A delusion assessment scale for psychotic major depression: Reliability, validity, and utility.
BACKGROUND
Although delusions are the hallmark of major depression with psychotic features, a scale to measure the intensity of beliefs across multiple delusional domains in this condition has been unavailable. The development and assessment of the Delusional Assessment Scale (DAS) are described.


METHODS
Scale items were selected initially based on previous studies of delusional ideation in schizophrenia. A three-point item to assess mood congruence was added. A 15-item scale was assessed in 92 subjects participating in the four-site collaborative study of the pharmacotherapy of major depression with psychotic features. Maximum likelihood method was used to determine scale factors. The internal consistency of these factors was determined. Comparisons between scale scores and ratings from the Brief Psychiatric Rating Scale (BPRS) (Overall and Gorham 1962) were used to assess convergent and discriminant validity.


RESULTS
The data were fit by a five-factors model (impact, conviction, disorganization, bizarreness, and extension). Inter-rater reliability of the five factors ranged from .77 for conviction and .74 for impact to .37 for disorganization. Internal consistency for each of the five factors was > or =.72. Scores on specific domains were significantly correlated with the BPRS unusual thought content item and positive symptom subscale scores.


CONCLUSIONS
The DAS is a reliable measure of 5 delusional domains.
Meyers
Barnett S
BS
Department of Psychiatry, Weill Medical College of Cornell University, New York Presbyterian Hospital-Westchester Division, West Chester, New York 10605, USA. bmeyers@med.cornell.edu
English
Judith
J
Gabriele
Michelle
M
Peasley-Miklus
Catherine
C
Heo
Moonseong
M
Flint
Alastair J
AJ
Mulsant
Benoit H
BH
Rothschild
Anthony J
AJ
D000328:Adult; D000339:Affect; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001569:Benzodiazepines / Q000627:therapeutic use; D003702:Delusions / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology*; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D000077152:Olanzapine; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use; D020280:Sertraline / Q000627:therapeutic use
D014150:Antipsychotic Agents; D001569:Benzodiazepines; D000077152:Olanzapine; D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline