ABSTRACT
BACKGROUND: Obsessive-compulsive disorder (OCD) has been associated with neurocognitive impairments. The present study examined the effect of treatment on neurocognitive performance in OCD and the relationship between neurocognitive change and symptom change. The present study also examined polymorphisms influencing brain derived neurotrophic factor (BDNF) as predictors of neurocognitive change. METHOD: Treatment-seeking participants with OCD (N = 125) were assigned to cognitive behavioural therapy (CBT) alone, CBT combined with regular physical exercise, exercise alone, or a waitlist control group. Measures of OCD symptom severity and a neuropsychological battery were completed pre- and post-treatment. Blood or saliva samples were used to genotype the BDNF Val66Met polymorphism. RESULTS: OCD symptom severity was not cross-sectionally associated with neurocognitive performance. Several neurocognitive measures improved over treatment. The BDNF Val66Met polymorphism was significantly associated with worse performance on the Stroop test but did not significantly predict change in neurocognitive performance over time. LIMITATIONS: Limitations include lack of a healthy control group. CONCLUSION: Improvement in neurocognitive performance corresponded to symptomatic improvement and was independent of the BDNF Val66Met genotype.
ABSTRACT
PURPOSE: Cognitive behavioural therapy (CBT) has been found to be an effective treatment for OCD, but there remains a significant proportion of individuals who fail to show a treatment response. Aerobic exercise has previously been associated with decreases in anxiety and depression, as well as improvements in OCD symptoms in small-scale studies. The purpose of the present research was to use a randomized control trial design to examine the effects of exercise alone and in combination with CBT, on OCD symptoms and secondary symptoms. METHOD: 125 participants were randomly assigned to one of four treatment groups: waitlist control, exercise, CBT, and CBT with exercise. OCD symptom severity was measured at four points over the course of treatment, secondary outcome measures were gathered at three points over treatment. RESULTS: CBT alone and combined with exercise was associated with significantly greater OCD symptom reduction than exercise alone or the control groups. Total exercise frequency predicted OCD symptom reduction in the groups in which exercise was measured. Group membership did not significantly predict reductions in secondary outcome measures. CONCLUSION: Exercise frequency, rather than the presence or absence of exercise, appears to predict OCD symptom reduction, as did participation in CBT.
