Anxiety, Panic and Paranoia Reactions

Urgent first

Seek emergency care if someone has hallucinations, severe confusion, or thoughts of self-harm after cannabis. In the US, NIDA says to call 911 or go to an emergency department, and that Poison Control can be reached at 1-800-222-1222. [1] For a crisis, call or text 988 to reach the 988 Suicide & Crisis Lifeline. [1] For a child who may have eaten cannabis, see poisoning: what to do first and when to seek urgent help after cannabis.

How to read this page

This page is education, not medical advice. It does not give ways to "manage" or "calm" a bad reaction at home. Evidence labels: established, mixed, insufficient evidence, evidence of harm (an association in studies), preclinical. The same cannabis can feel relaxing to one person and frightening to another, and research cannot predict which.

What the reactions are

NIDA lists anxiety, fear, distrust, panic or hallucinations as short-term effects of cannabis that are more common when a person takes a large amount, the product is strong (high in THC), or the person has little experience with cannabis. [1] Health Canada lists anxiety, fear or panic among possible effects, and lists paranoia among features of psychotic episodes that cannabis can cause. [2] Cannabis can also make people feel more irritable or restless. [1]

Slow-acting products matter. Health Canada says eaten or drunk cannabis can take up to two hours to begin and up to four hours to develop fully. [3] NIDA warns that this delay can lead people to use more, increasing the likelihood of serious negative effects. [1]

Proper evidence not found: "greening out" is a popular term. A PubMed search for it returned nothing relevant, and the NIDA and NCCIH pages read for this site do not use the term, so this page does not describe it as a distinct condition. The symptoms people use that word for (nausea, dizziness, anxiety) are described in the sources above only under other names.

How common are they? Emergency department data

A retrospective study at seven emergency departments in Michigan reviewed 1,135 patients with acute cannabis toxicity over 24 months. Of these, 196 (17.3%) came in mainly with anxiety. Among the anxious group, 11.7% had panic attacks, 9.2% aggression or manic behavior, and 6.1% hallucinations. They were more likely than other cannabis patients to be younger, to have eaten an edible, to have a psychiatric condition, or to have a history of using several substances. [4] This is one region and only people who sought emergency care, so it does not show how often anxiety happens in the wider population. Label: evidence of harm (association, observational).

Anxiety after longer-term use

Different questions have different answers. A meta-analysis of studies that followed teenagers into young adulthood found cannabis use before age 18 linked to later depression (odds ratio 1.37) and suicidal thoughts and attempts, while the link to later anxiety was not statistically significant (odds ratio 1.18, range 0.84 to 1.67). [5] Label: mixed to insufficient evidence for later anxiety disorders. See cannabis and adolescents.

Cannabis and psychosis-like symptoms

A frightening, paranoid experience is not the same as a psychotic disorder, but intoxication can cause a temporary psychotic episode in some people, especially at high doses, and NIDA says such an episode may be linked with developing a psychotic disorder later. [1] See psychosis and mania vulnerability.

Is CBD different?

THC and CBD are different compounds. A 2024 systematic review of 11 randomized trials found that CBD may reduce anxiety compared with placebo with few side effects, but the trials varied widely in conditions and amounts and had often contradictory results, so more trials are needed. [6] Label: mixed. That does not mean CBD products prevent THC reactions, and the review does not say so. See cannabinoids and anxiety: evidence review.

Who should be especially careful

NIDA says people with mental health conditions and related symptoms are more likely to use cannabis, and that many shared factors such as genes, trauma and stress also influence mental health, so cause is hard to separate. [1] A 2023 BMJ umbrella review supports avoiding cannabis in people prone to or with mental health disorders. [7] Anyone with an anxiety, panic or mood condition who is considering or using cannabis should talk with their prescriber or clinician, and should not stop or change medicines on their own.