Lamotrigine augmentation in schizophrenia and schizoaffective patients with obsessive-compulsive symptoms

Obsessive-compulsive symptoms (OCS) are clinically important phenomena in schizophrenia patients. Lamotrigine has a modulating effect on glutamatergic neurotransmission relevant to pathophysiology of both schizophrenia and OCD. Efficacy and tolerability of lamotrigine in schizophrenia and schizoaffective patients with comorbid OCS were evaluated. In an 8-week, open-label trial, lamotrigine (25 mg/day for 1 week, 50 mg for 2 weeks, 100 mg for 2 weeks, 200 mg for 3 weeks) was added to ongoing psychotropic drug regimens in schizophrenia (N = 5) and schizoaffective disorder (N = 6) patients with clinically significant OCS [Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score > 16]. The Y-BOCS score for nine completers decreased significantly from baseline to week 8 (22.9 ± 6.1 vs 17.4 ± 3.6; t = 2.33, df = 1, P = 0.033). Five patients, all with schizoaffective disorder, were responders (≥35% decrease in Y-BOCS score). No significant changes were detected in schizophrenia symptom severity. Depressive symptoms, assessed with the Calgary Depression Rating Scale, improved significantly (6.4 ± 1.5 vs 4.0 ± 2.5; t = 3.19, df = 1, P = 0.013); this change positively correlated with OCS improvement (r = 0.69, P = 0.04). Lamotrigine was safe and well tolerated. Explicit evaluation of therapeutic efficacy of adjunctive lamotrigine in schizoaffective disorder patients with comorbid OCS merits further investigation.