Distinguishing psychotic depression from melancholia.

We contrast 25 patients with "psychotic depression" (PD) against two age- and sex-matched groups of melancholic depressed patients. In terms of clinical features, specificity of PD was suggested for several features, including delusions, morbid cognitions (involving guilt and a sense of deserving punishment), hallucinations and constipation. In addition, the PDs had significantly higher levels of behaviourally rated psychomotor disturbance. A comprehensive list of risk factors to depression (e.g., socio-demographic, family history, parental influences, medical disorders, anxiety, stressors and personality style) were examined, without clear differentiation between the comparison groups apart from the suggestion that being a "worrier" and having tenuous stability under stress was over-represented in the PDs. Findings favour the view that psychotic depression is a sub-type of melancholic depression (accounting for the similar expression of the majority of clinical and possible aetiological variables across our contrasted "types'). Findings also suggest possible benefits from future phenomenological studies of psychotic depression relying more on observer-based rather than self-report or symptom data sets. Aetiological studies would benefit from focussing on those features identified as distinguishing the condition from melancholic depression.