The aim of this study was to evaluate the efficacy and tolerability of tiagabine 
in adult patients with post-traumatic stress disorder (PTSD). This 12-week, 
multicenter, double-blind study randomized patients to receive either tiagabine 
or placebo. Tiagabine (administered in divided doses) was initiated at 4 mg/d (2 
mg BID) and individually titrated of up to 4 mg/d weekly to a maximum dose of 16 
mg/d. Assessments included the Clinician-Administered PTSD Scale, Clinical 
Global Impressions of Change, Treatment Outcome PTSD Scale, Davidson Trauma 
Scale, Connor-Davidson Resilience Scale, Sheehan Disability Scale, Massachusetts 
General Hospital Sexual Functioning Questionnaire, and Montgomery-Asberg 
Depression Rating Scale. A total of 232 patients (tiagabine, n = 116; placebo, n 
= 116) were randomized. There were no significant differences in change from 
baseline in the Clinician-Administered PTSD Scale total score at final visit for 
tiagabine compared with placebo (P = 0.85). Similarly, no significant 
differences were observed with tiagabine on the other efficacy outcome measures 
(described above) compared with placebo. Tiagabine was generally well tolerated 
and not associated with weight gain, changes in sexual function, or worsening of 
depressive symptoms. Tiagabine was not significantly different from placebo in 
the treatment of symptoms of PTSD. Additional studies are needed to assess the 
role of drugs that target the gamma-aminobutyric acid system in the treatment of 
PTSD.