{"id":12659,"date":"2026-07-22T21:19:58","date_gmt":"2026-07-22T11:19:58","guid":{"rendered":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/?p=12659"},"modified":"2026-07-22T21:22:38","modified_gmt":"2026-07-22T11:22:38","slug":"commercial-cannabis-legalisation-drives-addiction-and-psychosis-global-review-finds","status":"publish","type":"post","link":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/commercial-cannabis-legalisation-drives-addiction-and-psychosis-global-review-finds\/","title":{"rendered":"Commercial Cannabis Legalisation Drives Addiction and Psychosis, Global Review Finds"},"content":{"rendered":"\t\t
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\"\"A major global review has linked commercial cannabis legalisation to rising rates of addiction, psychiatric hospital admissions and cannabis use disorder. Researchers at the University of Bath led the study, published in The Lancet Psychiatry. The team tracked cannabis policy changes in dozens of countries from 2000 to 2025. One number stands out immediately: cannabis induced psychosis hospitalisations in Ontario climbed 220.7 percent after commercial retail expanded. That pattern repeats across every commercialised market the review examined.<\/p>

Why Commercial Cannabis Legalisation Behaves Differently to Decriminalisation<\/strong><\/p>

Professor Tom Freeman led the research with Dr Rachel Lees Thorne. Freeman says policy type matters more than whether change happens at all. Decriminalised countries showed little rise in cannabis use. Tightly controlled legal markets showed little rise too. Commercial cannabis legalisation broke that pattern everywhere researchers looked.<\/p>

Portugal and Czechia removed criminal penalties for possession years ago. Neither country saw a meaningful jump in use. Some regions even recorded falling hospital admissions for cannabis psychosis during periods of lower penalties.<\/p>

That picture isn\u2019t universal, though. A separate analysis covered ten policy changes across eight countries. Six of seven countries that lowered penalties, Bulgaria among them, saw a small rise in adolescent use. Larger, more rigorous studies found no consistent effect overall. Both results sit in the evidence base. Neither cancels the other out.<\/p>

Commercial Cannabis Legalisation in Canada and the United States<\/strong><\/p>

Canada legalised non-medical cannabis nationally in 2018. Past year use among adults rose from 22 percent before legalisation to 27 percent by 2020, then levelled off near 26 percent. Ontario data tells a sharper story. Emergency visits and hospitalisations for cannabis induced psychosis rose 220.7 percent between 2014 and 2021, climbing from 0.29 to 0.93 cases per 100,000 people. The sharpest rise followed the expansion of commercial retail stores and higher potency products, not the legal change itself.<\/p>

The United States tells a similar story under commercial cannabis legalisation. Most states adopted a commercial model with few limits on potency, pricing or marketing. Daily cannabis consumers in the US now outnumber daily alcohol consumers, according to Freeman. Colorado hospital data showed psychosis related visits climbing alongside dispensary numbers. Hospitalisations for psychosis rose from 28.0 to 32.3 per 100,000 people, and cases combining psychosis with cannabis use disorder more than doubled, from 3.4 to 8.5 per 100,000.<\/p>

Commercial pressure keeps pushing potency higher too. Profit driven retailers sell flower and concentrates carrying far higher THC levels than tightly regulated schemes allow. Higher potency use consistently raises the risk of both addiction and psychotic illness.<\/p>

Hospital Visits Are Not the Same as Population Wide Rates<\/strong><\/p>

This distinction matters, and it gets blurred often. Researchers did not find consistent evidence that legalisation changes the underlying prevalence of psychotic disorders across a population. What they did find was a rise in hospital admissions for psychosis, and for psychosis alongside cannabis use disorder, strongest in the most commercialised regions.<\/p>

That finding still carries real weight. More people are showing up in emergency rooms. More psychiatric beds are filling with cannabis related crises. But it\u2019s a claim about strain on health services, not a settled claim about how many people develop psychotic illness overall. Keeping that distinction clear protects the argument rather than weakening it.<\/p>

Uruguay Shows a Different Path, Backed by Thin Evidence<\/strong><\/p>

Uruguay avoided commercial cannabis legalisation entirely. Adults access cannabis only through registered home growing, nonprofit social clubs, or pharmacies. Government sets price, product range and potency in pharmacies, currently capped at 20 percent THC.<\/p>

Results compared with neighbouring Chile look encouraging. One study found no significant rise in past year or past month use following legalisation. A second study found an actual drop in past year and past month use among 12 to 17 year olds, plus a meaningful fall in high risk use among 12 to 21 year olds.<\/p>

Why the Comparison Doesn\u2019t Settle the Question<\/p>

Two published studies cover this policy, and both focus only on adolescents and young adults. Both track a short window following the 2017 rollout of pharmacy sales. Bath researchers say evidence is still needed for adults older than 21, for psychiatric outcomes, and over a longer follow up period. Uruguay hasn\u2019t visibly harmed teenagers so far. Nobody yet knows what fifteen or twenty years of a stable legal market does to adults, addiction rates or psychiatric illness.<\/p>

Uruguay\u2019s safety, so far as it holds, depends on government suppressing every commercial incentive that reshaped Canada and the US: advertising, potency competition, retail density, price cuts. Thailand shows what happens when that effort stops.<\/p>

Thailand Shows How Fast a Legal Market Can Escalate<\/strong><\/p>

Thailand removed cannabis from its controlled substances list in 2022, and a fast slide toward commercial cannabis legalisation followed almost immediately. Dispensaries multiplied within months. Inpatient cases of cannabis induced psychotic disorder rose from 477 in 2017 to 2,713 in 2023, according to Thailand\u2019s National Health Security Office, a nearly fivefold increase. Cannabis poisoning cases climbed from 39 to 637 over the same period, and acute intoxications rose from 76 to 1,039.<\/p>

Facing mounting concern, Thailand\u2019s government reversed course in June 2025. The country now restricts cannabis to medical use only and requires a medical certificate for purchase. Few countries have tested how quickly a legal market can escalate, or how hard it is to walk back once demand and retail infrastructure take hold.<\/p>

What Commercial Cannabis Legalisation Means for the UK<\/strong><\/p>

Cannabis remains a Class B controlled drug in the UK, carrying a maximum penalty of five years in prison for possession. A 2025 report from the London Drugs Commission, commissioned by the Mayor of London, proposed decriminalising possession for recreational use. It also called for shifting enforcement resources toward healthcare.<\/p>

Robust studies found little consistent link between decriminalisation and use, and the review draws a clear line between that finding and commercial cannabis legalisation, which behaves very differently. Individual country studies tell a messier story, with some, including parts of Europe, recording small increases after similar reforms. Decriminalisation changes the signal a drug sends. It reduces the friction that currently suppresses demand. Portugal shows this often becomes a first step rather than a stable endpoint.<\/p>

The Only Model With No Downside Risk<\/strong><\/p>

Cannabis policy is shifting fast across dozens of countries right now. Every jurisdiction that loosened its rules saw cannabis embed itself further into daily life. The differences between these models come down to speed, not safety. Commercial cannabis legalisation remains the fastest route to harm. It isn\u2019t the only route, though, and researchers have only tested the safest alternative on record on teenagers, over a few short years.<\/p>

Prevention and demand reduction carry no built in path toward addiction or rising psychiatric admissions. Policy debates that focus only on regulating a cannabis market well skip past the more important question: should cannabis become a normal consumer product at all?<\/p>

(Source: WRD News<\/a><\/strong>)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

A major global review has linked commercial cannabis legalisation to rising rates of addiction, psychiatric hospital admissions and cannabis use disorder. Researchers at the University of Bath led the study, published in The Lancet Psychiatry. The team tracked cannabis policy changes in dozens of countries from 2000 to 2025. One number stands out immediately: cannabis […]<\/p>\n","protected":false},"author":1,"featured_media":12658,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":"","_wp_rev_ctl_limit":""},"categories":[16],"tags":[],"class_list":["post-12659","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cannabis-conundrum"],"_links":{"self":[{"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/posts\/12659","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/comments?post=12659"}],"version-history":[{"count":1,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/posts\/12659\/revisions"}],"predecessor-version":[{"id":12662,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/posts\/12659\/revisions\/12662"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/media\/12658"}],"wp:attachment":[{"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/media?parent=12659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/categories?post=12659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dalgarnoinstitute.org.au\/wp_site\/wp-json\/wp\/v2\/tags?post=12659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}