Various psychotherapies are available for individuals with obsessive–compulsive disorder (OCD). However, the comparative effectiveness and acceptability of these therapies remain unclear.

To examine the comparative effectiveness and acceptability of different psychotherapies for OCD.

A living database of psychological interventions for OCD was utilised, and randomised controlled trials comparing psychotherapies with each other/control groups were included. Pairwise and network meta-analyses were conducted using a random-effects model. Comparative standardised mean differences (SMDs) were pooled for effectiveness in reducing OCD symptom severity post-treatment. Relative risks were calculated for acceptability. Sensitivity analyses were conducted by repeating the main analyses while controlling for specific variables to test the robustness of the findings.

A total of 68 controlled trials (76 comparisons, 4019 patients) were included, involving 7 psychotherapeutic approaches. All psychotherapies were significantly more effective than both waitlist (SMD −1.40 to −0.96) and pill placebo (SMD −1.44 to −1.00). Except for mindfulness-based therapy, all approaches were more effective than both care-as-usual (SMD −0.98 to −0.67) and psychological placebo (SMD −0.95 to −0.63). Sensitivity analyses excluding outliers, studies with comorbidities, comparisons with waitlist controls and comparisons supported by only a single study, as well as analyses restricted to adults with OCD, yielded results consistent with the main analyses. When restricted to studies rated as low risk of bias, all therapies except mindfulness-based therapy and the inference-based approach remained significantly more effective than waitlist. No significant differences were found among psychotherapies regarding effectiveness and acceptability.

Psychotherapies are similarly effective and acceptable for treating OCD. However, these findings should be interpreted with caution due to limited statistical power, substantial heterogeneity and a high risk of bias across many included studies. More methodologically rigorous research is needed to validate and strengthen the current evidence base.

While various delivery formats of cognitive–behavioural therapy (CBT) for obsessive–compulsive disorder (OCD) are available, comprehensive evidence on their comparative effectiveness and acceptability is lacking.

To examine the comparative effectiveness and acceptability of different CBT delivery formats for OCD.

An existing database of psychological interventions for OCD was utilised, with randomised controlled trials (RCTs) comparing CBT delivery formats with each other/control groups were included. Pairwise and network meta-analyses were conducted using a random-effects model. Comparative standard mean differences (SMDs) were calculated for effectiveness in reducing OCD symptom severity post-treatment. Relative risks were calculated for acceptability (conceptualised as any cause discontinuation in the acute treatment phase).

A total of 61 RCTs involving 3710 patients with OCD were included. All CBT treatment formats were significantly more effective than control groups (SMDs: −0.39 to −1.66). No significant differences were found among individual, remote-delivery, guided self-help, time-intensive and family-involved formats. However, individual, remote-delivery and family-involved formats were more effective than group (SMDs, −0.38 to −0.60), and most treatment formats were more effective than unguided self-help (SMDs, −0.58 to −0.80). Regarding acceptability, most CBT formats showed no significant differences among themselves, although they were generally more acceptable (relative risks: 1.11–1.18) than unguided self-help.

Most CBT delivery formats serve as potential alternatives to conventional individual CBT. Unguided self-help has lower but still moderate effects in reducing OCD symptom severity, and it holds important potential for assisting a larger number of individuals with OCD who face barriers to accessing treatments.

Non-suicidal self-injury (NSSI) is associated with mental disorders, yet work regarding the direction of this association is inconsistent. We examined the prevalence, comorbidity, time–order associations with mental disorders, and sex differences in sporadic and repetitive NSSI among emerging adults.

We used survey data from n = 72,288 first-year college students as part of the World Mental Health-International College Student Survey Initiative (WMH-ICS) to explore time–order associations between onset of NSSI and mental disorders, based on retrospective age-of-onset reports using discrete-time survival models. We distinguished between sporadic (1–5 lifetime episodes) and repetitive (≥6 lifetime episodes) NSSI in relation to DSM-5 mood, anxiety, and externalizing disorders.

We estimated a lifetime NSSI rate of 24.5%, with approximately half reporting sporadic NSSI and half repetitive NSSI. The time–order associations between onset of NSSI and mental disorders were bidirectional, but mental disorders were stronger predictors of the onset of NSSI (median RR = 1.94) than vice versa (median RR = 1.58). These associations were stronger among individuals engaging in repetitive rather than sporadic NSSI. While associations between NSSI and mental disorders generally did not differ by sex, repetitive NSSI was a stronger predictor for the onset of subsequent substance use disorders among females compared to males. Most mental disorders marginally increased the risk for persistent repetitive NSSI (median RR = 1.23).

Our findings offer unique insights into the temporal order between NSSI and mental disorders. Further work exploring the mechanism underlying these associations will pave the way for early identification and intervention of both NSSI and mental disorders.

Although numerous studies have examined the effects of psychological treatments for obsessive-compulsive disorder (OCD), their overall effectiveness remains unclear. We aimed to estimate their overall effect by combining all available randomized controlled trials (RCTs) comparing psychological treatments to control groups for OCD.

We conducted a meta-analysis of 48 RCTs with 55 comparisons published between 1992 and 1 January 2023. The primary outcome was OCD symptom severity, with Hedges' g calculated at post-treatment and follow-up. Random-effects models were employed for all analyses, and the risk of bias was assessed.

In general, psychological treatments demonstrated a significantly large effect (g = −1.14; 95% CI [−1.31 to −0.97]; I2 = 72.23%) on reducing OCD symptom severity post-treatment, this finding remained consistent across measures and after excluding outliers, but lost significance in the sensitivity analysis for only studies with low risk of bias. Type of treatment, control group and treatment format were associated with treatment effects. Moreover, more severe baseline OCD symptom severity predicted higher degree of treatment efficacy. No significant differences were observed in dropout rates between the treatment and control groups. Treatment effects lost significance at 3–6 and 6–12 month follow-ups. 87% of RCTs were rated at high risk of bias.

Psychological treatments are effective in reducing OCD symptom severity. However, caution should be exercised when interpreting these results due to the high heterogeneity and risk of bias across RCTs. Future studies with more rigorous methodology are required, as well as studies examining their long-term effectiveness.