Abstract
While most patients with obsessive–compulsive disorder (OCD) respond to serotonin re-uptake inhibitors (SRIs), augmentation strategies are used in the refractory subgroup [1]. While a recent report refers to the efficacy of gabapentin [2], to our knowledge, there have been no reports of the usage of lamotrigine for augmentation in OCD.
Eight OCD patients diagnosed on DSM-IV, who received treatment with SRIs with inadequate response, were given lamotrigine for at least 4 weeks (mean = 47.1 days). Sertraline had been administered at a dose of at least 200 mg per day and clomipramine at at least 225 mg per day, for a mean period of 14 weeks. Lamotrigine was added up to a maximum of 100 mg/day. Outcome was measured on changes in the Yale Brown Obsessive–Compulsive Scale (YBOCS), Clinical Global Improvement (CGI) Severity and Improvement subscore.
All patients completed the study. The dose of SRIs was unchanged during study. At the end of the study, only one patient reported improvement. Of the seven patients who were rated, YBOCS scores changed as follows at the end of study period compared with baseline: obsession subscore: 14.3–10.4, compulsion subscore: 13.2–9.8, total: 24.0–18.9. The CGI-Severity scores did not show any significant change. Except for one patient who scored 2 (much improved), patients did not show any significant change on CGI-Improvement. Thus, augmentation with lamotrigine did not result in improvement in most cases of refractory OCD.
The results of this study have to be interpreted with caution in view of the following limitations: (i) it was a open trial with a small sample size; and (ii) most of the patients were refractory to conventional pharmacological therapies. The brain circuits that are likely to be involved in the manifestation of OCD behaviour use serotonin along with GABA and excitatory amino acid neurones [3]. It is likely that newer drugs which modulate presynaptic release of excitatory amino acids may play a role in OCD treatment in the near future, although the potential for lamotrigine appears limited.