Intelligence quotient level and treatment of obsessive-compulsive disorders: Meta-analyses

Obsessive-compulsive disorder (OCD) is a highly heterogeneous mental disorder that could affect mental capacity and requires different treatment methods. The purpose of this meta-analysis study was to evaluate the OCD subjects' intelligence quotient (IQ) and the effect of different treatments on OCD.

Through a systematic literature search up to December-2019, 108-studies were identified, with 8049-subjects with 6719-OCD subjects. The studies identified were 45 reporting IQs in OCD and 38 reporting comparisons between selective-serotonin reuptake-inhibitors (SSRIs) to placebo in the treatment of OCD, 9 reporting comparison between SSRIs to each other, 8 reporting comparison between cognitive-behavioral therapy (CBT) to placebo and 8 reporting comparison between CBT to SSRIs. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated comparison was made according to the study content using a continuous method with a random or fixed-effects model.

Subjects with OCD had significantly lower IQ (OR, -3.74; 95% CI, -4.83 to -2.64) than normal subjects. SSRIs (OR, -4.09; 95% CI, -4.87 to -3.30) and CBT (OR, -15.13; 95% CI, -19.27 to -10.99) had better effect than placebo in OCD treatment. No significant difference were found between different types of SSRIs (OR, -0.42; 95% CI, -1.32-0.49) or between CBT and SSRIs (OR, -1.99; 95% CI, -4.20 to 0.22) with non-significant better values favoring CBT.

The IQ of the OCD subjects was significantly lower than in normal subjects. The SSRIs and the CBT had a significant effect on treating OCD. Different SSRIs are similar in their effect on OCD. More studies are required to separate between CBT and SSRIs' insignificant differences.