Psychosis is often a symptom of a psychiatric illness or medical problem. However, having symptoms of psychosis doesn’t necessarily mean that someone has a psychotic illness. More than 3 in 4 episodes of psychosis don’t turn out to be due to an illness.
There are a number of mental illnesses and circumstances that can cause psychosis.
- Schizophrenia: most people with schizophrenia experience a range of psychotic symptoms and commonly have difficulty organising their thoughts.
- Bipolar disorder: this is a psychological disorder where a person experiences prolonged episodes of depression or mania (mood elevation) that can lead to psychosis.
- Drug-induced psychosis: using or withdrawing from alcohol, ice and other amphetamines, LSD, marijuana, ecstasy or magic mushrooms may induce psychotic symptoms that last for short or long periods.
- Severe depression: people with severe depression can experience psychotic symptoms. This includes postnatal depression, which some women experience after giving birth.
- Brief psychotic disorder: rarely, a stressful event may prompt psychotic symptoms that last less than 1 month. There is often a quick recovery.
- Psychosis caused by illness or medicines: psychosis can be caused by chemical derangements in the body and brain from medicines, or because of illnesses affecting normal bodily functions. It can also be the result of damage to brain structures from diseases such as Alzheimer's disease.
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Last reviewed: November 2020