Augmentation agents to serotonin reuptake inhibitors for treatment-resistant obsessive-compulsive disorder: A network meta-analysis

Glutamate dynamics and BOLD response during OCD symptom provocation in the lateral occipital cortex: A 7 Tesla fMRI-fMRS study

Obsessive-compulsive disorder (OCD) is linked with dysfunction in frontal-striatal, fronto-limbic, and visual brain regions. Research using proton magnetic resonance spectroscopy (1H-MRS) suggests that altered neurometabolite levels, like glutamate, may contribute to this dysfunction. However, static neurometabolite levels in OCD patients have shown inconsistent results, likely due to previous studies' limited focus on neurometabolite dynamics. We employ functional MRS (fMRS) and functional magnetic resonance imaging (fMRI) to explore these dynamics and brain activation during OCD symptom provocation. We utilized a combined 7-tesla fMRI-fMRS setup to examine task-related BOLD response and glutamate changes in the lateral occipital cortex (LOC) of 30 OCD participants and 34 matched controls during an OCD-specific symptom provocation task. The study examined main effects and between-group differences in brain activation and glutamate levels during the task. A whole sample task-effects analysis on data meeting predefined quality criteria showed significant glutamate increases (n = 41 (22 OCD, 19 controls), mean change: 3.2 %, z = 3.75, p < .001) and task activation (n = 54 (26 OCD, 28 controls), p < .001) in the LOC during OCD blocks compared to neutral blocks. However, no differences in task-induced glutamate dynamics or activation between groups were found, nor a correlation between glutamate levels and task activation. We were able to measure task-induced increases in glutamate and BOLD levels, emphasizing its feasibility for OCD research. The absence of group differences highlights the need for further exploration to discern to what extent neurometabolite dynamics differ between OCD patients and controls. Once established, future studies can use pre-post intervention fMRS-fMRI to probe the effects of therapies modulating glutamate pathways in OCD.

Efficacy of pharmacological treatment in OCD comorbid with tic disorder: Systematic review and meta-analysis

Up to 30% of subjects with obsessive compulsive disorder (OCD) also have a lifetime tic disorder. Several meta-analyses of pharmaceutical or psychotherapeutic interventions for the management of OCD have been published, but none specifically on patients with OCD comorbid with tics. The literature regarding pharmacological treatments of patients with this condition is mainly focused on studies of OCD. After a search of the Cochrane, EMBASE, PubMed, PsychINFO and Science Direct databases, we performed a proportion meta-analysis of the percentage of patients whose condition improved and a paired meta-analysis of the change in the OCD score (Y-BOCS). Twelve case reports were retained for qualitative analysis and 14 articles for meta-analysis. Case reports showed better efficacy of combined antidepressant-antipsychotic treatment for OCD comorbid with tic disorder. The meta-analysis showed an improvement in 29% [18-42] of patients with antidepressants. Although there was no significant difference with placebo add-on, in antidepressant-resistant OCD patients, adding an antipsychotic to the antidepressant regimen led to an increase in the number of patients who improved (67% [45-86] vs 7% [0-35]) and seemed to show a decrease in the Y-BOCS score (-10.06 [-20.38; 0.26] vs (-3.61 [-9.08; 13.85]). Our study provides new evidence on the pharmacological treatment of OCD comorbid with tics. In some patients, the condition is improved by a first-line antidepressant. In case of non-response or insufficient efficacy of antidepressants, add-on treatment with certain antipsychotics can be implemented.

Agomelatine efficacy in treatment resistant obsessive-compulsive disorder: A randomized controlled trial

BACKGROUND

Obsessive-compulsive disorder (OCD) is a prevalent and burdensome mental health condition, often resistant to conventional treatments. Agomelatine (Valdoxan), a compound acting on serotonin and melatonin systems, has shown promise in treating those with treatment-resistant OCD based on anecdotal reports and case studies.

METHODS

A randomized, double-blind controlled trial was conducted with 60 patients diagnosed with treatment-resistant OCD. Participants were randomized into an intervention group (receiving agomelatine 50 mg/day) and a control group (receiving placebo). OCD symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) over a 12-week period.

RESULTS

There were no significant differences in age, gender, or baseline Y-BOCS scores between intervention and control groups. Agomelatine did not demonstrate a significant improvement in OCD symptoms compared to placebo. Adverse events were comparable between groups, and liver enzyme levels remained within the normal range.

CONCLUSION

This study, while not confirming superior efficacy compared to placebo, underscores the need for continued investigation into agomelatine's potential for treating specific subgroups of OCD patients, underscoring the need for more comprehensive and well-controlled trials in the future.

[Treatment-resistant obsessive-compulsive disorders]

BACKGROUND

Obsessive-compulsive disorders (OCD) are mainly treated with disorder-specific cognitive behavioral therapy using exposure and response management and/or selective serotonin reuptake inhibitors; however, a significant subgroup of patients does not sufficiently benefit from this approach.

OBJECTIVE

This article provides an overview of treatment-resistant OCD.

MATERIAL AND METHODS

In this narrative review the definition, causes, diagnostic and therapeutic approaches to treatment-resistant OCD are addressed.

RESULTS

Treatment resistance can be assumed in the absence of clinically relevant improvement under therapy, in the sense of a reduction of < 25% on the Yale-Brown obsessive-compulsive scale and a score of 4 (no change) on the clinical global impression-improvement scale. The number of unsuccessful treatment attempts required to establish treatment resistance is defined differently. Causative factors include misdiagnosis, a high severity, comorbid disorders, substance use, specific symptom constellations, organic causes, environmental factors, and aggravating factors in psychotherapy and pharmacotherapy. Suggestions for diagnostic and therapeutic approaches based on the German S3 guideline on OCD are presented.

CONCLUSION

For patients with treatment resistance to first-line therapy, useful diagnostic and therapeutic recommendations are available (psychotherapeutic, psychopharmacological and neurostimulation procedures).

The use of antipsychotics in obsessive compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic disease with a prevalence in the general population of around 2%-3%, generally accompanied by a severe impairment of functioning and quality of life. A consistent subgroup of patients may not achieve adequate symptom remission with first-line treatments (i.e., cognitive behavioral therapy, selective serotonin reuptake inhibitors [SSRIs]). The most validated option for treatment-resistant cases relies on the augmentative use of antipsychotics to SSRIs, preferably of the 'second generation'. Indeed, dopamine appears to be crucially involved in OCD neuropathology due to its implication in systems relating to goal-directed behaviour and maladaptive habits. Nevertheless, the mechanism of action of antipsychotics in OCD symptom improvement is still unclear. Risperidone, aripiprazole, and haloperidol seem to be the most useful medications, whereas 'first generation' antipsychotics may be indicated in case of comorbidity with tics and/or Tourette Syndrome. Antipsychotic augmentation may be also related to side-effects, particularly in the long term (e.g., alteration in metabolic profile, sedation, extrapyramidal symptoms). The present mini-review sought to provide the most updated evidence on augmentative antipsychotic use in treatment-resistant patients with OCD, providing a road map for clinicians in daily practice and shedding light on avenues for further research.

Successful Early Lamotrigine and Aripiprazole Augmentation of Clomipramine in Severe Obsessive-compulsive Disorder

Lamotrigine and aripiprazole have shown efficacy as augmentation agents of serotonin reuptake inhibitors for treatment-resistant obsessive-compulsive disorder (OCD). To date, the efficacy of lamotrigine/aripiprazole augmentation has not been reported in OCD treatment. Herein, we report the case of a 37-year-old male with severe OCD and comorbid depression whose symptoms markedly improved after low-dose lamotrigine/aripiprazole augmentation to clomipramine. Our report suggests that early glutamatergic/antipsychotic augmentation contributes to rapid remission of OCD symptoms.

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 strategies for serotonin reuptake inhibitor-resistant obsessive-compulsive disorder: A network meta-analysis of randomised controlled trials

OBJECTIVES

Treatment-resistant obsessive-compulsive disorder is a chronic debilitating illness. We conducted a network meta-analysis [NMA] to compare the efficacy of all interventions in SRI-resistant OCD from published Randomised controlled trials [RCT].

METHODS

We performed an NMA of RCTs in SRI resistant OCD from all modalities of treatments; pharmacological, psychological, neuromodulation, neurosurgery including deep brain stimulation. The design-by-treatment interaction inconsistency model within the frequentist framework was adopted with a change in Yale-Brown Obsessive-Compulsive Scale score as the primary outcome. We conducted sensitivity analyses excluding studies examining neurosurgical interventions, deep brain stimulation, studies in the paediatric population, and studies from a single geographical region. We also conducted analyses of interventions categorised into treatment groups.

RESULTS

55 RCTs examining 19 treatments or placebo involving 2011 participants were included in the NMA. Ondansetron [Standardised mean difference -2.01 (95% CI: -3.19, -0.83)], deep TMS [- 1.95 (-3.25, -0.65)], therapist administered Cognitive Behavioural Therapy [CBT-TA] [-1.46 (-2.93, 0.01)] and aripiprazole [-1.36 (-2.56, -0.17)] were ranked as the best four treatments on using the Surface Under the Cumulative Ranking [SUCRA] percentage values (85.4%, 83.2%, 80.3%, 67.9% respectively). While all four interventions had large effect sizes, CBT[TA] narrowly missed statistical significance in our analysis. In sensitivity analyses, deep TMS was ranked as the best treatment strategy for SRI-resistant OCD. The small number of subjects in individual studies, higher confidence interval limits, and wider prediction interval for most agents warrant a cautious interpretation.

CONCLUSIONS

Considering the principal analysis and sensitivity analyses together, deep TMS, ondansetron, CBT[TA], and aripiprazole may be considered a first-line intervention for SRI-resistant OCD in adults.

OTHER

This work was not funded. The NMA has been registered with PROSPERO, [Registration number: CRD42020173589].

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.

Antiseizure medication-induced obsessive-compulsive disorder and tic disorder: a pragmatic review

INTRODUCTION

With a lifetime prevalence of 2.3%, obsessive compulsive disorder is a chronic, disabling condition that is associated with significant social and occupational impairment. Up to 30% of individuals with obsessive-compulsive disorder have a lifetime diagnosis of tic disorders. Antiseizure medication is increasingly used for a variety of physical and psychiatric illnesses. Clarification of the relationship between these symptoms/disorders and use of antiseizure medication is critically important for diagnostic and treatment purposes.

AREAS COVERED

Studies on antiseizure-induced obsessive-compulsive disorder and tic disorders are reviewed. The literature search strategy identified 89 articles. Twenty-nine articles were included in the final results. Of these, 24 are case reports or case studies, 2 cross-sectional studies, 1 chart review, 1 population-based case-control study and 1 observational prospective study assessing lamotrigine, levetiracetam, topiramate, zonisamide, and carbamazepine.

EXPERT OPINION

This study highlighted the temporal relationship of antiseizure medication use and onset of obsessive-compulsive symptoms and tics. Monitoring for medication-induced obsessive compulsions or tics should be undertaken when prescribing antiseizure medication for treatment of mood disorders or epilepsy. Further research identifying the causal relationship between antiseizure medication and de novo onset of obsessive-compulsive symptoms, obsessive-compulsive disorder and tic disorder is required.

A Systematic Review of Treatment Outcome Predictors in Deep Brain Stimulation for Refractory Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a chronic and debilitating mental disorder. Deep brain stimulation (DBS) is a promising approach for refractory OCD patients. Research aiming at treatment outcome prediction is vital to provide optimized treatments for different patients. The primary purpose of this systematic review was to collect and synthesize studies on outcome prediction of OCD patients with DBS implantations in recent years. This systematic review (PROSPERO registration number: CRD42022335585) followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-analysis) guidelines. The search was conducted using three different databases with the following search terms related to OCD and DBS. We identified a total of 3814 articles, and 17 studies were included in our review. A specific tract confirmed by magnetic resonance imaging (MRI) was predictable for DBS outcome regardless of implant targets, but inconsistencies still exist. Current studies showed various ways of successful treatment prediction. However, considering the heterogeneous results, we hope that future studies will use larger cohorts and more precise approaches for predictors and establish more personalized ways of DBS surgeries.

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.

Aripiprazole monotherapy as transdiagnostic intervention for the treatment of mental disorders: An umbrella review according to TRANSD criteria

Aripiprazole is approved in different countries as treatment for several mental disorders, but its transdiagnostic potential has not yet been assessed according to established criteria such as the recently proposed TRANSD criteria. The present work aims to test whether aripiprazole monotherapy could be considered a transdiagnostic intervention. An umbrella review of meta-analyses of randomized controlled trials (RCTs) of aripiprazole monotherapy vs placebo was conducted for any disorder defined according to standard diagnostic criteria. Primary outcomes were levels of psychiatric disease-specific symptoms. TRANSD criteria were applied to assess transdiagnosticity, while the AMSTAR -2 tool was used to assess the quality of eligible meta-analyses. Four pairwise meta-analyses and three network meta-analyses were included, consisting of 25 RCTs of aripiprazole monotherapy vs. placebo (N=5469). Aripiprazole outperformed placebo on primary outcomes in Alzheimer's disease with behavioral disturbance (AD) (neuropsychiatric symptoms SMD 0.20, 95%CI 0.05-0.35, max 15 mg/day), autism spectrum disorder (ASD) (severity of symptoms SMD 0.39, 95%CI 0.30-0.48, max 15 mg/day), bipolar I disorder (BD) (severity of manic symptoms SMD 0.30, 95%CI 0.12-0.47, max 30 mg/day), and schizophrenia/schizoaffective disorder (response rate RR 0.84, 95%CI 0.78-0.92, max 30 mg/day). TRANSD criteria were met (pooled SMD 0.25, 95%CI 0.09-0.41) across these disorders Quality was high in all the included meta-analyses according to AMSTAR-2. According to TRANSD criteria, aripiprazole monotherapy is a (dose-specific) transdiagnostic intervention to treat psychiatric disease-specific symptoms across 5 diagnoses (AD, ASD, BD (mania), schizophrenia/schizoaffective disorder), across four DSM-5 diagnostic groups (neurocognitive disorders, neurodevelopmental disorders, bipolar and related disorders, schizophrenia spectrum and other psychotic disorders).

A prospective study of intensive in-patient treatment for obsessive-compulsive disorder

Multimodal in-patient treatment incorporating intensive cognitive-behaviour therapy (CBT) and medication management is a promising alternative for obsessive-compulsive disorder (OCD) patients who do not respond to standard out-patient treatment. We prospectively examined the short-term outcome and predictors of outcome of intensive in-patient treatment in a largely pharmacotherapy-resistant OCD sample. Fifty eight consecutive patients, admitted for treatment of OCD were evaluated at admission, at discharge and 2 months post-discharge for psychiatric diagnosis, personality disorders, obsessive beliefs, insight into obsessions and severity of obsessive-compulsive, depressive and anxiety symptoms. All patients received comprehensive treatment consisting of a combination of pharmacotherapy and intensive CBT. The mean Y-BOCS score was 29.38(±5.72) at admission, which reduced to 16.62(±7.91) at discharge and 16.75(±8.85) at follow-up. Thirty five participants (60.3%) met the prespecified criteria for response and 19 (32.8%) for remission. There was a significant reduction in Y-BOCS scores at discharge [43.67 (23.81)%] and post-discharge follow-up [2.18 (29.32)%] as compared to baseline (p<0.01). Baseline Browns Assessment of Beleifs Scale score (insight) was the only variable that statistically differentiated responders and non-responders. In-patient treatment is an effective treatment for medication resistant, severe and chronic OCD. Poor insight is a potential predictor of non-response to in-patient treatment.

Pregabalin augmentation for resistant obsessive-compulsive disorder: a double-blind placebo-controlled clinical trial

BACKGROUND AND OBJECTIVE

Glutamate dysfunction has been shown to be associated with pathophysiology of obsessive-compulsive disorder (OCD). Our objective is to survey the effects of pregabalin (a glutamate-modulating agent) as an augmenting treatment for resistant OCD.

PATIENTS AND METHODS

In this 12-week double-blind placebo-controlled clinical trial, 56 patients with resistant OCD were randomly allocated to receive either pregabalin or placebo plus their current medication (sertraline). Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used to evaluate the outcomes. Adverse effects were also registered.

RESULTS

Of the 56 patients with resistant OCD who were randomly allocated in 2 groups of pregabalin (n = 28) and placebo group (n = 28), 42 patients (22 in pregabalin group and 20 in placebo group) completed the trial. Throughout the trial, the mean score decreased from 26.13± 7.03 to 8.81 ± 3.47 in the pregabalin group (p < 0) and from 26.85 ± 4.34 to 17.63 ± 4.22 in the placebo group (p < 0). At the end of trial, 16 (57.14%) patients in the pregabalin group and 2 (7.14%) patients in the placebo group showed more than 35% decline in YBOCS (p < .01). The pregabalin group showed good tolerability and safety.

CONCLUSIONS

Our study revealed that pregabalin, as an augmenting medication, is more effective than placebo in the treatment of patients with resistant OCD.

Revisiting the Efficacy and Tolerability of Topiramate for Tic Disorders: A Meta-Analysis

Background: Tic disorders (TDs) are chronic neuropsychiatric disorders that usually begin in childhood. Currently, antipsychotic drugs, such as aripiprazole and risperidone, are frequently used to treat TD. However, adverse reactions limit their further usage. The efficacy of topiramate has been reported in recent studies. This study aimed to investigate the efficacy and tolerability of topiramate in the treatment of children with TDs. Methods: In this study, we performed a meta-analysis to assess the efficacy and tolerability of topiramate for TDs and identified the randomized controlled trials to evaluate topiramate for children with TDs from PubMed, the China National Knowledge Infrastructure database, Web of Science, and relevant reference lists. Quality assessment followed the Cochrane Handbook for Systematic Reviews of Interventions. A modified Jadad scale was used to assess the quality of included studies. Risk ratio (RR) was calculated as the effect size of efficacy and tolerability of topiramate for TDs. Results: A total of 15 studies involving 1070 participants aged 2-17 were included in the present meta-analysis, and 693 (64.71%) participants were male cases, with 14 studies evaluating the efficacy of topiramate for the treatment of TD. The results suggested that topiramate was more effective than control drugs (RR: 1.13, 95% confidence interval: [1.06-1.20], I² = 36%, Q = 20.31, p = 0.09). For the adverse events, there were 15 trials included in the meta-analysis, and the results showed that topiramate had fewer adverse events than control drugs (RR: 0.54, 95% confidence interval: [0.46-0.65], I² = 45%, Q = 25.49, p = 0.03). Conclusion: Compared with haloperidol and tiapride, topiramate appears to be a promising medication with good efficacy and tolerability for children with TDs. In future studies, large-sample, double-blind, placebo-controlled trials are needed to confirm its efficacy and tolerability compared with atypical antipsychotic agents (such as risperidone or aripiprazole).

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.