Considerable inconsistency exists in the literature concerning the clinical features of depression associated with a good response to anti-depressant medication. Abraham et al. (1963) summarized the literature to that date; the general consensus of opinion was that imipramine had its best effect in depressions of the endogenous rather than those of the neurotic type, but their study on depressed out-patients did not support this conclusion. Browne et al. (1963), working with in-patients, reported that reactive depressives showed a better response to amitriptyline than did endogenous depressives. Burt et al. (1962), in their report of the response of 73 depressed female in-patients treated with imipramine or amitriptyline, demonstrated a much better response to both drugs by reactive as compared with endogenous depressives. Spear et al. (1964) found no significant difference in respect to “endogenicity”, in the response of depressed in- and out-patients to tranylcypromine and imipramine. Richmond and Roberts (1964) reported that out-patients suffering from endogenous depression responded much better to a variety of anti-depressant drugs than did those suffering from reactive depression.