Demographic and clinical characteristics
A total of 29 subjects with bipolar disorder reported having been convicted for a crime. Subjects with history of conviction had less education than other subjects [12.5 ± 2.6 years (n = 29) versus 14.1 ± 2.0 years (n = 77), t = 3.4, p < 0.005, effect size (Cohen’s d) = 0.7]; but did not differ in current age [36.7 ± 8.2 (n = 29) versus 37.7 ± 11.1 (n = 86), t = 0.4, d = 0.1], age at onset of bipolar disorder [17.7 ± 9.5 (n = 25) versus 17.1 ± 8.4 (n = 83), t = 0.3, d = 0.07], gender (16 of 52 men and 13 of 59 women, Fisher Exact test (FET) p = 0.39), or ethnicity [χ2 (df = 2) = 3.5, p = 0.2]. Neither gender nor ethnicity significantly affected any results of this report, except as specifically noted.
Convictions were for nonviolent crimes: fraud, drug possession or selling (n = 13), burglary or crimes against property (n = 7); or violent crimes against persons: assault, robbery (n = 8). There were no significant differences in impulsivity-related or clinical characteristics across these categories, except as noted below.
Current clinical state included 32 interepisode subjects (not meeting criteria for depression, mania, or hypomania), 20 manic/hypomanic, 37 depressed, and 25 with combined depression and mania/hypomania. Past conviction was not related to current clinical state [χ2 (df = 3) = 2.2, p = 0.5], mania, depression, anxiety, or psychosis scores on SADS-C (ItI < 1.0, p > 0.4), or pharmacological treatments (FET p > 0.2).
Cluster B symptoms, course of illness, and self-reported history of criminal behavior
Subjects who reported criminal conviction had higher ASPD scores than those who had no criminal conviction (7.1 ± 3.9 versus 2.6 ± 1.7, Mann–Whitney, z = 3.5, p < 0.0005); borderline personality disorder scores did not differ (4.8 ± 1.7 versus 4.7 ± 2.9, z = 0.7). summarizes course of illness in subjects with or without histories of convictions. Subjects who had been convicted were more likely to have many manic and total episodes. Course was predominately manic in 8 subjects with convictions versus 9 without, predominately depressive in 5 versus 19, and without predominate episode type in one versus 19 [χ2 (df = 2) = 8.5, p = 0.015]. Subjects with convictions were more likely to have histories of a substance use disorder and of a suicide attempt. BIS-11 scores did not differ (p > 0.2).
Course of illness and history of criminal behavior
Increased history of suicide attempts in subjects with conviction histories may have been related to more episodes of illness. Further, we have shown that subjects with bipolar disorder and medically severe suicide attempts had increased IMT commission errors and faster reaction times (44
). We investigated these relationships using logit analysis, with suicide attempt history as dependent variable, total episodes, IMT commission errors, and IMT reaction time as independent variables, and history of conviction as a categorical independent variable. Independent variables were those that differed between subjects with or without conviction history and suicide attempt in univariate analyses. The only variable significantly associated with suicide attempt was total episodes of illness (Wald statistic = 7.3, p = 0.007; for all other independent variables, Wald statistic < 1.0, p > 0.4).
Laboratory-measured impulsivity and history of criminal behavior
shows that conviction history in bipolar disorder was associated with impaired response inhibition, including increased commission errors and accelerated reaction times. Reward-delay impulsivity did not differ between subjects who had been convicted and those who had not (TCIP and SKIP, |t
| < 1.0). Logit analysis was conducted with conviction history as dependent variable, and variables significantly associated with criminal conviction in univariate analyses as independent variables. Decreased education was not included because of its potentially circular relationship as both a cause and an effect of antisocial behavior and impulsivity (45
). shows that number of ASPD symptoms, increased commission errors, and accelerated reaction time, but not number of manic episodes or substance use disorder, were significantly associated with history of conviction. There was a potential interaction whereby history of conviction appeared more likely in subjects with both many manic episodes and substance use disorder than with either alone, but it did not reach significance (p = 0.076).
Immediate Memory Task performance and criminal history
Contributors to history of criminal conviction in bipolar disorder
We conducted further analyses to determine whether the variation in symptoms and affective state across subjects could have influenced apparent relationships between impulsivity measures and history of conviction. When depression, mania, anxiety, and psychosis factor scores were added to the model, significant effects of ASPD symptoms (Wald statistic 4.7), commission errors (Wald statistic 3.9), and reaction times (Wald statistic 3.8) persisted (all p < 0.05); symptom factor scores had no significant effects (Wald statistic < 1.7, p > 0.25). An analogous analysis with affective state (euthymic, depressed, manic, mixed) in the model revealed persistence of nearly identical contributions of ASPD symptoms, commission errors, and reaction times, with no effect of affective state (Wald statistic < 0.67, p > 0.6).
Relationships to history of violent crime
A total of 8 of the 29 convicted subjects had been convicted for a violent crime. They did not differ from those only convicted for nonviolent crimes with respect to numbers of ASPD or borderline symptoms. In terms of impulsivity, subjects convicted for violent crimes differed only by having lower BIS-11 motor scores than those with nonviolent crimes: 28.9 ± 5.6 in subjects not reporting conviction (n = 91), 30.6 ± 4.9 in those reporting conviction for nonviolent crimes (n = 19), and 24.7 ± 6.0 in subjects reporting conviction for violent crimes (n = 8); F(2,115) = 3.2, p = 0.04; violent versus nonviolent difference, p < 0.05, Tukey HSD; BIS-11 total, attentional, and non-planning scores did not differ across groups. Performance on human laboratory measures of impulsivity, including IMT (|t| < 1.4, p > 0.2), TCIP (|t| < 0.6, p > 0.5), and SKIP (|t| < 1.0, p > 0.3), also did not differ. History of substance use disorder did not predict conviction for violent crime, but only five subjects convicted for any type of crime did not meet criteria for a substance use disorder. Unlike criminal history in general, there was a possible relationship to gender (nonviolent: 9 men and 10 women; violent: 7 men and 1 woman, FET = 0.06). On logit analysis with BIS-11 motor score and gender as independent variables, BIS-11 motor score contributed significantly (Wald statistic = 4.3, p = 0.037), but gender did not (Wald statistic = 2.4, p = 0.13).