The sleep effects of tiagabine on the first night of treatment predict post-traumatic stress disorder response at three weeks.

INTRODUCTION We sought to test the hypothesis that improvements in sleep might mediate treatment-related improvements in daytime symptoms of post-traumatic stress disorder (PTSD). We evaluated whether changes in sleep occurring on the first night of tiagabine (a gamma-amino butyric acid (GABA) reuptake inhibitor) administration predicted subsequent PTSD response. METHODS This was an open-label three-week polysomnographic (PSG) study of nightly treatment with tiagabine dosing from 2-12 mg including 20 adults with PTSD with ≥30 min of self-reported and PSG wake time after sleep onset (WASO). RESULTS A treatment night 1 decrease in self-reported and PSG WASO and an increase in slow-wave sleep (SWS) accounted for 94% of the variance in week 3 Short PTSD Rating Interview (SPRINT) score, the primary outcome measure (p<0.001). Increased night 1 SWS also accounted for 91% of the variance in Work/School Impairment and 45% of the variance in Social Life Impairment as measured with the Sheehan Disability Scale (p<0.001). These relationships were much stronger correlates of three-week outcome than three-week sleep effects. CONCLUSIONS The initial sleep response to tiagabine may mediate or be an indicator of the subsequent PTSD response. The findings highlight the importance of sleep maintenance and SWS in the treatment of PTSD and also suggest a potential relationship between SWS and daytime function.