Lamotrigine Augmentation versus Placebo in Serotonin ‎Reuptake Inhibitors-‎Resistant Obsessive-Compulsive Disorder: ‎A Randomized Controlled Trial

Serotonin reuptake inhibitors are frequently used in first-line treatments for patients ýwith obsessive-compulsive disorder. Nevertheless, many of these patients do not ýrespond well to initial therapy. The hypothesis of glutamatergic dysfunction in specific ýbrain regions has been proposed in the pathophysiology of obsessive-compulsive ýdisorder. This study was designed to evaluate the possible efficacy of lamotrigine, a ýglutamatergic agent in Serotonin reuptake inhibitors-resistant patients with obsessive-ýcompulsive disorder.ý
This study was a 12-week, double blind, randomized, placebo-controlled trial of ýadjunctive fixed-doses of lamotrigine (100 mg) to Serotonin reuptake inhibitors therapy ýin obsessive-compulsive disorder. Eligible subjects who had a total Y-BOCS of 21 or ýabove were randomly assigned to receive adjunctive treatment with either lamotrigine ýý(n = 26), or placebo (n = 27). Response to lamotrigine was defined as clinical ýimprovement (>25% decrease in the total Y-BOCS score), which was administered at ýweeks 0, 8 and 12.ý
At the endpoint (week 12), significant differences were observed in obsession, ýcompulsion, and total Y-BOCS scores comparing lamotrigine to placebo (P = 0.01, ýý0.005 and 0.007 respectively). The mean reduction in obsession, compulsion and total ýscores in lamotrigine group was about 4.15, 4.50 and 8.73, respectively. Similarly, the ýmean reductions in the placebo group were 2.52, 2.56 and 5.07. Effect sizes for efficacy ýmeasures were calculated by Cohen’s d, and it was calculated as 0.54 for the total ýYBOCS.ý
Our findings provide evidence that this augmentation is well tolerated and may be an ýeffective strategy for patients with refractory obsessive-compulsive disorder.ýý