Psychotic depression: a separate entity?

Many authors report that patients with psychotic and nonpsychotic major depressions differ in their response to somatic treatment. Psychotic depression is less responsive to tnicyclic antidepressants (1) and often requires a combined regimen of antipsychotics and antidepressants (2) on ECT (3). The nosological status of psychotic depression remains in question. Is psychotic depression best considered as a severe variant of major depression on as a separate entity with a characteristic pattern of demographic and symptom features, family history, course, biochemical profile, and response to treatment? There are limited and inconsistent data on this issue, but some differences between psychotic and nonpsychotic depression have been suggested. Nelson and Bowers (2) reported more psychomotor disturbance and previous episodes in psychotic depressive patients than in nonpsychotic depressive patients. In contrast Glassman and Roose (4) found more psychomotor retardation, less placebo responsiveness, and fewer previous episodes in psychotic depressive patients. Several preliminary biochemical and physiological findings seem to distinguish psychotic from nonpsychotic depressive patients. Meltzen and associates (5) reported that psychotic patients had increased serum creatinine phosphokinase and aldolase, skeletal musdc abnormalities, and lower serum dopamine 3-hydroxylase. Sweeney and associates (6) reported lower urine 3-methoxy-4-hydroxyphenethylene glycol and higher CSF homovanillic acid. These authors all used the Research Diagnostic Criteria (RDC) definition of psychotic major depressive disorder in defining their cohorts. Mendels and associates used a clinical judgment definition of psychotic depfession and found decreased CSF 5-hydnoxyindoleacetic acid (7) and decreased stage 4 and REM sleep (8). If psychotic depression is no more than a severe variant of nonpsychotic major depression, it should, aside from the presence of the psychotic symptoms, have similar clinical features. Guze and associates (9) studied 1 15 variables in 253 patients with primary and secondary affective disorder and found that delusional unipolan patients were distinguished only by more frequent psychiatric hospitalization. Most ofthe vania-