Memantine Treatment for Obsessive-compulsive Disorder and Generalized Anxiety Disorder

Several case reports and an open-label trial have reported efficacy of anti-glutamatergic medications for the treatment of OCD. In an open-label trial of riluzole, a glutamate release inhibitor, seven of 13 adult patients with OCD improved, and five were categorized as treatment responders. Another open trial found riluzole to be effective for four of six children with treatment-refractory OCD. N-acetylcysteine, an agent that likely attenuates glutamate neurotransmission, was effective as an augmentation in one patient with OCD. Two case reports described memantine treatment of OCD. Poyurovsky et al. reported improvement with memantine augmentation in one patient with treatment resistant OCD, while Pasquini and Biondi noted improvement in one OCD patient with checking compulsions but not in one with contamination obsessions. There have been no controlled or open-label trials of memantine in OCD reported thus far. Few studies have examined the efficacy of anti-glutamatergic agents in GAD. In an open-label trial of riluzole treatment in 18 patients with GAD, twelve patients responded and eight achieved remission. A double-blind, controlled study found that LY354740, a metabotropic glutamate receptor 2/3 (mGlu2/3) agonist, was significantly more effective than placebo for GAD. No studies of memantine in GAD have been reported thus far. We hypothesized that treatment with memantine would result in significant symptom reduction in both OCD and GAD.