Since existing depression scales were designed for assessment of depre
ssion in non-psychotic populations, such scales have items which do no
t distinguish depressed from non-depressed psychotic subjects. The aut
hors describe a new scale, the Calgary Depression Scale, which was des
igned for the assessment of depression in schizophrenia. The scale was
derived from two existing scales by factor analysis and reliability a
nalysis. It has been further tested in two new samples. In the first i
t has been shown to be reliable, congruent with a self-report scale an
d valid. In the second sample it has been shown that there is no overl
ap with negative or extrapyramidal symptoms.