Psychologists help patients with serious mental illness kick nicotine and other addictions

People with SMI use substances for many of the same reasons as others do—to enhance positive feelings (get a buzz or high) or reduce negative ones (deal with trouble sleeping, disruptive thoughts, or emotional pain). Drugs that boost dopamine can counter the numbing effects of some antipsychotic medications, while cigarettes and cannabis may have calming or energizing effects. Alcohol, nicotine, and cannabis are the most commonly used substances, partly because they are easiest to obtain.

Using substances can also provide welcome recreation and social connection for people whose lives can be difficult because they have trouble finding employment and maintaining relationships, said Kavanagh.

“For someone with a serious mental disorder, something that lifts you out of all of that is actually very attractive,” he said. “It also gives you an entrée into a group of others who are using the same substance, where you may feel welcome and connected.”

Self-medication alone cannot fully explain the much higher rates of SUD in this group—48% in 2022, compared with 17% of the general population—said clinical psychologist Kim Mueser, PhD, a professor at Boston University’s Center for Psychiatric Rehabilitation who studies SMI and SUD. A theory known as the supersensitivity hypothesis holds that people with SMI are more sensitive to the effects of alcohol, cannabis, and other substances; even moderate use can trigger SUD symptoms (Miller, P. [Ed.], Principles of addiction: Comprehensive addictive behaviors and disorders, Academic Press, 2013).

The link between mental illness and substance use is bidirectional and complex. Mental illness can lead people to use substances; substances can worsen or trigger the development of mental illness. The two conditions also share common risk factors, including stress or trauma early in life and certain genetic vulnerabilities (Common comorbidities with substance use disorders research report, National Institute on Drug Abuse, 2020).

For example, evidence suggests that cannabis use during adolescence can increase the risk of developing a psychotic disorder or trigger earlier onset in people with other risk factors, such as a family history of schizophrenia. But understanding of the link is incomplete, and research is still insufficient to determine that it is causal, said clinical psychologist Michelle West, PhD, an assistant professor of psychiatry at the University of Colorado Anschutz Medical Campus who has reviewed the scientific literature on cannabis and psychosis (Psychiatric Clinics of North America, Vol. 46, No. 4, 2023).

“There’s also a small subset of people with no known risk factors who develop psychosis after using very high potency cannabis,” she said. “Unfortunately, we’re not yet able to predict who this happens to and why.”

More research on the link between specific substances and mental illnesses is part of the solution, but psychologists are also advocating for a broader shift in the way health care approaches treatment for SMI and SUD.

In the past, SMI and substance use problems were typically treated by different providers, often leaving patients with both diagnoses in limbo. When treatments are offered in parallel, they are often not coordinated: Some people are expected to quit using substances before receiving SMI treatment; others receive no help for their substance use. For conditions such as alcohol use disorder and opioid use disorder, that lack of support can be life-threatening because patients with severe addiction require medical oversight to quit.

Existing service delivery models are part of the problem, said Lara Coughlin, PhD, an assistant professor of psychiatry at the University of Michigan and a licensed clinical psychologist focused on SUD treatment, which is why psychologists have helped lead efforts to provide integrated mental health and addiction care. But another major issue is the stigma pervading society and the health care system around both SMI and SUD, as well as provider beliefs about their lack of competence to treat addiction.

“The field is trying to address stigma and provider knowledge gaps so we can make sure we’re treating the whole person instead of passing patients to other providers with the hope of them getting better,” Coughlin said.

For that reason, gaining firsthand experience with people in recovery can be just as helpful for providers as it is for patients. Peer specialists such as Ashton can help provide a living example of what effective treatment can do.

“I model recovery for [hospital] staff so that they will see our patients as people who are not just in a static situation. They can do well, and they can find a way in the world,” Ashton said. “They’re seeing folks at their lowest point, and I try to show them that this is not a life sentence.”