How drugs and alcohol can affect your mental health
It is common for people to experience problems with their mental health and alcohol / drug use at the same time. This is called co-occurring conditions or dual diagnosis.
Research shows that mental health problems are experienced by the majority of drug (70%) and alcohol (86%) users in community substance misuse treatment.
Death by suicide is also common, with a history of alcohol or drug use being recorded in over half (54%) of all suicides in people experiencing mental health problems.
People with substance addictions are more prone to mental health problems and people with mental health problems are more vulnerable to substance abuse. Cause and effect is complex, but the fact is that drugs and alcohol make mental health symptoms worse, make recovery from mental health problems more difficult and there is evidence that some drugs can cause mental health illness in the first place.
How can substances affect your mental health?
Below are some of the different type of substances that could have a negative impact on your mental health (this is not an exhaustive list!)
In addition, taking substances can have bad interactions with other medications or substances you might use, and these effects could be unpredictable.
For people with a mental illness, alcohol can be a problem as it is legal and very easy to get hold of. Alcohol makes some mental health issues, such as depression, feel worse and for some it could cause their mental health to relapse if they have struggled with mental health problems in the past.
Cannabis is the most commonly used drug in England. Some people take cannabis because it makes them feel relaxed and happy, but it can also make you feel anxious and paranoid.
Cannabis can cause drug-induced psychosis where you see and hear things that others may not, or believe things other people do not. This is more likely if you have used cannabis for a long time, use it frequently or use high strength cannabis.
In the short-term heroin can make you feel calm and relaxed. It relives pain and makes you feel sleepy. Heroin is highly addictive however, with larger amounts needing to be taken as you chase the feeling of that first hit.
Taking heroin can have serious long-term effects and when withdrawing from it, it may leave you feeling depressed. It can also make it difficult to sleep, which also has a negative effect on your mental health.
In the short-term cocaine can make you feel wide awake, full of energy and confidence. After this ‘high’ however, there is a low which can make you feel tired and depressed.
The highly addictive nature of cocaine means that over time and longer-term usage, the likelihood of developing longer-term mental health problems such as depression, anxiety and paranoia increase.
Prescription tranquillizers such as benzodiazepines are often prescribed by doctors to help people with anxiety. A GP will only offer a short prescription as the drug is highly addictive, but people also buy them illegally because of their relaxing effect.
Taken over a longer period of time this calming effect is replaced with feelings of confusion and mood swings.
Amphetamine and methamphetamine
In the short-term, these drugs can make you feel wide awake and alert which makes it difficult to relax and sleep. They can result in drug-induced psychosis and in the longer-term, lead to depression and anxiety.
In the short-term taking ecstasy can may you feel energetic and confident. It can, however, also have the opposite effect making you feel anxious, confused or even trigger drug-induced psychosis.
Over a longer period, ecstasy can lead to depression and in some people result in memory problems.
It is difficult to predict how you will react to a drug. You may even react differently to the same drug at different times or in different situations; whether the drug has been mixed with other substances, is interacting with other medications or substances or your mental state at the time of taking the drug.
If you have a history of poor mental health you may be more likely to experience negative mental effects from using alcohol or drugs.
Even if you previously have had no mental health problems, use of alcohol or drugs can lead to mental health problems and the negative impact on your day-to-day life that can also lead to strains on your mental health.
 Weaver et al (2003) Comorbidity of substance misuse and mental illness in community mental health and substance misuse services. The British Journal of Psychiatry Sep 2003, 183 (4) 304-313
 The National Confidential Inquiry into Suicide and Homicide by People with Mental Illness Annual Report 2016: England, Northern Ireland, Scotland and Wales October 2016. University of Manchester.