The main categories of causes of psychosis are:
- Mental illness: Psychosis can be caused by a mental illness, such as schizophrenia, bipolar disorder, or severe depression.
- Genetics: People with a family history of psychotic disorders such as schizophrenia have a slightly increased chance of developing psychosis. There is no single gene that causes psychosis, but a number of different genes may increase the likelihood of developing it.
- Recreational drugs: Psychosis can be triggered by the use of drugs, including cannabis, amphetamines (including speed and ice), LSD (acid), magic mushrooms, ketamine, ecstasyand cocaine.