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4 • PSYCHOSIS
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substance use
How common is psychosis?
• Psychosis is not uncommon — about three in one hundred Australians will experience
a psychotic episode at some point during their life. People with psychosis are much
more likely to have an alcohol, tobacco or other drug problem than people who do not
experience psychosis.
What causes psychosis?
• The causes of psychosis are not fully understood. However, it is likely that a combination
of factors lead to the development of psychosis or psychotic disorders, including:
—A family history of psychosis or psychotic disorders
—Chemical imbalances in the brain
—Life experiences (e.g., stress, traumatic events, illness)
—Alcohol or other drug use
Psychosis and substance use
• As mentioned in the section of this booklet on substance-induced psychosis, alcohol
or other drug use (or withdrawal) can trigger a psychotic episode.
• People who have experienced a substance-induced psychotic episode are at high risk
of experiencing another psychotic episode in the future if they use that drug again.
• People who have experienced psychosis tend to be particularly sensitive to the effects
of drugs and can experience negative effects even at very low levels of use.
• Sometimes people with psychotic disorders use
alcohol or other drugs to help them cope with
their symptoms of psychosis. This is often called
‘self medication’. While this may provide some
short-term relief from symptoms, alcohol and
other drug use can make a person’s existing
symptoms worse. In addition, some people find
that they develop alcohol or other drug problems
because they use greater amounts more
frequently to cope with their psychosis.
• This can lead to a cycle where psychosis
symptoms and alcohol or other drug use feed
off each other (see Figure 1).
Figure 1:
Cycle of psychosis symptoms, cravings, and
alcohol, tobacco or other drug use
Alcohol, tobacco
or other drug use
Psychosis
symptoms,
low mood
or anxiety
Craving