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

The takeaway

A systematic review of case reports found delta-8-THC is associated with psychosis, mood instability, and other psychiatric symptoms, particularly in young males, despite being marketed as a gentler alternative.

Consumers considering delta-8 products, emergency physicians, substance use counselors, cannabis regulators.

9 patients with delta-8-THC psychiatric symptoms

What the researchers found

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.

Why it matters

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 numbers in context

201 studies screened. 12 met inclusion. 6 case reports with 9 patients reviewed. Most patients male, in their 20s. Symptoms: psychosis, mood lability, cannabinoid hyperemesis syndrome. No FDA regulation.

How the study worked

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.

What this study cannot tell us

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.

How to read the evidence

Preliminary: systematic methodology but limited to a small number of case reports, the lowest level of clinical evidence.

When this study was published

2025 study

The bigger picture

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.

Questions still open

What is the actual incidence of psychiatric adverse events from delta-8-THC? Is delta-8-THC truly less risky than delta-9, or just less studied? Should delta-8-THC be regulated the same as delta-9?

Common questions

Is delta-8-THC safe?

This review found case reports of psychosis, mood instability, and other psychiatric symptoms from delta-8-THC use. While it is marketed as milder than regular THC, it carries real psychiatric risks, especially without FDA regulation or quality controls.

Can delta-8-THC cause psychosis?

Yes. Six case reports documented psychosis and other psychiatric symptoms in 9 patients using delta-8-THC, including some with no prior psychiatric history.

Read the original research

Evaluating Delta-8-THC-Induced Psychosis: A Systematic Review.

Clinical neuropharmacology, 48(1), 20-23

View on PubMed ↗Publisher’s paper ↗

Citation

Ralston, Megan Jayne; Osman, Alim. (2025). Evaluating Delta-8-THC-Induced Psychosis: A Systematic Review.. Clinical neuropharmacology, 48(1), 20-23. https://doi.org/10.1097/WNF.0000000000000619