A multiclinic double-blind controlled study was performed on the effects of MAP in both inpatients and outpatients with AMT as control drug. 1. Subjects consisted of 41 male and 45 female patients suffering from various types of depression. MAP was assigned to 42 cases and AMT to 44 cases. Of these patients, 14 MAP cases and 10 AMT cases were subsequently dropped for a variety of reasons to obtain 28 MAP cases and 34 AMT cases as evaluable. 2. The global improvement ratings were compared and found not significantly different for any week between the two treatments. 3. The global improvement ratings by the characteristic features of patients did not show any significant difference in any items studied between the two treatments. 4. The symptomatic improvement ratings (on the Hamilton R.S. for assessment by the physician) indicated that AMT was more effective on "anxiety (psychic)." 5. The symptomatic improvement ratings (on the Beck self-assessment scale by the patient) indicated that MAP was more effective on "work" and AMT on "pathos", "feeling of satisfaction", "withdrawal" and "loss of libido." 6. During the treament period, 74.3 percent of the MAP group and 76.9 percent of the AMT group of patients showed some side effects of accompanying symptoms, with no significant difference recognized between the two treatments. Itemwise, however, the incidence of tremor was significantly lower (p-=0.06) in the MAP group. Moreover, the MAP group tended to be less liable to such anticholinergic side effects as dry mouth, constipation, trouble of accomodation, urinary disturbance and palpitation. 7. On the basis of the above findings, it is concluded that MAP is as effective against depression as AMT and less liable to the anticholinergic side effects. It is, therefore, a very useful antidepressant.