Research Links Severe Mental Illness And Substance Use

Research Links Severe Mental Illness And Substance Use

By Sarah Peters

New data linking severe mental illness and substance use could lead to more effective and streamlined treatment options for clinicians and patients, according to a leading expert in psychiatry and addiction issues.

The Washington University School of Medicine St. Louis and the University of Southern California jointly conducted a study of nearly 20,000 individuals, 9,142 of which were diagnosed with severe psychotic illnesses, collected over a five-year period. The findings were published online earlier this month in JAMA Psychiatry.

“What we are learning is that this overlap of mental illness with addictive disorders is not random,” said the National Institute on Drug Abuse Deputy Director Wilson Compton. The organization, part of the National Institute for Heath, provided the funding for the study.

Researchers looked at the nicotine, alcohol, marijuana and recreational drug use in mentally healthy test subjects and psychiatric patients diagnosed with schizophrenia, bipolar disorder or schizoaffective disorder. The study found that 30 percent of those with a severe mental illness engaged in binge drinking (four servings of alcohol or more), compared to 8 percent in the mentally healthy population.

The results for smoking and marijuana were much higher. More than 75 percent of those with severe mental illness were heavy smokers and 50 percent were heavy marijuana users. In the mentally healthy population, only 33 percent were heavy smokers and 18 percent were heavy marijuana users. While it is not yet known why the simultaneous occurrence exists, Compton said the findings do much in the way of helping both patients and doctors.

“We can use the fact that [mental illness and addictive disorders] go together to better reorganize our treatment centers to both address the mental illness and the substance issues,” he explained.

Clinicians have long suspected the co-occurrence of mental illness and substance use and even documented comorbidity—the concurrence of two disorders in one individual—in past studies. However, Compton described these new findings as a “wake-up call.”

“This kind of work is particularly important for the psychiatric community and treating clinicians,” Compton said. “For far too long psychiatry has ignored the problems related to substances while they focused on the mental illness of their patients.”

Establishing what causes simultaneously occurring disorders or determining if one caused the other has eluded clinicians thus far for several reasons. One reason being that some drugs have side effects, such as hallucinogens, that can cause symptoms similar to that experienced in a psychotic illness, according to the NIDA website.

Further complicating the issue is that drugs are often prescribed to treat severe mental illnesses.

“Mental illnesses can lead to drug abuse,” according to the NIDA website. “Individuals with overt, mild, or even subclinical mental disorders may abuse drugs as a form of self-medication. For example, the use of tobacco products by patients with schizophrenia is believed to lessen the symptoms of the disease and improve cognition.”

Although the cause behind the link remains a mystery, the importance of documenting the existence of this link with hard data should not be underestimated.

“Putting this on the radar as such a huge problem in this population of people with severe mental illness will help us both with the clinical treatment of the comorbidity and it will also help us researchers begin to understand the overlap,” lead author for the article and Washington University researcher Sarah Hartz said.

The results from the study conclusively show with hard data that mental illness and substance use need to be studied and treated together, not as individual ailments, she said.

The study was a first of its kind due in part because of its size—finding nearly 10,000 psychiatric patients with severe psychotic illness was no small task—and secondly because an overwhelming majority of the sample group agreed to allow researchers to re-contact them for future studies.

Past studies had been completed with individuals diagnosed with milder cases of mental illnesses, but this new study confirmed that rates of substance use in those with severe mental illnesses is much higher than previously assumed, according to the article.

Researchers are now planning a second, more intensely focused study of 2,500 of the original research participants diagnosed with schizophrenia to further examine the role of genetics in comorbid illnesses.

“My patients come to me all the time and ask, ‘what can I do about it if it’s already written in my genes?’” USC researcher on the study Michelle Paton said. “I tell them, this is not about destiny; this is about risk. The better we understand what risks you have, the more appropriate treatment we can offer when you come to us.” If funding for the next study is secured, researchers will begin as early as March, Paton said.

Fully understanding the relationship between mental illness and substance use is particularly important when considering past studies on the mortality and causes of death in those afflicted by severe mental illness.

On average, persons with severe mental illness die as much as 25 years younger than the general population, Hartz said. “I think it is part of the stigma of mental illness that people in the general population think [the mentally ill] have a crazy, hard life and they die because they did something dangerous and that’s not true. [The mentally ill] die of the same things we all die of but they die much earlier due to substance use.”

Preventable medical illnesses, such as lung and cardiovascular disease or cancer attributed to cigarette smoking or heavy alcohol use, are a leading cause of premature death in those with severe mental illnesses. While anti-smoking campaigns have significantly reduced illnesses related to smoking in the general population, these efforts seemed to have missed society’s more vulnerable population, Hartz said.

Part of this is due to a misguided belief that forcing a person to quit smoking or another addictive behavior while undergoing treatment for their mental illness could further damage the person’s mental health.

“When people come in for severe mental illness, we need to also treat the substance abuse,” Hartz sad. “We can’t treat them independent from each other.”

Hartz added that the responsibility to inform patients falls back on the clinicians. “Clinicians need to have a frank discussion about how important it is to quit substance use and how quitting a substance won’t destabilize [the patient] psychiatrically,” Hartz said. “Aggressively talk to your patients. The first step and the most important step is to plant the seed.”

This dialogue between patients and doctors may be of particular importance in gender and ethnic sub-groups that typically have lower rates of substance use. “The most striking finding of this study was the evidence that societal-level protective effects do not extend to individuals with severe mental illness,” according to the published article.

Findings in the study showed that participants of Hispanic and Asian decent, who typically have lower rates of substance use in the general population compared to that of Caucasians, did not benefit from any protective effect.

The same was found true for women compared to men, where women usually have lower rates of substance use. “The protective effects of belonging to these groups did not carry over to individuals with severe psychotic disorder: the odds of substance use increased to mitigate the protective effects,” according to the article. “…This highlights the need for targeting substance use specifically among individuals with severe psychotic illness because protective influences may not carry over from the general population.”

Researchers don’t yet know why severe mental illness seems to be a great nullifier. “Could it be that a severe mental illness alienates you from your group?,” Hartz wondered. “Could it be that either the use of substances helps cause the mental illness—which then takes away the protective factor—or that developing a mental illness takes you away from your peer group, making you vulnerable?”

Whatever the answer, researchers now have a concrete start provided by the new data and a launching pad for future studies.

“The numbers speak louder than assumptions,” Paton said. “This study was to show people how important it is to justify assumptions with data. The striking thing in this study, we didn’t expect the numbers to be so powerful.”

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