In the largest ever assessment of substance
use among people with severe psychiatric illness, researchers at Washington
University School of Medicine in St Louis and the University of Southern
California have found that rates of smoking, drinking and drug use are
significantly higher among those who have psychotic disorders than among those
in the general population.
The study is published online in the
journal JAMA Psychiatry.
The finding is of particular concern
because individuals with severe mental illness are more likely to die younger
than people without severe psychiatric disorders.
"These patients tend to pass away much
younger, with estimates ranging from 12 to 25 years earlier than individuals in
the general population," said first author Sarah M. Hartz, MD, PhD,
assistant professor of psychiatry at Washington University.
Heart disease and cancer
die from drug overdoses or commit suicide – the kinds of things you might
suspect in severe psychiatric illness. They die from heart disease and cancer,
problems caused by chronic alcohol and tobacco use."
Read: What is severe mental illness?
The study analysed smoking, drinking and
drug use in nearly 20 000 people. That included 9 142 psychiatric patients
diagnosed with schizophrenia, bipolar disorder or schizoaffective disorder – an
illness characterized by psychotic symptoms such as hallucinations and
delusions, and mood disorders such as depression.
The investigators also assessed nicotine
use, heavy drinking, heavy marijuana use and recreational drug use in more than
10 000 healthy people without mental illness.
The researchers found that 30% of
those with severe psychiatric illness engaged in binge drinking, defined as
drinking four servings of alcohol at one time. In comparison, the rate of binge
drinking in the general population is 8%.
Among those with mental illness, more than
75% were regular smokers. This compares with 33% of those in the control
group who smoked regularly.
There were similar findings with heavy marijuana
use: 50% of people with psychotic disorders used marijuana regularly,
versus 18% in the general population. Half of those with mental illness
also used other illicit drugs, while the rate of recreational drug use in the
general population is 12%.
Read: Drinking affects the mental health of an unborn child
"I take care of a lot of patients with
severe mental illness, many of whom are sick enough that they are on
disability," said Hartz. "And it's always surprising when I encounter
a patient who doesn't smoke or hasn't used drugs or had alcohol problems."
Hartz said another striking finding from
the study is that once a person develops a psychotic illness, protective
factors such as race and gender don't have their typical influence.
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