Cannabis hospital admissions in Victoria were 49 per cent higher in 2022/2023 than a decade earlier. The study behind that figure examined every public and private hospital episode in the state. Published in the journal Addiction, the research by Myfanwy Graham and colleagues at Monash University counted 39,565 admissions between July 2013 and June 2023. Nearly all of them carried a mental health or behavioural diagnosis.
What Cannabis Hospital Admissions Reveal About Victoria
The 49 per cent figure applies to admissions where cannabis was the principal diagnosis, meaning the first reason listed on the record. There were 7,263 of those, or 18.4 per cent of the total. The age standardised rate rose 49.0 percent between 2013/2014 and 2022/2023, with a 95 per cent confidence interval of 26.5 to 75.6 per cent. Counting every admission with any cannabis related diagnosis, the rise was 50.4 per cent.
The trend was not a straight line. Rates peaked at 72.4 per 100,000 people in 2017/2018 and again at 77.3 in 2020/2021 before easing. The authors suggest the pandemic played a part. They point to lockdown stress, income loss and a home grown cannabis supply that kept flowing while other drug supplies faltered. Exploratory is the authors’ own word for the work, since the analysis plan was not pre-registered.
Psychosis sits at the centre of the findings. Psychotic disorder was the most common principal diagnosis, accounting for 2,909 admissions or 40.1 per cent. Harmful use followed at 15.2 per cent. Overall, harmful use made up 58.7 per cent of all cannabis related admissions, withdrawal 17.8 per cent and psychotic disorder 14.6 per cent. Poisonings and intoxication, by contrast, each fell below 5 per cent.
Even where cannabis was not the principal diagnosis, 61.5 per cent of stays were mainly for a mental or behavioural disorder. Schizophrenia topped that list with 3,999 cases. The authors read this as evidence of mental health comorbidity and polysubstance use.
Young People and Women in the Frame
Age matters here. Rates of cannabis hospital admissions were highest among people aged 15 to 24. For principal diagnosis cases, males in that group recorded 36.9 per 100,000 and females 20.5. Across all cannabis related cases, the rates reached 145 for young males and 110 for young females.
Males still account for most cases, yet the gap is narrowing. Principal diagnosis admissions rose 75.1 per cent among females, compared with 34.6 per cent among males. The authors connect this with survey data. Past year cannabis use among females climbed from 7.6 to 9.8 per cent over the period. They single out people under 25 and females of childbearing age as groups that need evidence based education and public health action.
The biggest percentage jumps appeared among adults aged 65 and over. Across all cases, rates rose 252.7 per cent for men and 411.3 per cent for women. However, older adults made up under 1 per cent of the sample, so the raw numbers stay small.
Long Stays and a Heavy Cost
Cannabis hospital admissions are not quick check ins. Of all admissions, 67.6 per cent were multi day stays with a median of seven days. Among principal diagnosis cases, 58.0 per cent ran longer than a day. The authors contrast this with national figures, where nearly two thirds of hospital admissions are same day.
Intensive care adds to the picture. All told, 1,592 admissions included an ICU stay of an hour or more, adding up to 109,881 ICU hours. In addition, there were 53 deaths over the decade, with fewer than five where cannabis was the principal diagnosis.
Money follows beds. The paper cites a 2015/2016 estimate of $128,511,008 for inpatient hospital care and more than $700 million across the wider health system. Future research, the authors add, could work out the costs from 2016 onward.
Liberalisation Without a Safety Net
The study does not set out to judge drug policy, and it cannot prove that looser rules caused the rise. Still, it does not sit in a vacuum. The authors note that most North American and European studies report increases in cannabis related hospitalisations after policies that expanded access. Australia, they say, offers a unique case, with a decade of federally regulated medical access and no legal recreational market. Even so, cannabis hospital admissions in Victoria point up.
That deserves a hard look from anyone who believed liberalisation and a low harm approach could go together. The bargain on offer was simple: relax the stance, focus on managing use, and the damage will shrink. Nothing in these figures suggests the bargain paid off, although the study cannot test the claim either way. What it does show is psychosis leading the diagnoses and young people carrying the highest rates.
Equally telling is what the data cannot show. The paper records that 87.3 per cent of admissions ended with a return to private residence. Yet it holds no information on whether treatment, counselling or recovery support came next. It counts admissions rather than people, so repeat episodes sit inside the totals. The authors also warn that harm is probably underestimated, because stigma affects disclosure and clinicians vary in how they screen and record. A system that cannot see who is falling through the gaps is poorly placed to close them.
Medicinal Is a Label, Not a Safety Rating
Federal legalisation of medicinal cannabis arrived in 2016, followed by rapid growth in prescription approvals. The introduction mentions media reports of clinicians worried about hospital presentations linked to prescribed medicinal cannabis, while admitting that little peer reviewed analysis exists. Then the limitations section lands the sting. Cannabis hospital admissions data cannot show whether use was medical or non-medical, or whether the product came from a prescription, a diversion or the street. Product strength, dose and form are invisible too.
Be clear about what that means. The study cannot say that medicinal prescribing drove any of the increase, and fairness demands saying so plainly. But the gap is the point. Sticking the word medicinal in front of cannabis has not changed the pharmacology of a psychoactive drug. It has changed perception, lending clinical respectability to a product that can still end with someone in a psychiatric bed. Beyond that, it has blurred the line between prescription supply and street supply so thoroughly that the health system cannot count them separately. A label meant to bring order has added to the confusion.
The authors themselves say it is unknown how far higher THC prescription use translates into undesirable patient outcomes. They offer their decade of data as a baseline for what comes next.
Why Cannabis Related Hospitalisations Demand a Prevention Response
The authors call for evidence based public health measures to reduce harm, along with targeted research and clinical attention. They stress that cannabis use and use disorder are modifiable risk factors for mental illness. In other words, modifiable means preventable.
A serious response starts upstream. Honest education comes first, for people under 25 and for women of childbearing age, the two groups the authors single out. Early intervention should arrive before use becomes harmful use, which already accounts for most diagnoses. Recovery pathways need to carry on once the hospital door closes. Records should capture which product, at what dose and from what source, so the next decade of cannabis hospital admissions data is not working blind.
Every one of those 39,565 admissions came after prevention had already failed.
Dalgarno Institute
Source: A decade of cannabis‐related hospital admissions in Victoria, Australia: A retrospective observational study – Graham – Addiction – Wiley Online Library