Fourth Edition, September 2011

How common is psychosis?
There are many medical causes of psychosis. About 3-5% of the population 
will experience some form of psychosis in their lifetime (World Health 
Organization). A small proportion of people experiencing psychosis will 
go on to have longer-term problems with psychosis and may acquire a 
diagnosis of schizophrenia. According to Health Canada, about 0.1% 
of children and youth have schizophrenia. In the general popu-
lation, it is generally accepted that 1% has the diagnosis of 
schizophrenia.

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Making a Diff erence: An Educators’ Guide to Child and Youth Mental Health Problems
www.cymhin.ca
J 2
Psychosis
How long do they last?
Without treatment, psychotic disorders can last a lifetime. Even with eff ective treatment, psychotic disor-
ders can have lifelong impact.
What causes psychotic disorders?
Psychotic disorders result from abnormalities in the brain, particularly at the level of the chemical mes-
senger systems, such as dopamine and serotonin. The exact cause of psychotic disorders is not known. 
A family history of psychosis increases the risk that a young person will experience a psychotic disorder.
The young person may not understand what is happening to them, and symptoms can be very disturbing 
and distressing. It is easy to mistake signs of psychosis as just normal challenges that many young people 
go through. Psychosis is a serious illness, however, and early intervention is needed. With treatment and 
support, most young people will recover from psychosis.
Early warning signs of psychosis

Emotional signs, such as irritability, suspiciousness, or paranoia, anxiety, depression

Loss of motivation, diffi
culty concentrating, mood swings

Noticeable change in activity level; school performance deteriorates

Severe problems making and keeping friends

Vivid and bizarre thoughts and ideas

Perceptual changes – the feeling that things around them have changed or are somehow 
diff erent; their thoughts are sped up or slowed down.