Results from the double-blind, placebo-controlled trial showed that 61% of participants who received memantine were “much or very much improved,” versus 8% in the placebo group.
Dr. Jon E. Grant
“Memantine was far more effective than placebo,” lead investigator Jon Grant, MD, MPH, professor of psychiatry and behavioral neuroscience at the University of Chicago, said in an interview. “However, while subjects responded favorably, that didn’t necessarily mean there were no symptoms.”
The study was published online in the American Journal of Psychiatry.
Underrecognized, disabling
The investigators noted that trichotillomania and skin-picking disorder are underrecognized and are often disabling conditions. However, the researchers pointed out that with prevalence rates of 1.7% for trichotillomania and 2.1% for skin-picking disorder, they are not uncommon.
Behavioral therapy that attempts to reverse these habits is considered first-line treatment, but trained therapists are difficult to find. In addition, the investigators wrote that currently, there are no Food and Drug Administration–approved medications for either disorder, and pharmacologic clinical trials are relatively uncommon.
The existing data from double-blind, placebo-controlled studies support the use of the antipsychotic olanzapine, the tricyclic antidepressant clomipramine, and the supplement N-acetyl-L-cysteine (NAC). Dr. Grant also noted that previous drug trials involving patients with trichotillomania have been very short in duration.
Prior research has implicated the glutamate system in repetitive motor habits and the urges that drive them. Memantine, a glutamate receptor antagonist, targets excessive glutamatergic drive. To investigate whether this medication may be beneficial for patients with trichotillomania and skin-picking disorders, the investigators conducted a randomized placebo-controlled trial.
The study included 100 adults (86 women; mean age, 31.4) with trichotillomania, skin-picking disorder, or both; participants received memantine (n = 55) or placebo (n = 45) for 8 weeks; they received memantine 10 mg or placebo for the first 2 weeks, then 20 mg for the next 6 weeks.
The researchers, who were blinded to assignment, assessed participants every 2 weeks using the National Institute of Mental Health Trichotillomania Symptom Severity Scale, which was modified to include questions for skin-picking disorder.
The team also tracked symptoms and behaviors using additional scales, including the Sheehan Disability Scale and the Clinical Global Impressions severity scale.
At the study’s conclusion, 79 patients remained. Of those, 26 of the 43 participants in the memantine group were “very much” or “much” improved (61%), versus 3 of 36 (8%) in the placebo group. (P < .0001)
Six participants in the memantine group experienced complete remission of symptoms, compared with one in the placebo group. There were no differences between the study groups in terms of adverse events.
Study limitations included the relatively short length of the trial for what should be considered a chronic disease, as well as the inclusion of only mildly to moderately symptomatic participants.
Dr. Grant said that he would like to study how memantine works in combination with behavioral therapy.