Stability of early-phase primary psychotic disorders with concurrent substance use and substance-induced psychosis.
BACKGROUND
The stability of the diagnostic distinction between a substance-induced psychosis and a primary psychotic disorder co-occurring with substance use is not established.


OBJECTIVE
To describe DSM-IV diagnostic changes over 1 year and determine the predictive validity of baseline indicators of the substance-induced psychosis v. primary psychosis distinction.


METHODS
We conducted a 1-year follow-up study of 319 psychiatric emergency department admissions with diagnoses of early-phase psychosis and substance use comorbidity.


RESULTS
Of those with a baseline DSM-IV diagnosis of substance-induced psychosis, 25% had a diagnosis of primary psychosis at follow-up. These patients had poorer premorbid functioning, less insight into psychosis and greater family mental illness than patients with a stable diagnosis of substance-induced psychosis. Reclassifying change cases to primary psychoses on follow-up, key baseline predictors of the primary/substance-induced distinction at 1 year also included greater family history of mental illness in the primary psychosis group.


CONCLUSIONS
Further study of substance-induced psychoses should employ neuroscientific and behavioural approaches. Study findings can guide more accurate diagnoses at first treatment.
Caton
Carol L M
CL
Department of Psychiatry, New York State Psychiatric Institute, Columbia University, 1051 Riverside Drive, New York 10032, USA. clc3@columbia.edu
Hasin
Deborah S
DS
Shrout
Patrick E
PE
Drake
Robert E
RE
Dominguez
Boanerges
B
First
Michael B
MB
Samet
Sharon
S
Schanzer
Bella
B
D000328:Adult; D017831:Diagnosis, Dual (Psychiatry); D004637:Emergency Services, Psychiatric / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011237:Predictive Value of Tests; D011605:Psychoses, Substance-Induced / Q000175:diagnosis; D011618:Psychotic Disorders / Q000175:diagnosis*; D019966:Substance-Related Disorders / Q000175:diagnosis*