The assessment of thought deficit in psychotic unipolar depression and chronic paranoid schizophrenia.

In order to evaluate thought disorder in a nonschizophrenic psychotic group, psychotic depressives were compared with chronic paranoid schizophrenics and normal control subjects on two assessments of thought pathology. The data indicate that: a) psychotic depressives show thought deficits in the same areas as chronic paranoid schizophrenics, and b) idiosyncratic thinking is the single most prominent thought disorder in both psychotic groups. Certain subtypes of thought disorder may be characteristic of psychosis in general rather than of any specific diagnostic category. A psychoticism profile would include idiosyncratic thinking, restricted abstracting ability, linguistic errors, content deficit, intermixing, and loss of goal.