Daily Oral Memantine Attenuated the Severity of Borderline Personality Disorder Symptoms: A Double-Blind Placebo-Controlled, Randomized Clinical Trial

Background: Borderline personality disorder (BPD) has been considered a psychiatric disorder, the effective pharmacological treatments for which have not been well established. Objectives: This study aimed to assess the efficacy of memantine (10 mg/day) in reducing BPD severity and cognitive impairment. Methods: The BPD patients diagnosed by psychologists were included and divided into the placebo (n = 19) and memantine (n = 20) groups. Included participants were randomized, double-blinded, and stabilized on the medication and psychotherapy for at least four weeks. The patients in the memantine group received oral memantine (10 mg/day) for four weeks. The severity of BPD was assessed by a self-reported questionnaire named Borderline Evaluation of Severity Over Time (BEST). Moreover, the Wisconsin test was carried out to assess executive function. Results: The mean score of the BEST test significantly decreased in week eight post-treatment in the memantine group. In addition, a significant decrease in this score was indicated in the memantine group compared to the placebo group in week eight. The mean total score of the BEST test was not significantly different before and after the placebo administration. There was no significant difference in the Wisconsin subscales, including the number of wrong answers and categories achieved after memantine or placebo administration. Perseverative errors rose after the administration of memantine. Adverse side effects did not occur in any of the participants. Conclusions: Our findings suggested the potential therapeutic effects of memantine for BPD. Furthermore, we found that a low dose of meantime might be preferable to prevent the side effects.