Differences in daytime sleepiness, lifestyle disruptions, and emotional distress were compared across nine groups taking sleep-promoting substances. Groups included individuals taking zopiclone (n = 274), amitriptyline (n = 107), lorazepam (n = 258), oxazepam (n= 141), diphenhydramine HCl (n = 99), triazolam(n = 137), long acting benzodiazepines (n = 120), temazepam (n = 176), and miscellaneous other medications (n = 286). Data were gathered by self-report, using standardized instruments in a mail-back questionnaire procedure. Respondents included the first 1,598 participants enrolled in a Canadian multicentre project, including six sites attached to academic psychiatric units. Results indicated that quality of life effects differed across groups in both daytime sleepiness and lifestyle disruptions (illness intrusiveness), but not in depressive symptoms. Daytime sleepiness was significantly higher among people taking diphenhydramine HCl as compared to temazepam, zopiclone, lorazepam, and oxazepam. Illness intrusiveness was significantly higher among patients taking amitriptyline as compared to those taking triazolam, oxazepam, long-acting benzodiazepines, and zopiclone. It may be useful to inform patients of differences in psychosocial outcomes when prescribing hypnotic medications.