Delta-8-THC Can Cause Psychosis Despite Being Marketed as Milder Than Delta-9

From 201 studies screened, 12 met criteria and 6 case reports involving 9 patients were reviewed. Most patients were male in their 20s. Psychiatric histories varied from none to schizophrenia and PTSD. Reported symptoms included psychosis, mood lability, and cannabinoid hyperemesis syndrome. Despite being marketed as less intoxicating than delta-9-THC, delta-8-THC posed significant psychiatric risks.

Systematic review following PRISMA guidelines, searching PubMed and Web of Science for studies on delta-8-THC and psychosis. Articles on delta-9-THC or other cannabinoids were excluded. 201 studies identified; 12 met inclusion for full-text analysis; 6 case reports (9 patients) were reviewed. Quality assessed using CASP Checklist for Case Reports.

Delta-8-THC products are widely available in the U.S. due to the 2018 Farm Bill loophole, often marketed as a safer, legal alternative to regular cannabis. This review documents that delta-8-THC carries real psychiatric risks, particularly concerning given the lack of FDA regulation and easy consumer access.

The delta-8-THC market exploits a regulatory gap: it is derived from hemp (legal under the Farm Bill) but produces psychoactive effects. The documented psychiatric risks, combined with the absence of quality controls, dosing standards, or age restrictions in many states, create a public health concern that regulatory frameworks have not addressed.

Limited to case reports (lowest level of evidence). Only 9 patients across 6 reports. Cannot determine incidence or prevalence of psychiatric effects. Publication bias toward severe cases. No controlled comparisons with delta-9-THC. Cannot establish causation from case reports alone.