Psychological Medicine

Original Articles

Differences in prevalence and patterns of substance use in schizophrenia and bipolar disorder

P. A. Ringena1 c1, T. V. Lagerberga1, A. B. Birkenæsa2, J. Engna2, A. Færdena2, H. Jónsdottira2, R. Nesvåga3, S. Friisa2, S. Opjordsmoena2, F. Larsena2, I. Mellea1 and O. A. Andreassena2

a1 Institute of Psychiatry, Medical Faculty, University of Oslo, Oslo, Norway

a2 Division of Psychiatry, Ullevål University Hospital, Oslo, Norway

a3 Department of Psychiatry, Diakonhjemmet Hospital, Oslo, Norway


Background Schizophrenia and bipolar disorder have partly overlapping clinical profiles, which include an over-representation of substance-use behaviour. There are few previous studies directly comparing substance-use patterns in the two disorders. The objective of the present study was to compare the prevalence of substance use in schizophrenia and bipolar disorder, and investigate possible differences in pattern and frequency of use.

Method A total of 336 patients with schizophrenia or bipolar spectrum disorder from a catchment area-based hospital service were included in a cross-sectional study. In addition to thorough clinical assessments, patients were interviewed about drug-use history, habits and patterns of use. The prevalence and drug-use patterns were compared between groups.

Results Patients with bipolar disorder had higher rates of alcohol consumption, while schizophrenia patients more often used centrally stimulating substances, had more frequent use of non-alcoholic drugs and more often used more than one non-alcoholic drug. Single use of cannabis was more frequent in bipolar disorder.

Conclusion The present study showed diagnosis-specific patterns of substance use in severe mental disorder. This suggests a need for more disease-specific treatment strategies, and indicates that substance use may be an important factor in studies of overlapping disease mechanisms.

(Received May 29 2007)

(Revised October 09 2007)

(Accepted October 17 2007)

(Online publication December 10 2007)


c1 Address for correspondence: Dr P. A. Ringen, Department of Education and Research, Division of Psychiatry, Building 49, Ullevål University Hospital, N-0407 Oslo, Norway. (Email: