Gabapentin's effect on agitation in severely and persistently mentally ill patients

OBJECTIVE: To study the effects of adjunctive gabapentin on agitation in severely and persistently mentally ill (SPMI) inpatients. METHOD: Eleven chronic SPMI inpatients on stable psychotropic medication regimens were evaluated before and after the initiation of adjunctive gabapentin for six months. The following psychometric tests were used: Brief Psychiatric Rating Scale (BPRS), Corrigan Agitated Behavior Scale (CABS), and Clinical Global Impression (CGI)-Severity. Data collection was accomplished via retrospective chart review. An internal reliability check indicated that a chart review BPRS is significantly predictive of one performed face-to-face. RESULTS: Statistically significant reductions were found at six months for each assessment instrument (p < 0.05, two-tailed). BPRS scores were reduced from 40.6 to 33.2, CABS from 34.4 to 25.0, and CGI-Severity from 5.9 to 5.3. The bulk of the BPRS reduction was accounted for by several subscores exclusive of those assessing affective/anxious symptomatology. Adverse effects were minimal. Two patients were discharged 12 and 17 months after implementation of gabapentin. CONCLUSIONS: Adjunctive gabapentin appears to be associated with a reduction in agitation in chronically hospitalized SPMI patients. Controlled, prospective trials are needed before any definitive conclusion can be drawn regarding the role of gabapentin in the treatment of this group of patients.