Living With Schizophrenia

Schizophrenia and Street Drugs

The use of street drugs has very important implications for people suffering from schizophrenia. Over half of all those with a diagnosis of schizophrenia in the UK have a diagnosed drug or alcohol abuse problem running alongside their mental illness and a recent US study found that around 26% of people with a diagnosis of schizophrenia use street drugs.6 In addition there is considerable debate at the moment around the issue of whether street drug use in the early years can actually cause schizophrenia to develop later on.

Below we consider some of these issues and ask whether street drug use has any place in recovery from schizophrenia.

Some street drugs like amphetamine cause symptoms similar to psychosis.

Some street drugs like amphetamine cause symptoms similar to psychosis. (Image: Sinisa Botas on Shutterstock)

Street Drug Use and Psychotic Symptoms

A number of drugs used illicitly for recreational purposes do cause symptoms similar to those experienced in psychosis. For instance cocaine and methamphetamine can both cause paranoia and amphetamine and LSD can cause visual hallucinations. Cannabis can cause both auditory hallucinations (hearing voices) and paranoia. It is thought that this is caused by the primary active constituent of cannabis; a chemical called delta-9-tetrahydrocannabinol.11

Although there have been attempts made by researchers to differentiate between the psychotic symptoms caused by street drugs and the symptoms of the schizophrenia itself they have had mixed results. It is in practice very difficult to say which symptoms are caused by the illness and which by the drugs.9 However in these cases, if the drug alone is to blame, then these symptoms will usually pass off when the drug use stops

Cannabis and Schizophrenia

There is now some evidence linking schizophrenia with cannabis use.

There is now some evidence linking schizophrenia with cannabis use. (Image: Shutterstock)

At the time of writing (December 2015) this is probably one of the most hotly debated subjects in the mental health field. It is true to say that the spotlight has very much fallen on cannabis use as a cause of schizophrenia and much research work is currently being carried out. It has been suggested that cannabis use in early life (young teen age) increases the likelihood of the person going on to develop schizophrenia later. It has also been suggested that with the newer forms of stronger cannabis that have become available in recent years this risk has increased.

Whilst the proponents of legalisation of cannabis argue that cannabis has few adverse health effects when compared to alcohol or tobacco use, there is a developing weight of scientific research that suggests that there is a link between cannabis use and schizophrenia. Although it would be true to say that at this stage the evidence is not yet conclusive, the accumulating weight of evidence does currently implicate cannabis as a cause of schizophrenia.

There have now been a number of authoritative studies that have shown a link between cannabis use in adolescence and the onset of schizophrenia later, for instance the recent South London study1 by Sir Robin Murray and colleagues from the Institute of Psychiatry at Kings College, London which looked at over 400 people with schizophrenia and found that use of Skunk (a type of cannabis produced from genetically modified plants) increased the risk of developing psychotic illness threefold. This more or less confirmed the findings of previous work done in the UK and overseas and was very close to the 2.4 times increased risk reported in one of the earliest studies carried out on this subject which looked at over 45,000 soldiers in Sweden.2 It also supported the findings of a three year study of over 4,800 people carried out in the Netherlands.

However these studies do not answer all the questions. For instance, is it the case that the people most likely to resort to cannabis in adolescence are also those most prone to developing schizophrenia later? That is young people who have already started to develop the prodromal symptoms. But here again there is a weight of research evidence that suggests that cannabis use will lead to schizophrenia even in those who have not yet developed any prodromal symptoms (symptoms that can appear in the very earliest stages of the illness)3.

It is still the case though that the mechanism by which cannabis acts on the brain to produce this higher risk is still not fully understood and some researchers have suggested that rather than causing an increase in the risk in the general population the risk is limited to that group in the population who already have a genetic risk of developing the illness. That is to say that if you already have a genetic predisposition to the illness, cannabis use will act as a trigger. This has implications for people who have family members who have already been diagnosed with schizophrenia and serve as a warning to stay away from street drugs and ensure that their children do the same.10 There may be something in this since, as critics of this research are quick to point out, the epidemiology does not confirm the research work in as much as the incidence of schizophrenia in the general population has remained fairly constant over the past 50 years whilst the use of cannabis has increased during that time.

There have also been studies that have connected the amount of cannabis consumed with the likelihood of developing schizophrenia and have found that the more you use cannabis the higher the risk of developing schizophrenia4.

It is also likely that people who continue to use cannabis after the onset of schizophrenia will experience a worsened outcome, having more severe negative and depressive symptoms5 This runs counter to the belief that many people working in mental health in the UK particularly those working in third sector organisations hold that people with schizophrenia use cannabis to “self medicate”. It is unlikely that cannabis use has any beneficial effect on either the positive symptoms such as delusions and hallucinations or the negative symptoms such as social withdrawal and apathy and that young people with schizophrenia (and most of them are young) who use street drugs do so for much the same reason that sane young people do: because it makes them feel good and helps to relieve the enormous feeling of despair and hopelessness that is so often a feature of this cruel illness.

Other Effects of Street Drugs

There is also the link between street drug use and dangerous behaviour in schizophrenia which has now been well established. Between 10 and 23% of people with a diagnosis of schizophrenia will exhibit violent behaviour at some point during their illness7 and around 10% of people with schizophrenia will die by suicide. The research evidence and the experience of mental health workers tell us that there are three clear predictors to dangerous behaviour in schizophrenia.8 These are: a previous history of dangerous behaviour, failing to take anti-psychotic medication and concurrent drug or alcohol abuse issues. So use of street drugs must be a major influence on the likelihood of dangerousness.

Using street drugs will seriously affect your finances and lead to long term debt problems.

Using street drugs will seriously affect your finances and lead to long term debt problems.
(Image: Billion Photos on Shutterstock)

There are other adverse effects. One thing that is certain about street drug use is that it impacts adversely on people’s finances and the more frequent the use the greater the impact. This can be very serious for people with schizophrenia who may not be very skilled at managing their financial affairs prudently or may already have debt problems (around 36% of people with mental health issues also have severe or crisis debts according to a recent study carried out by the Money Saving Expert website).

Use of street drugs will also impact adversely on the person’s reputation. It is true that an episode of schizophrenia in itself will do considerable harm to a person’s reputation given the climate of myth and misunderstanding around the illness in our society today however if we add drug abuse to that we can see that much more damage will be done. There is really no point in increasing the amount of stigma that we, as people living with schizophrenia have to face simply to achieve a short term relief from our problems.

Using street drugs will also serve to distract the person with schizophrenia from their everyday problems and reduce their motivation to overcome and deal with them. Problems with housing, benefits debt, etc affect most people with schizophrenia at some time in their recovery and need a clear head and strong motivation to cope with them. If the first reaction to these problems is to seek short term relief by taking street drugs then the problems will endure and probably get worse over time.

So it can be seen that whichever side you take in the debate around whether cannabis causes schizophrenia, street drug use after you have been diagnosed with schizophrenia has many adverse effects and so the only satisfactory way forward is to abstain from street drug use altogether.

Beating a Drug Habit

If you are using street drugs you should discuss it with your family doctor as soon as possible.

If you are using street drugs you should discuss it with your family doctor as soon as possible. (Image: Alexander Raths on Shutterstock)

If you do have a problem with use of street drugs then it is important that you get help and the sooner you act the better. The first step is to tell your GP or psychiatrist and ask them to refer you to services locally which can help you give up. It is important to appreciate that your chances of a successful recovery are made immeasurably better by getting your drug problem dealt with and that beneficial aspects of recovery such as finding and holding down a job will be next to impossible if you are still drug addicted. Many employers now ask their employees to undergo random drug testing with a zero-tolerance approach to street drug use. There are very few employers who will tolerate illicit drug use in their staff: If you use drugs and are found out you will most likely lose your job.

The NHS Choices website has advice for people who want to beat their addiction and further information about the effects of street drugs is available on the government’s Frank website. Also on NHS Choices is a handy listing of drug and alcohol services available in your area that you can access by keying in your postcode.

Using street drugs will greatly complicate an already overly complicated life with schizophrenia.

Using street drugs will greatly complicate an already overly complicated life with schizophrenia.
(Image: SanchaiRat on Shutterstock)

You may also like to try Narcotics Anonymous (known as NA), a not-for-profit organisation of recovering drug addicts that helps people beat their addiction through regular meetings and a recovery programme. Whilst many have found NA to be beneficial it should be noted that there will be some variability between meetings in different areas. In addition some people have found NA’s approach to be a little confrontational and some groups hold the line that abstinence from all drugs including antipsychotics is a good thing. Such an approach is unsuitable for people with schizophrenia.

Family and Friends

Support from family and friends is vital in schizophrenia but where drug abuse is present the first requirement is to ensure that the person with schizophrenia receives clear and unambiguous messages about the dangers that drug abuse presents and that in general street drug use is not compatible with a successful recovery.


1. Marta Di Forti, Arianna Marconi, Elena Carra, Sara Fraietta, Antonella Trotta, Matteo Bonomo, Francesca Bianconi, Poonam Gardner-Sood, Jennifer O’Connor, Manuela Russo, Simona A Stilo, Tiago Reis Marques, Valeria Mondelli, Paola Dazzan, Carmine Pariante, Anthony S David, Fiona Gaughran, Zerrin Atakan, Conrad Iyegbe, John Powell, Craig Morgan, Michael Lynskey, Robin M Murray, 2015, Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study, Published in the Lancet

2. Zammit S, Allebeck P, Andreasson S. 2002, Self reported cannabis use as a risk factor for schizophrenia in Swedish conscripts, Published in the BMJ.

3. Machielsen M, Sluis SVD, Haan LD.. 2010, Cannabis use in patients with first psychotic episode and subjects at ultra high risk of psychosis: impact on psychotic and pre-psychotic symptoms. Published in Australia and New Zealand Journal of Psychiatry.

4. Hall W and Degendhardt L, 2008, Cannabis use and the risk of developing a psychotic disorder, published in World Psychiatry.

5. Van Dijk, D Koeter M, Himan R et al, 2012, Effect of Cannabis Use on the Course of Schizophrenia in Male Patients. A Prospective Cohort Study, published in Schizophrenia Research.

6. Torrey E, 2013, Surviving Schizophrenia, Harper Perennial, P239.

7. Fazel S, Reinharth J, Serper M, Singh J, 2011, Structured Assessment of Violence Risk in Schizophrenia and Other Psychiatric Disorders: A Systematic Review of the Validity, Reliability, and Item Content of 10 Available Instruments, Published in Schizophrenia Bulletin September 2011.

8. Torrey E, 2013, Surviving Schizophrenia, Harper Perennial, P271

9. Tsuang M, Faraone S, Glatt S, 2012, Schizophrenia: the Facts, Oxford University Press p21.

10. Fleming N, Mental Health Warning for Cannabis Users, reported in The Telegraph, 2/12/2004.

11. Cortes-Briones J, Cahill J, Skosnik P, Mathalon D, Williams A, Sewell R, Roach B, Ford J, Ranganathan M, D’Souza D. 2015, The psychosis-like effects of delta-9-Tetrahydrocannabinol are associated with increased cortical noise in healthy humans, published in Biological Psychiatry December 2015.

Copyright © December 2015 LWS (UK) CIC.

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