Adinazolam, a triazolobenzodiazepine that has an action similar to antidepressants in several pharmacological tests, was compared with amitriptyline and diazepam in endogenous depressive inpatients exhibiting dexamethasone suppression test non-suppression and/or abnormal contingent negative variation. Three parallel groups of 22 patients received in double-blind conditions either adinazolam (60-90 mg/day), amitriptyline (150-225 mg/day), or diazepam (30-45 mg/day) over a 4-week period, with weekly assessments by the Hamilton Rating Scale for Depression. Results showed significant superiority of amitriptyline over diazepam on total Hamilton depression scores. On the endogenomorphy subscale, amitriptyline induced significantly better improvement than both diazepam and adinazolam, whereas both amitriptyline and adinazolam exhibited significantly better antidepressant efficacy on the core symptoms of depression. Moreover, the dropout rate for inefficacy after 2 weeks of treatment was higher in the diazepam group. Taken together, these findings suggest that adinazolam has an antidepressant efficacy intermediate between amitriptyline and diazepam. Adinazolam was, however, much better tolerated than amitriptyline, and produced significantly fewer anticholinergic side effects.