Psychosis

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What causes psychosis?

The cause of psychosis can be different for everyone, and research into it is happening all the time. Psychosis could be triggered by a number of things, such as:

• Physical illness or injury. You may see or hear things if you have a high fever, head injury, or lead or mercury poisoning. If you have Alzheimer's disease or Parkinson's disease you may also experience hallucinations or delusions.
• Abuse or trauma. If you have experienced abuse or a traumatic event, you are more likely to experience psychosis.
• Recreational drugs. Researchers still aren't sure whether using recreational drugs directly causes psychosis but you may be more likely to hear or see things as a result of taking certain recreational drugs, like cannabis and LSD. If you have already experienced psychosis, using recreational drugs can make the symptoms worse, in particular if you take high-potency cannabis ('skunk').
• Alcohol and smoking. Drinking alcohol and smoking may also stop medication from effectively treating your symptoms, making relapse more likely.
• Prescribed medication. You might also experience psychosis as a side effect of some prescribed drugs or while you are coming off psychiatric drugs.

"It's an illness that can be treated just like any other. I don’t choose or want to be psychotic any more than people choose or want any other types of ill health."

• Hunger. You may experience hallucinations if you are very hungry, have low blood sugar or if you are not getting enough food.
• Lack of sleep. You may experience hallucinations if you have a severe lack of sleep.
• Bereavement. If you have recently been bereaved, you may hear them talking to you. You may also feel that they are with you even though you can't see them.
• Spiritual experiences. Some people experience voices or visions as part of a spiritual experience. This may be a positive experience for you. It may make you feel special or important and help you make sense of your life. It could however also be a negative experience – for example, you may feel that you're possessed by an evil spirit.
• Genetic inheritance. You are more likely to develop psychosis if you have a parent or sibling who has experienced psychosis, but researchers aren't sure why this happens.

This information was published in January 2020. We will revise it in 2023.

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