Potential Iatrogenic Harms From Medicinal Cannabis Prescribing in Australia: A Case Series.

Bradlow R.; Sorensen J.; Cunningham A.; Daugherty S.; Hadinata E.; Armstrong F.; Jamshidi N. · Drug and alcohol review · 2026

**Background & Methods** This is a case series describing three young men (aged 20-24 years) with pre-existing psychiatric disorders and substance use vulnerabilities who were prescribed medicinal cannabis in Australia. The study illustrates potential iatrogenic harms associated with current prescribing practices in this vulnerable population. **Key Findings** • Multiple adverse psychiatric and medical outcomes emerged in all three cases, including cannabinoid hyperemesis syndrome, cannabis use disorder, paranoia, and affective instability, with treatment delays for other indicated interventions occurring in at least two cases. • Prescribing continued despite documented adverse outcomes and, in two cases, formal cessation requests from addiction specialists, suggesting inadequate safety monitoring and patient-provider communication. • The cases underscore risks associated with commercialised medicinal cannabis prescribing models in Australia, particularly among patients with psychiatric comorbidities and substance use vulnerabilities where evidence of benefit is limited. **Dosage & Administration** Not reported. **Safety & Adverse Effects** The case series documents multiple serious adverse effects: cannabinoid hyperemesis syndrome (recurrent nausea and vomiting), cannabis use disorder (escalating use patterns despite harms), paranoia, and affective instability. Additionally, prescribing delays appeared to postpone initiation of evidence-based psychiatric treatments in affected individuals. The cases highlight that adverse outcomes were not consistently managed by discontinuation, with prescribing continuing despite clinical deterioration and explicit requests from addiction specialists to cease treatment. **Evidence Quality** This is a case series, representing Level 4 evidence—the lowest tier of clinical evidence hierarchy. Significant limitations include the small sample size (n=3), lack of control group, absence of systematic data collection, and inability to establish causality or generalise findings to broader populations. The study relies on retrospective case documentation without standardised outcome measurement. However, the cases are clinically illustrative and raise important safety concerns. The authors appropriately acknowledge that medicinal cannabis evidence for psychiatric indications is of "low certainty," and this case series adds descriptive evidence of potential harms rather than efficacy data. Generalisability is limited to similar clinical contexts in Australia's current prescribing environment, and individual susceptibility factors cannot be determined from case descriptions alone. The findings support the need for more rigorous, prospective safety studies in vulnerable populations.

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