Information for the public

Psychosis and drug and/or alcohol use

Psychosis and drug and/or alcohol use

Many people with psychosis use drugs and drink in a way that is harmful (sometimes this is called having a 'dual diagnosis'). Having psychosis and using drugs and/or alcohol (sometimes called 'substance misuse') can lead to difficulties in the person's life and with their health and can complicate their treatment. The aim of this information is to explain the treatment and care people should receive when they have both psychosis and a drug and/or alcohol problem.


Psychosis is a condition that affects a person's mental state, including their thoughts, mood and behaviour. The symptoms of psychosis are:

  • hearing voices and sometimes seeing things that are not really there (called hallucinations)

  • having fixed beliefs that are false but which the person believes in completely (called delusions).

People who have psychosis are often diagnosed with schizophrenia or bipolar disorder (sometimes called 'manic depression').

Drug and alcohol use

Drinking and drug use is harmful when it has a negative effect on a person's life, including their physical and mental health, relationships, work, education and finances or leads to offending behaviour. Examples of drugs used include illegal drugs (for example, cannabis, cocaine, crack cocaine and heroin), prescribed drugs that are not taken in the way that was intended (for example, diazepam) and 'over the counter' medicines that you can buy from the chemist (such as codeine linctus).

If a person becomes used to the effects of drink and drugs they may need to use more to feel the same effect (this is called developing tolerance). Repeatedly using alcohol or drugs can result in the person becoming dependent so that it is difficult to live their life without drinking alcohol or taking drugs, and difficult to stop. Alcohol and some drugs (for example, heroin and diazepam) can create physical dependence and when the person stops taking them, or reduces their use, they will almost certainly experience withdrawal symptoms. To manage these withdrawal symptoms safely medication is prescribed to help the person stop using.

Questions you could ask your healthcare team

  • What is psychosis?

  • Is my drug and/or alcohol use a concern?

  • Why am I being offered an assessment?

  • What could have caused my mental health problem?

  • Will my psychosis and drug and/or alcohol use remain confidential?

  • Who can provide my treatment and care?

  • Will someone coordinate my care if different services are involved?

  • Are there any support organisations specifically for people with both psychosis and drug and/or alcohol use in my local area?

  • Who can I contact in a crisis?

  • Have you got any information for my family, carers or significant others?

  • Information Standard