Bipolar disorder and violent crime: new evidence from population-based longitudinal studies and systematic review.

CONTEXT

Although bipolar disorder is associated with various adverse health outcomes, the relationship with violent crime is uncertain.

OBJECTIVES

To determine the risk of violent crime in bipolar disorder and to contextualize the findings with a systematic review.

DESIGN

Longitudinal investigations using general population and unaffected sibling control individuals.

SETTING

Population-based registers of hospital discharge diagnoses, sociodemographic information, and violent crime in Sweden from January 1, 1973, through December 31, 2004.

PARTICIPANTS

Individuals with 2 or more discharge diagnoses of bipolar disorder (n = 3743), general population controls (n = 37 429), and unaffected full siblings of individuals with bipolar disorder (n = 4059).

MAIN OUTCOME MEASURE

Violent crime (actions resulting in convictions for homicide, assault, robbery, arson, any sexual offense, illegal threats, or intimidation).

RESULTS

During follow-up, 314 individuals with bipolar disorder (8.4%) committed violent crime compared with 1312 general population controls (3.5%) (adjusted odds ratio, 2.3; 95% confidence interval, 2.0-2.6). The risk was mostly confined to patients with substance abuse comorbidity (adjusted odds ratio, 6.4; 95% confidence interval, 5.1-8.1). The risk increase was minimal in patients without substance abuse comorbidity (adjusted odds ratio, 1.3; 95% confidence interval, 1.0-1.5), which was further attenuated when unaffected full siblings of individuals with bipolar disorder were used as controls (1.1; 0.7-1.6). We found no differences in rates of violent crime by clinical subgroups (manic vs depressive or psychotic vs nonpsychotic). The systematic review identified 8 previous studies (n = 6383), with high heterogeneity between studies. Odds ratio for violence risk ranged from 2 to 9.

CONCLUSION

Although current guidelines for the management of individuals with bipolar disorder do not recommend routine risk assessment for violence, this assertion may need review in patients with comorbid substance abuse.