People found not guilty by reason of insanity show a surprisingly mixed criminal risk profile

People who experience severe mental health conditions are frequently overrepresented in the criminal justice system, but their psychiatric symptoms alone do not always explain their legal troubles. A recent study found that standard criminal risk factors, such as antisocial attitudes and having friends involved in crime, are strongly linked to whether a psychiatric patient has been involved in the legal system. The research was published in Law and Human Behavior.

In the past, intervention programs aimed at reducing repeat offenses among people with mental illness focused almost entirely on treating psychiatric symptoms. These medical interventions routinely failed to keep people out of jail. Researchers began to realize that most people with mental illness do not commit crimes because of hallucinations or delusions.

Instead, their criminal behavior is closely linked to the same risk factors that drive crime in the general population. In the fields of criminology and psychology, experts often refer to the central eight criminogenic risk factors. These include a history of antisocial behavior, antisocial personality traits, antisocial friends, substance abuse, family or marital problems, school or work difficulties, a lack of positive recreational activities, and criminal attitudes.

Researchers have consistently found that these non-clinical factors outperform traditional mental health variables in predicting criminal behavior. This means that mental illness alone does not necessarily increase an individual’s risk of breaking the law. Instead, some people with mental illness happen to have co-occurring antisocial tendencies that lead to legal trouble.

While this pattern holds true for general psychiatric patients, a unique subset of individuals occupies a gray area between the mental health and legal systems. These are patients who have been found not guilty by reason of insanity. In these specific cases, a court has determined that the person is not legally responsible for a crime because a mental disease or defect impaired their actions at the time of the offense.

Because their crimes are legally attributed to mental illness, one might assume these individuals lack the general criminal risk factors seen in other offenders. To test this idea, psychology researchers Angelea Bolaños, Faith Scanlon, and their colleagues set out to compare different groups of psychiatric patients. They wanted to see how insanity acquittees stacked up against other patients in terms of criminal attitudes, social support, and psychiatric distress.

The researchers gathered data from 349 participants across three distinct groups. The first group consisted of 74 psychiatric patients who had a history of misdemeanor or felony convictions. The second group included 68 psychiatric patients who had no history of criminal involvement. Both of these groups were recruited from a short-term, private inpatient psychiatric hospital in Texas.

The third group was made up of 207 forensic patients residing in the California state hospital system. These individuals had been found not guilty by reason of insanity and were institutionalized for mandatory psychiatric treatment. To compare the groups, the research team administered a series of self-report questionnaires designed to measure attitudes toward crime, social support networks, and current mental health.

One survey assessed general criminal tendencies, conduct problems, and antisocial personality traits. Another measured the participants’ number of criminal friends and their level of agreement with antisocial attitudes, such as feelings of entitlement or the belief that violence is justified. A third questionnaire evaluated how much support the participants felt they received from family, friends, and romantic partners.

Finally, the participants completed an inventory that measured the severity of their current psychiatric symptoms over the previous week. This included looking at markers for anxiety, depression, and paranoia. The researchers then used statistical models to see if the combination of these traits could accurately distinguish the three types of patients from one another based solely on their survey answers.

The team discovered that patients with mental illness and a history of typical criminal involvement scored the highest on almost all indicators of criminal risk. This group reported having the most criminal associates and the strongest antisocial attitudes. They also reported the lowest levels of perceived positive social support from their families and friends.

The patients found not guilty by reason of insanity presented a more mixed profile. They showed some shared criminal risk factors with the traditional criminal group, scoring higher on general criminal tendencies than the patients with no legal history. However, they did not display the same elevated levels of antisocial attitudes as the group with typical legal involvement.

When it came to social networks, the insanity acquittees actually resembled the patients with no criminal history. Both of these groups reported feeling a comparable level of social support. The researchers suggest that friends and family might remain more supportive of someone whose crime is attributed to a mental health crisis, compared to someone who engages in standard criminal behavior.

In an unexpected twist regarding psychiatric symptoms, the insanity acquittees reported the lowest severity of current mental health distress among all three groups. The researchers suspect this is due to the nature of their hospitalizations. The Texas patients were in a short-term, acute crisis facility, while the California forensic patients had likely been living in a stable, long-term therapeutic environment for an extended period, allowing their symptoms to subside.

Overall, the data showed that criminal risk factors and social support metrics successfully sorted roughly two thirds to three quarters of the participants into their correct legal categories. This predictive accuracy reinforces the idea that criminal attitudes and social environments are defining features of justice-involved populations. The results highlight the need for treatment programs to target these specific criminal risk factors alongside standard psychiatric care.

For example, specialized rehabilitation programs exist to address the concurrent mental health and criminal needs of people in the justice system. Providing this kind of dual-focused therapy could assist forensic patients in developing necessary life skills to optimize their recovery. Preparing these patients for eventual release requires treating the whole person, rather than viewing them solely through a psychiatric lens.

While the study offers a detailed look at forensic and non-forensic patients, the research design relies on data collected at a single point in time. This cross-sectional approach prevents researchers from determining exactly how a person’s mental illness and criminal behavior evolved over time. It is impossible to know whether a patient’s antisocial attitudes developed before or after their psychiatric symptoms began.

The reliance on self-reported questionnaires also introduces the possibility of response bias. Participants might have underreported their antisocial attitudes or exaggerated their mental health symptoms based on what they thought the researchers wanted to hear. Corroborating these self-reports with official legal records or clinician observations in future studies could yield a more comprehensive picture of their behavior.

The sample composition limits how broadly the results can be applied to the general population. The patients from the Texas hospital lacked demographic diversity, being predominantly White and male. Comparing patients across two different states also introduces variations in how different legal systems define and handle insanity acquittals, meaning a patient in California might be treated differently than one in Texas.

A final complication is that 85 percent of the forensic patients in the California sample had additional criminal convictions on top of the charges that led to their insanity acquittals. This high rate of prior criminal behavior blurs the boundary between the strictly psychiatric and the strictly criminal groups. Future investigations could separate insanity acquittees based on their past criminal histories to better understand this unique population.

The study, “Psychiatric Symptoms and Criminogenic Risk in People With Mental Illness: Comparing Patients Across Forensic and Nonforensic Settings,” was authored by Angelea D. Bolaños, Faith Scanlon, Robert D. Morgan, Sean M. Mitchell, and Darci Delgado.