This section explains how using drugs and alcohol can affect your mental health.

People use drugs and drink alcohol for lots of different reasons. Whatever your reason, using drugs or alcohol may have a long-term negative effect on you. The possible long-term effects include the following.

  • Needing to take more to get the same effect
  • Feeling like you must use the drug or alcohol (‘dependence’)
  • Withdrawal symptoms including feeling sick, cold, sweaty or shaky when you don’t take them
  • Having sudden mood changes
  • Having a negative outlook on life
  • Loss of motivation
  • Doing less well at work, school, college or university
  • Problems with relationships
  • Borrowing or stealing money from friends and family
  • Being secretive
  • Having episodes of drug-induced psychosis

It may take longer for your mental health to get better if you use drugs or alcohol. Drugs can make you more unwell and more likely to try and harm yourself or take your own life.

There is also some evidence that using some drugs may cause mental illness in the first place. For example, research has shown that cannabis can increase your chances of developing schizophrenia.

What does psychosis mean?

If you have psychosis, you might see or hear things, or believe things that other people do not. Some people describe it as a “break from reality”. You may also hear terms such as “psychotic symptoms”, “psychotic episode” or “psychotic experience” describing the same thing. It can be a symptom of mental illness and can also be a short-term effect of some drugs.

Drugs and effects

In this section we have listed some of the different types of substances that could have an impact on your mental health. Please be aware that this list is not exhaustive.

Taking any substances can be dangerous. They can also have bad interactions with any medications or other substances you might use.

For more information on different substances you can visit the website of ‘Talk to Frank’. They are a specialist charity that provides information on drugs. You can find their website here.


Cannabis is one of the most commonly used drugs in England. According to one study, about 6.5 per cent of people aged 16-59 measured had used it in the last year. This was around 2.1 million people. Among 16-24 year olds in the study, around 15.8 per cent had used it in the last year.

Some people take cannabis because it makes them feel relaxed or happy, but it can also make you feel anxious or feel paranoid. Some people may experience things that aren’t real. This is a sign of drug-induced psychosis. Some studies have shown that the risk of psychosis may be higher if you:

  • use cannabis for a long time,
  • use it frequently, or
  • use ‘high-strength’ cannabis, like skunk.

If you have been using cannabis and you feel that it is affecting your health, make an appointment to see your GP as soon as you can. Your doctor should not judge you, and should not tell other people you use drugs.


Some people with a mental illness have a difficult relationship with alcohol. Alcohol is legal, which means it is easier to get. It can make the feelings of some mental health issues feel worse, and for some people it could cause their mental health to relapse if they have struggled in the past.

The long-term effects of alcohol also depend on how much you drink, and how regularly you drink it. If you drink too much on a regular basis then you could cause yourself serious physical and mental harm. Drinking may also make it more difficult for you to recover from your mental illness, and may reduce your quality of life.


In the short-term, cocaine can make you feel awake, talkative and confident. After this wears off, you can feel tired and depressed. If you take a high dose there is a risk to your life. 

In the long-term, cocaine use can affect how you feel. It can affect your relationships with friends and family. Cocaine is also addictive and over time you are more likely to have ongoing problems with depression, paranoia or anxiety.


In the short-term, ecstasy may make you feel energetic, chatty and confident. It can also sometimes make you feel anxious, confused or trigger drug-induced psychosis.

In the long-term, ecstasy may make you feel depressed and anxious, and some people struggle with memory problems.


In the short-term, heroin can make you feel relaxed and calm. It takes away pain and can make you feel sleepy. But there is a higher risk that you could overdose with heroin than some other drugs.

Heroin can be taken in lots of different ways, including by injection. However, there is a high risk of getting an infection if you inject heroin, particularly if you share needles with someone else.

Heroin is very addictive and can have serious long-term effects. When you stop taking it you may feel depressed and find it hard to sleep. You may feel that heroin becomes more important than other things in your life. This might make it harder to keep a job and affect your relationships.


In the short-term, LSD may make you experience things that aren’t real. Sometimes the experience will be enjoyable, and sometimes it will be frightening (a ‘bad trip’).

There is mixed evidence about the long-term effects of LSD. We don’t know exactly how likely it is to cause mental health problems.