DRUGS AND PSYCHOSIS with Dr. Dawn Barker

Dr. Dawn Barker

Dr. Dawn Barker

Dr. Dawn Barker is a child and adolescent psychiatric expert. She’s also a writer and a friend of mine. We’re both intrigued by the workings of the mind and feel deeply for those who suffer from mental illness and those who love them. Dawn’s new book Fractured weaves a suspenseful tale about a young woman suffering post-natal depression. It’s just been released by Hachette Australia and I can’t wait to read it.

I’ve done some research about the link between cannabis use and schizophrenia, but I’m no expert, so I asked Dawn to write an article detailing the most recent findings. Please use the comments section to ask Dawn any questions you may have. I will be!


Thrill Seekers

Thrill Seekers


Drug Abuse and Psychosis

Dr. Dawn Barker, Child & Adolescent Psychiatrist. MBChB, FRANZCP, Cert C&A Psychiatry


In Thrill Seekers, we meet a group of adolescents who – like many teenagers − use drugs recreationally. One of the main characters, Douggie, then becomes psychotic and develops schizophrenia. Many of us know a friend or family member who’s had a similar illness after drug use and are left wondering: what is the relationship between drug use and psychosis?


What is psychosis?


Psychosis refers to a group of symptoms mainly characterized by hallucinations and delusions. Hallucinations are abnormal sensory perceptions: hearing, seeing, tasting, feeling or smelling something that isn’t actually there. The sufferer might hear voices talking about them, feel insects crawling on their skin, or see faces on the wall. Delusions are abnormal, false beliefs that are held with unshakeable conviction. A deluded person may believe that they are someone special, that they are being followed, or are guilty of something terrible. A psychotic person’s speech can be difficult to follow as their thoughts are disordered, and they lose insight, that is, they are not aware that their beliefs or sensations are abnormal. This can make it very difficult to persuade a patient to seek help and accept treatment.


Most people think of schizophrenia when they think of psychosis, but that’s not necessarily the case: psychotic symptoms can occur briefly and transiently (when using drugs, or when medically unwell), or can occur as part of another psychiatric illness such as depression or bipolar disorder. If the symptoms aren’t secondary to anything and become chronic and disabling, the diagnosis changes to schizophrenia.


Drug use and psychosis


There is no doubt that drugs can cause psychosis. Some drugs – the hallucinogens like LSD and ‘magic mushrooms’ – are used to deliberately alter sensory perceptions. However, psychosis is often an unwanted reaction. As a psychiatrist, I’ve seen hundreds of patients brought into emergency departments − often by the police − with distressing, acute psychosis after abusing drugs such as amphetamines, cocaine or cannabis. Thankfully, most of these patients recover when the drug is out of their system after a few hours or days – we call this a substance-induced psychosis.

What is more worrying is the patient whose psychosis persists even after the acute effects of the drug have worn off. Some of these patients are eventually diagnosed with schizophrenia. Are drugs responsible for this?


The relationship between illicit drug use – particularly cannabis – and schizophrenia is a controversial one. Many patients with schizophrenia have used drugs, but many have not. And of course, the majority of people who use cannabis don’t develop schizophrenia. We know that people with a psychotic illness have a higher rate of cannabis use than the general population, but this could be explained by them being drawn to drug use as a way to cope with their symptoms.


As more long-term studies are analyzed, the links are becoming clearer and the most recent evidence is this:

  • If you have a psychotic illness and used cannabis in adolescence, you develop the illness 2-3 years earlier than those who didn’t use cannabis. This is significant, as we know that an earlier age of onset is associated with a poorer outcome. Using cannabis in adolescence makes you up to twice as likely to be diagnosed with schizophrenia in adulthood, and this is a dose effect: the more you use, the more likely the diagnosis is.
  • Using the drug at a younger age is most risky: cannabis use at the age of 15, but not age 18, is associated with the higher rates of schizophrenia. It’s possible that one of the chemicals released in the brain when using cannabis, dopamine, is the culprit. We use drugs that block dopamine to treat schizophrenia.
  • Cannabis use comes before psychotic symptoms appear, rather than the illness leading to more drug use.


Some people have a gene that, if present, appears to interact with adolescent cannabis use to cause psychosis. Thankfully, schizophrenia is rare, occurring in approximately 1% of the population. Cannabis use in adolescence is just one of several factors that interact to cause the illness, but it’s a significant factor that, if taken out of the equation, could reduce the rates of schizophrenia by 8%.


It’s unrealistic to expect young people to stop using cannabis completely. But we need to understand that its use in the teenage years does increase the risk of developing schizophrenia and we have no way of knowing which young person will be affected. As anyone who has suffered from – or watched someone go through − this illness will agree with, preventing even one case would make a huge difference to many lives.


For more information or if you, or a love one, need help, please contact:


1. Your local doctor or emergency department

  1. 2.  Lifeline: 131114
  2. 3.  Kids Helpline: www.kidshelpline.com.au 1800 551800
  3. 4.  Headspace: www.headspace.org.au



Large M et al. Cannabis use and earlier onset of psychosis: a systematic meta-analysis. (2011). Arch Gen Psychiatry 68(6):555-61.


Arseneault et al. Causal association between cannabis and psychosis:

examination of the evidence. (2004).  British Journal of Psychiatry 184:110-117


http://www.nationaldrugstrategy.gov.au/internet/drugstrategy/Publishing.nsf/content/C22A31B6C742DFE5CA25767E00122541/$File/m684.pdf Accessed 22/01/2013


FRACTURED by Dawn Barker

FRACTURED by Dawn Barker


Photo of Maty 1980


This is a photo of my little brother Matty, taken in 1980 or 81 when he was 12 or 13 in the first year at high school. When this picture was taken he’d already started smoking dope, as had most of his friends. A couple of years later Matty was diagnosed with full-blown schizophrenia. He killed himself not long after his twentieth birthday. Thrill Seekers is dedicated to his memory.

Matty and I were very close, only 17 months apart. I don’t remember ever feeling jealous of him or us competing for our parents’ attention. No sibling rivalry. In a snapshot taken when my mother first brought him home from the hospital I look as if I’ve just been given the most wonderful present, my own real live dolly to look after. We were good mates – the “biggies” to our younger siblings “littlies”. Matty wasn’t much chop at school but he was amazing with his hands, particularly anything mechanical. He loved animals and they loved him. One day he clambered over the fence at Lone Pine Koala Sanctuary and cuddled a wombat! He was always a risk taker. At the age of two he found Dad’s car keys and took us both on a joy ride that almost took us over a cliff. He was lots of fun.

Matty started smoking dope before me. I was worried but it seemed harmless enough. I know better now. Many researchers are stuck in the “what came first the chicken or the egg” conundrum, arguing that people with a predisposition to mental illness are drawn to cannabis and other drugs in an attempt to self-medicate. I’m not. Matty may have had a predisposition to schizophrenia (one of our father’s cousins had the disease) but surely not all of his mates did too.

Anyway, these guys were 12 and 13 years old. They weren’t self-medicating, they were playing! They’d have a smoke and play war in the long grass by the horse’s paddock or race remodelled dragsters through squirted hose water; then head up the corner shop to feast on Twisties and lollies. They were kids.

The statistics say that the chance of developing schizophrenia is one in a hundred. If there’s a relative then your odds up to 6%. But what I saw was not just one of those boys going mad – Matty was only the first. It wasn’t two of them. Not three. But MOST of them. Upping their odds to around 90%. Even those who managed to escape full blown psychosis still wrecked their health and happiness because of the destructive power of their addictions.

It isn’t just sad, it’s a tragedy. All these young men killed and damaged, as if there’d been a war.

Researcher Professor Robin Murray has found in a recent study that people are 4.5 times more likely to be schizophrenic at 26 if they were regular cannabis smokers at 15, compared to 1.65 times for those who did not report regular use until age 18.

The risk is much greater the younger you start using.

It wasn’t, and isn’t, just Matty and his mates but other clusters of kids in developed societies all over the world. Boys, and girls too, mucking around, being tough, playing cool, searching for thrills and instead finding only the torture of mental illness.

Further criminalisation of cannabis isn’t the answer. It hasn’t worked. It won’t.

Kids need to know what they’re risking when they start having bongs for breakfast.

They need to know there’s nothing cool about going crazy.

 Schizophrenia fact sheet http://www.sane.org/information/factsheets-podcasts/187-schizophrenia

INTERVIEW WITH ROBIN MURRAY http://www.youtube.com/watch?v=4KPB7fCth6U

SCHIZOPHRENIA AND STREET DRUGS article http://www.schizophrenia.com/prevention/streetdrugs.html

 For further info or support see these sites.

Beyond Blue  http://www.beyondblue.org.au    Community Services: http://www.communityservices.qld.gov.au/youth/

Youth Affairs Network: http://www.yanq.org.au  CYMHS: http://www.health.qld.gov.au/rch/professionals/cymhs.asp#service

 Headspace: http://www.gpqld.com.au/page/Programs/Mental_Health/headspace/ Mental Illness Fellowship: http://www.mifa.org.au/mifq/

Schizophrenia Fellowship Qld:http://www.mycommunitydirectory.com.au/Queensland/Gold_Coast/Health_Services/Psychiatric_Services/101021/Mental_Illness_Fellowship_Of_Queensland__Schizophrenia_Fellowship_of_QLD_Inc_-_Gold_Coast_/?aid=Lifeline

 Black Dog: http://www.blackdoginstitute.org.au  NISAD http://www.nisad.org.aub  SANE http://www.sane.org  DRUG ARM http://drugarm.com.au