0.501). In the OCD with SPD subjects, glutamate was correlated with Y-BOCS total score in female patients (n = 9, r = 0.69, p = 0.041).

LIMITATIONS

The main limitation of the study was the cross-sectional data. Our patients were on SSRI medication which may have modified the effect of SPD and OCD interaction on glutamate activity.

CONCLUSION

Our results suggest that alterations of the glutamatergic system may play an important role in the pathophysiology of a subgroup of OCD and reduced pACC glutamate may be a biomarker of a distinct subset of OCD patients.

Nutritional and herbal supplements in the treatment of obsessive compulsive disorder

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder that is characterised by obsessions and compulsions. The recommended treatments for OCD are cognitive– behavioural therapy using exposure and response prevention and/or pharmacotherapy. On the other hand, some nutritional and herbal supplements may be effective in the treatment of OCD. Nutritional and herbal supplements in OCD treatment will be reviewed in this paper. PubMed (Medline), Cochrane Library and Google Scholar databases were reviewed for the topic. There are some supplements that have been researched in OCD treatment studies such as vitamin D, vitamin B₁₂, folic acid, homocysteine, trace elements, N-acetyl cysteine, glycine, myoinositol, St John’s wort, milk thistle, valerian root, curcumin and borage. The effectiveness of herbal and nutritional supplements in the treatment of OCD should be supported with more conclusive evidence.

N-Acetylcysteine for Pediatric Obsessive-Compulsive Disorder: A Small Pilot Study

Background: Many children and adults with Obsessive-Compulsive Disorder (OCD) fail to respond to first-line pharmacological and behavioral treatments. Glutamate dysfunction may contribute to the development of OCD. N-acetylcysteine (NAC), a glutamate modulating drug, has shown to be a promising agent in adults with OCD. Methods: We conducted a double-blind, placebo-controlled clinical trial from July 2012 to January 2017. Children ages 8 to 17 years with OCD were assigned to receive NAC (up to 2700 mg/day) or the matching placebo for a period of 12 weeks. Children were required to be on stable psychiatric treatment (both medication and therapy) but were not required to be treatment-refractory. The primary outcome was OCD symptom severity as measured by the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). We used linear mixed models to analyze the effect of NAC compared to placebo. Results: Due to poor recruitment and eventual expiration of the study medication, enrollment was stopped at 11 children out of a planned sample size of 40. Nonetheless, NAC was associated with significant reduction in CY-BOCS total score compared to placebo (Satterthwaite's test: t (37) = 2.36, p = 0.024) with effects separating from placebo beginning at week 8. Mean CY-BOCS total score decreased in the NAC group from 21.4 ± 4.65 at baseline to 14.4 ± 5.55 at week 12. In the placebo group, mean CY-BOCS total score remained unchanged (21.3 ± 4.65). In the NAC group, 1 out of 5 participants achieved >35% improvement in CY-BOCS total score, while none of the six patients in placebo group reached this improvement level. NAC and placebo were well tolerated. One mild adverse event was reported in each group. Conclusions: Our trial suggests that there may be some initial improvement in OCD symptom severity with NAC treatment. NAC was well tolerated in the study population. Future trials should employ multiple sites and have a larger study population to further confirm any benefits of NAC.

Psychopharmacological Treatment of Obsessive-Compulsive Disorder (OCD)

Background:

Obsessive-compulsive disorder (OCD) is associated with affective and cognitive symptoms causing personal distress and reduced global functioning. These have considerable societal costs due to healthcare service utilization.

Objective:

Our aim was to assess the efficacy of pharmacological interventions in OCD and clinical guidelines, providing a comprehensive overview of this field.

Methods:

We searched the PubMed database for papers dealing with drug treatment of OCD, with a specific focus on clinical guidelines, treatments with antidepressants, antipsychotics, mood stabilizers, off-label medications, and pharmacogenomics.

Results:

Prolonged administration of selective serotonin reuptake inhibitors (SSRIs) is most effective. Better results can be obtained with a SSRI combined with cognitive behavioral therapy (CBT) or the similarly oriented exposure and response prevention (ERP). Refractory OCD could be treated with different strategies, including a switch to another SSRI or clomipramine, or augmentation with an atypical antipsychotic. The addition of medications other than antipsychotics or intravenous antidepressant administration needs further investigation, as the evidence is inconsistent. Pharmacogenomics and personalization of therapy could reduce treatment resistance.

Conclusions:

SSRI/clomipramine in combination with CBT/ERP is associated with the optimal response compared to each treatment alone or to other treatments. New strategies for refractory OCD are needed. The role of pharmacogenomics could become preponderant in the coming years.

Placebo Effect in Obsessive-Compulsive Disorder (OCD). Placebo Response and Placebo Responders in OCD: The Trend Over Time

BACKGROUND

Placebo response appears to be increasing in antidepressant, antipsychotic and various internal medicine trials. A similar trend has been reported for OCD during 1989-1999. Placebo response is generally considered as the extent to which placebo treatment is associated with core symptom improvement. In this analysis, we used Joinpoint regression to assess the time trend of both placebo response and placebo responder rates according to the year of publication with no time restriction in OCD drug trials.

METHODS

We included drug and/or psychotherapy trials vs. placebo from PubMed, Embase, CINAHL, and PsycINFO retrieved through the search (placebo OR sham) AND (obsessive* OR OCD). We included studies through investigator consensus. We then performed on data of included studies log-linear joinpoint segmented regression models using a p<0.05 cutoff.

RESULTS

We included 113 studies from 112 published papers. Placebo mean annual response rates in OCD studies significantly increased from 1991 to 2017 with an annual percent change (APC) of 0.66%, while placebo mean annual responder rates also significantly increased from 2010 to 2017, with an APC of 5.45%. Drug mean annual response rates in OCD studies significantly increased from 1987 to 2012 with an APC of 0.72%, while the corresponding responder rates did not show statistically significant APC changes between 1984 and 2017.

CONCLUSION

We observed a tendency for placebo to increase both measures of response in OCD clinical drug trials through the years that tend to approximate the responses shown by drugs. Changes in the type of study (moving from classical head to head comparisons to add-on studies in treatmentresistant populations) and countries involved in experimentation may partially account for some portion of these results. It appears that placebo effects are becoming more elusive and out of control.

Trichotillomania is more related to Tourette disorder than to obsessive-compulsive disorder

OBJECTIVE

Trichotillomania (TTM) is characterized by the pulling out of one's hair. TTM was classified as an impulse control disorder in DSM-IV, but is now classified in the obsessive-compulsive related disorders section of DSM-5. Classification for TTM remains an open question, especially considering its impact on treatment of the disorder. In this review, we questioned the relation of TTM to tic disorder and obsessive-compulsive disorder (OCD).

METHOD

We reviewed relevant MEDLINE-indexed articles on clinical, neuropsychological, neurobiological, and therapeutic aspects of trichotillomania, OCD, and tic disorders.

RESULTS

Our review found a closer relationship between TTM and tic disorder from neurobiological (especially imaging) and therapeutic standpoints.

CONCLUSION

We sought to challenge the DSM-5 classification of TTM and to compare TTM with both OCD and tic disorder. Some discrepancies between TTM and tic disorders notwithstanding, several arguments are in favor of a closer relationship between these two disorders than between TTM and OCD, especially when considering implications for therapy. This consideration is essential for patients.

Investigating the Role of Glutamate in Obsessive-Compulsive Disorder: Current Perspectives

Glutamate is a ubiquitous excitatory neurotransmitter, which is involved in normal physiology, a variety of central nervous system (CNS) functions, including excitotoxicity and neuronal migration. It is implicated in the pathogenesis of various neuropsychiatric disorders including epilepsy, Parkinson's disease, Alzheimer's dementia, schizophrenia and obsessive compulsive disorder (OCD). Over the years, a growing body of evidence has helped researchers understand the mechanisms underlying glutamatergic involvement in the pathogenesis of these disorders. In this review, we attempt to elucidate the role of glutamate in OCD, which is a chronic psychiatric condition with significant morbidity. This article provides current perspectives on the role played by glutamate in the pathogenesis, clinical symptoms and treatment response in OCD, a critical analysis of existing and emerging evidence, both clinical and preclinical, followed by a summary and future directions.

A systematic review and meta-analysis: Memantine augmentation in moderate to severe obsessive-compulsive disorder

A considerable proportion of obsessive-compulsive disorder (OCD) patients receiving first-line pharmacological therapy, fail to fully respond to treatment and continue to exhibit significant symptoms. In this systematic review, we evaluate the efficacy of memantine, as a glutamate-modulating agent, in moderate to severe OCD. Single and double blinded as well as open-label trials of memantine augmentation in adults with OCD were considered. Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores were the primary outcome measure. The electronic databases of PubMed, Scopus, Embase and Google Scholar were searched for relevant trials using keywords 'obsessive-compulsive disorder OR OCD' AND 'memantine'. The meta-analysis of eight studies involving 125 OCD subjects receiving memantine augmentation exhibited a significant overall mean reduction of 11.73 points in Y-BOCS scores. The categorical analysis of treatment response (a minimum of 35% reduction in Y-BOCS) in four double-blind placebo-controlled studies indicated that OCD patients receiving memantine augmentation were 3.61 times more likely to respond to treatment than those receiving placebo. We found that 20 mg/day memantine augmentation to first-line pharmacological treatment for a period of at least 8 weeks is a safe and effective intervention for moderate to severe OCD.

The psychopharmacology algorithm project at the Harvard South Shore Program: An algorithm for adults with obsessive-compulsive disorder

A previous algorithm for the pharmacological treatment of obsessive-compulsive disorder was published in 2012. Developments over the past 7 years suggest an update is needed. The authors conducted searches in PubMed, focusing on new studies and reviews since 2012 that would support or change previous recommendations. We identified exceptions to the main algorithm, including pregnant women and women of child-bearing potential, the elderly, and patients with common medical and psychiatric co-morbidities. Selective serotonin reuptake inhibitors (SSRIs) are still first-line. An adequate trial requires a period at typical antidepressant doses and dose adjustments guided by a plasma level to evaluate for poor adherence or ultra-rapid metabolism. If the response is inadequate, consider a trial of another SSRI this time possibly taken to a very high dose. Clomipramine could be an alternative. If the response to the second trial remains inadequate, the next recommendation is to augment with aripiprazole or risperidone. Alternatively, augmentation with novel agents could be selected, including glutamatergic (memantine, riluzole, topiramate, n-acetylcysteine, lamotrigine), serotonergic (ondansetron), and anti-inflammatory (minocycline, celecoxib) agents. A third option could be transcranial magnetic stimulation. Lastly, after several of these trials, deep brain stimulation and cingulotomy have evidence for a role in the most treatment-refractory patients.

A Systematic Review of Evidence-based Treatment Strategies for Obsessive- compulsive Disorder Resistant to first-line Pharmacotherapy

BACKGROUND

Serotonin reuptake inhibitors (SRIs) and cognitive-behavioral psychotherapy (CBT) are first-line treatments for obsessive-compulsive disorder (OCD). However, a significant proportion of patients do not respond satisfactorily to first-choice treatments. Several options have been investigated for the management of resistant patients.

OBJECTIVE

The aim of the present paper is to systematically review the available literature concerning the strategies for the treatment of resistant adult patients with OCD.

METHOD

We first reviewed studies concerning the definition of treatment-resistant OCD; we then analyzed results of studies evaluating several different strategies in resistant patients. We limited our review to double-blind, placebo-controlled studies performed in adult patients with OCD whose resistance to a first adequate (in terms of duration and dosage) SRI trial was documented and where outcome was clearly defined in terms of decrease in Yale-Brown Obsessive-Compulsive Scale (YBOCS) scores and/or response/ remission rates (according to the YBOCS).

RESULTS

We identified five strategies supported by positive results in placebo-controlled randomized studies: 1) antipsychotic addition to SRIs (16 RCTs, of them 10 positive; 4 head-to-head RCTs); among antipsychotics, available RCTs examined the addition of haloperidol (butyrophenone), pimozide (diphenyl-butylpiperidine), risperidone (SDA: serotonin- dopamine antagonist), paliperidone (SDA), olanzapine (MARTA: multi-acting receptor targeted antipsychotic), quetiapine (MARTA) and aripiprazole (partial dopamine agonist); 2) CBT addition to medication (2 positive RCTs); 3) switch to intravenous clomipramine (SRI) administration (2 positive RCTs); 4) switch to paroxetine (SSRI: selective serotonin reuptake inhibitor) or venlafaxine (SNRI: serotonin-norepinephrine reuptake inhibitor) when the first trial was negative (1 positive RCT); and 5) the addition of medications other than an antipsychotic to SRIs (18 RCTs performed with several different compounds, with only 4 positive studies).

CONCLUSION

Treatment-resistant OCD remains a significant challenge to psychiatrists. To date, the most effective strategy is the addition of antipsychotics (aripiprazole and risperidone) to SRIs; another effective strategy is CBT addition to medications. Other strategies, such as the switch to another first-line treatment or the switch to intravenous administration are promising but need further confirmation in double-blind studies. The addition of medications other than antipsychotics remains to be studied, as several negative studies exist and positive ones need confirmation (only 1 positive study).

Obsessive-Compulsive Disorder: Autoimmunity and Neuroinflammation

PURPOSE OF REVIEW

Here, we propose to review the immuno-inflammatory hypothesis in OCD given the concurrent incidence of autoimmune comorbidities, infectious stigma, and raised levels of inflammatory markers in a significant subset of patients. A better understanding of the immune dysfunction in OCD may allow stratifying the patients in order to design personalized pharmaco/psychotherapeutic strategies.

RECENT FINDINGS

A persistent low-grade inflammation involving both innate and adaptive immune system with coexisting autoimmune morbidities and stigma of infectious events has been prominently observed in OCD. Hence, specific treatments targeting inflammation/infection are a feasible alternative in OCD. This review highlights that OCD is associated with low-grade inflammation, neural antibodies, and neuro-inflammatory and auto-immune disorders. In some subset of OCD patients, autoimmunity is likely triggered by specific bacterial, viral, or parasitic agents with overlapping surface epitopes in CNS. Hence, subset-profiling in OCD is warranted to benefit from distinct immune-targeted treatment modalities.

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a highly prevalent and chronic condition that is associated with substantial global disability. OCD is the key example of the 'obsessive-compulsive and related disorders', a group of conditions which are now classified together in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and the International Classification of Diseases, 11th Revision, and which are often underdiagnosed and undertreated. In addition, OCD is an important example of a neuropsychiatric disorder in which rigorous research on phenomenology, psychobiology, pharmacotherapy and psychotherapy has contributed to better recognition, assessment and outcomes. Although OCD is a relatively homogenous disorder with similar symptom dimensions globally, individualized assessment of symptoms, the degree of insight, and the extent of comorbidity is needed. Several neurobiological mechanisms underlying OCD have been identified, including specific brain circuits that underpin OCD. In addition, laboratory models have demonstrated how cellular and molecular dysfunction underpins repetitive stereotyped behaviours, and the genetic architecture of OCD is increasingly understood. Effective treatments for OCD include serotonin reuptake inhibitors and cognitive-behavioural therapy, and neurosurgery for those with intractable symptoms. Integration of global mental health and translational neuroscience approaches could further advance knowledge on OCD and improve clinical outcomes.

Increased Fear Memory and Glutamatergic Modulation in Compulsive Drinker Rats Selected by Schedule-Induced Polydipsia

Compulsive behavior is observed in several neuropsychiatric disorders such as obsessive-compulsive disorder (OCD), anxiety, depression, phobia, and schizophrenia. Thus, compulsivity has been proposed as a transdiagnostic symptom with a highly variable pharmacological treatment. Recent evidence shows that glutamate pharmacotherapy may be of benefit in impaired inhibitory control. The purpose of the present study was: first, to test the comorbidity between compulsivity and other neuropsychiatric symptoms on different preclinical behavioral models; second, to assess the therapeutic potential of different glutamate modulators in a preclinical model of compulsivity. Long Evans rats were selected as either high (HD) or low (LD) drinkers corresponding with their water intake in schedule-induced polydipsia (SIP). We assessed compulsivity in LD and HD rats by marble burying test (MBT), depression by forced swimming test (FST), anxiety by elevated plus maze (EPM) and fear behavior by fear conditioning (FC) test. After that, we measured the effects of acute administration (i.p.) of glutamatergic drugs: N-Acetylcysteine (NAC; 25, 50, 100 and 200 mg/kg), memantine (3.1 and 6.2 mg/kg) and lamotrigine (15 and 30 mg/kg) on compulsive drinking on SIP. The results obtained showed a relation between high compulsive drinking on SIP and a higher number of marbles partially buried in MBT, as well as a higher percentage of freezing on the retrieval day of FC test. We did not detect any significant differences between LD and HD rats in FST, nor in EPM. The psychopharmacological study of glutamatergic drugs revealed that memantine and lamotrigine, at all doses tested, decreased compulsive water consumption in HD rats compared to LD rats on SIP. NAC did not produce any significant effect on SIP. These results indicate that the symptom clusters of different forms of compulsivity and phobia might be found in the compulsive phenotype of HD rats selected by SIP. The effects of memantine and lamotrigine in HD rats point towards a dysregulation in the glutamatergic signaling as a possible underlying mechanism in the vulnerability to compulsive behavior on SIP. Further studies on SIP, could help to elucidate the therapeutic role of glutamatergic drugs as a pharmacological strategy on compulsive spectrum disorders.

Amantadine as adjuvant therapy in the treatment of moderate to severe obsessive-compulsive disorder: A double-blind randomized trial with placebo control

AIM

The role of the glutamatergic system in the pathogenesis of obsessive-compulsive disorder (OCD) has been shown by numerous studies. The aim of the present randomized, double-blind, placebo-controlled, 12-week trial was to assess the efficacy and tolerability of amantadine as an adjuvant to fluvoxamine in the treatment of patients with moderate to severe OCD.

METHODS

One hundred patients diagnosed with moderate to severe OCD were randomized into two parallel groups to receive fluvoxamine (100 mg twice a day) plus placebo or fluvoxamine (100 mg twice a day) plus amantadine (100 mg daily) for 12 weeks. All patients received 100 mg/day fluvoxamine for 28 days followed by 200 mg/day for the rest of the trial, regardless of their treatment groups. Patients were evaluated for response to treatment using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at baseline and at Weeks 4, 10, and 12. The main outcome measure was to assess the efficacy of amantadine in improving the OCD symptoms.

RESULTS

Repeated-measure analysis of variance showed a significant effect for Time × Treatment interaction (Greenhouse-Geisser corrected: F = 3.84, d.f. = 1.50, P = 0.03) in the Y-BOCS total score and a significant effect for Time × Treatment interaction (Greenhouse-Geisser corrected: F = 5.67, d.f. = 1.48, P < 0.01) in the Y-BOCS Obsession subscale score between the two groups.

CONCLUSION

The results of this study suggest that amantadine may be effective as an augmentative agent in the treatment of moderate-to-severe OCD.

Glutamatergic augmentation strategies in obsessive-compulsive disorder

Proven treatment strategies for obsessive-compulsive disorder (OCD) include pharmacotherapy with serotonin reuptake inhibitors and cognitive behavior therapy (CBT). A significant proportion of patients (25%-30%) fail to respond to these treatment options, necessitating the need for additional treatment options to improve treatment outcomes and quality of life in patients with OCD. Augmentation strategies using various glutamatergic agents have been explored, with diverse outcomes. The aim of this review is to give an overview of the glutamatergic system in the brain with a focus on glutamatergic abnormalities in OCD and to review the existing evidence for various glutamatergic agents used for augmentation.

Current and up-and-coming pharmacotherapy for obsessive-compulsive disorder in adults

INTRODUCTION

Only 40-60% of obsessive-compulsive patients respond to first line treatments, such as selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy. Several second-line treatments have been investigated in the last two decades, and most of them seem to work, at least in a subset of patients. However, since there is still a lack of treatment predictors, the treatment of obsessive-compulsive disorder (OCD) is still empirical and non-evidence based.

AREAS COVERED

In this paper, we review current and up-and-coming pharmacotherapy for OCD in adults, focusing on two emerging fields of research, inflammation and glutamate systems, since they have attracted the greatest attention in recent years in OCD pharmacological research.

EXPERT OPINION

Most of the investigated second-line agents seem to work at least in a subset of patients with OCD. These results raise an open question: what works for who? In our opinion, this question should be answered in a precision medicine perspective or, in other words, individualizing diagnostic processes and treatment approaches. In a precision medicine approach, OCD treatment should be sub-type specific, phase specific, multimodal and sequential, and, more importantly, dimensional.

Anxiolytic properties of compounds that counteract oxidative stress, neuroinflammation, and glutamatergic dysfunction: a review

Objective:

Anxiety disorders are highly prevalent and the efficacy of the available anxiolytic drugs is less than desired. Adverse effects also compromise patient quality of life and adherence to treatment. Accumulating evidence shows that the pathophysiology of anxiety and related disorders is multifactorial, involving oxidative stress, neuroinflammation, and glutamatergic dysfunction. The aim of this review was to evaluate data from animal studies and clinical trials showing the anxiolytic effects of agents whose mechanisms of action target these multiple domains.

Methods:

The PubMed database was searched for multitarget agents that had been evaluated in animal models of anxiety, as well as randomized double-blind placebo-controlled clinical trials of anxiety and/or anxiety related disorders.

Results:

The main multitarget agents that have shown consistent anxiolytic effects in various animal models of anxiety, as well in clinical trials, are agomelatine, N-acetylcysteine (NAC), and omega-3 fatty acids. Data from clinical trials are preliminary at best, but reveal good safety profiles and tolerance to adverse effects.

Conclusion:

Agomelatine, NAC and omega-3 fatty acids show beneficial effects in clinical conditions where mainstream treatments are ineffective. These three multitarget agents are considered promising candidates for innovative, effective, and better-tolerated anxiolytics.

Oral N-acetylcysteine in the treatment of obsessive-compulsive disorder: A systematic review of the clinical evidence

Obsessive-compulsive disorder (OCD) is characterized by the presence of obsessions and/or compulsions. It is a leading cause of morbidity worldwide, as it can interfere with all aspects of life. Despite the adequate treatment trials, half of patients preserve residual or impairing symptoms and selective serotonin reuptake inhibitors (SSRIs) are not free from adverse side effects. This work aims to systematically review the current evidence available concerning the efficacy of N-acetylcysteine (NAC) in the treatment of OCD. Five randomized placebo-controlled trials (RCTs), 3 case reports and 2 case series were included. The studies developed so far are somehow contradictory. However, our pooled result from the 4 observational studies (n = 13) showed a mean reduction in Y-BOCS score after NAC treatment of -11 points (p = .01). Pooled mean difference from 4 of the 5 RCTs included was 3.35, with a95% confidence interval of -0.21-6.91 and a p-value barely below statistical significance (p = .07). This result trends to favour the use of NAC over placebo in OCD patients. NAC has an optimal tolerability profile, even in higher doses, and the most frequently reported adverse events were gastrointestinal. Despite the degree of evidence being D, in our opinion the potential of NAC is underestimated. Considering its exceptional tolerability profile, the use as an add-on agent should be contemplated, on an ad hoc basis.

Individualized Immunological Data for Precise Classification of OCD Patients

Obsessive⁻compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized treatment perspective. We found discrepancies concerning cytokines, raising the hypothesis of specific immunological etiological factors. Antibody studies support the existence of a potential autoimmune etiological factor. Infections may also provoke OCD symptoms, and therefore, could be considered as specific etiological factors with specific immunological impairments. Finally, we underline the importance of distinguishing between different etiological factors since some specific treatments already exist in the context of immunological factors for the improvement of classic treatments.

N-acetyl cysteine in the treatment of alcohol use disorder in patients with liver disease: Rationale for further research

INTRODUCTION

Alcoholic liver disease (ALD) is the leading cause of alcohol-related death and one of the most common forms of liver disease. Abstinence from alcohol is crucial to reducing morbidity and mortality associated with the disease. However, there are few pharmacotherapies for alcohol use disorder suitable for those with significant liver disease.

AREAS COVERED

This paper presents a rationale for investigating the use of N-acetyl cysteine (NAC) to promote abstinence or reduce heavy alcohol consumption for patients with an alcohol use disorder, particularly in the presence of liver disease. NAC is an antioxidant with glutamatergic modulating and anti-inflammatory properties. Evidence is emerging that oxidative stress, neuro-inflammation and dysregulation of glutamatergic neurotransmission play a key role in alcohol use disorder. Similarly, oxidative stress is known to contribute to ALD. We outline the studies that have investigated NAC to reduce alcohol consumption including preclinical and clinical studies. We also review the evidence for NAC in other addictions as well as psychiatric and physical comorbidities associated with alcohol use disorders.

EXPERT OPINION

NAC is low cost, well-tolerated and could have promise for the treatment of alcohol use disorder in the presence of liver disease. Clinical trials directly examining efficacy in this population are required.

Mapping Compulsivity in the DSM-5 Obsessive Compulsive and Related Disorders: Cognitive Domains, Neural Circuitry, and Treatment

Compulsions are repetitive, stereotyped thoughts and behaviors designed to reduce harm. Growing evidence suggests that the neurocognitive mechanisms mediating behavioral inhibition (motor inhibition, cognitive inflexibility) reversal learning and habit formation (shift from goal-directed to habitual responding) contribute toward compulsive activity in a broad range of disorders. In obsessive compulsive disorder, distributed network perturbation appears focused around the prefrontal cortex, caudate, putamen, and associated neuro-circuitry. Obsessive compulsive disorder-related attentional set-shifting deficits correlated with reduced resting state functional connectivity between the dorsal caudate and the ventrolateral prefrontal cortex on neuroimaging. In contrast, experimental provocation of obsessive compulsive disorder symptoms reduced neural activation in brain regions implicated in goal-directed behavioral control (ventromedial prefrontal cortex, caudate) with concordant increased activation in regions implicated in habit learning (presupplementary motor area, putamen). The ventromedial prefrontal cortex plays a multifaceted role, integrating affective evaluative processes, flexible behavior, and fear learning. Findings from a neuroimaging study of Pavlovian fear reversal, in which obsessive compulsive disorder patients failed to flexibly update fear responses despite normal initial fear conditioning, suggest there is an absence of ventromedial prefrontal cortex safety signaling in obsessive compulsive disorder, which potentially undermines explicit contingency knowledge and may help to explain the link between cognitive inflexibility, fear, and anxiety processing in compulsive disorders such as obsessive compulsive disorder.