This double-blind, placebo-controlled study investigated rebound anxiety during and after 5 weeks of nightly use of triazolam 0.5 mg, a short half-life, rapidly absorbed benzodiazepine hypnotic. The study subjects were chronic insomniacs with moderate levels of psychopathology and prior use of hypnotics. Anxiety was assessed with the Profile of Mood States (POMS), instead of the anxiety scales more typically used in psychopharmacology: the Hamilton Rating Scale for Anxiety and a visual analogue scale. The POMS test was administered twice a day during the study. The results indicated that triazolam was not associated with increased anxiety the morning or the evening after previous-night drug administration. The results are discussed in view of the methodological issues in assessing anxiety in prior studies.