Cannabis-induced psychosis treatment: the short answer
Treatment starts with stopping cannabis. Doctors then manage symptoms until THC clears the body. Agitation and insomnia get short courses of benzodiazepines such as lorazepam or diazepam. Hallucinations and delusions get antipsychotics such as haloperidol, olanzapine, or risperidone. Symptoms fade within days to weeks in most cases. Anyone who poses a risk of self-harm or harm to others needs hospital care.
What counts as cannabis-induced psychosis
The DSM-5-TR classifies these cases as substance/medication-induced psychotic disorder. Three criteria apply:
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- Hallucinations or delusions are present.
- Symptoms start during cannabis use or within one month of stopping.
- Another disorder, such as schizophrenia or bipolar disorder, does not explain the symptoms better.
Emergency departments in the US report more of these visits since state legalization. Colorado hospital data showed a rise in cannabis-related psychosis visits after 2012.
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First steps in the emergency room
- Rule out other causes: infection, head injury, thyroid disease, stimulant use, alcohol withdrawal.
- Stop all cannabis products, including edibles, vapes, and concentrates.
- Reduce stimulation: dim lights, one person speaking, no crowds.
- Screen for suicide risk and for weapons access.
Urine drug screens detect THC metabolites for days to weeks after last use. A positive screen does not prove cannabis caused the psychosis.
Medications
- Benzodiazepines: lorazepam, diazepam, or midazolam. Used for agitation, panic, and sleeplessness. Course length: hours to a few days.
- Antipsychotics: haloperidol, olanzapine, risperidone, or quetiapine. Used for hallucinations, paranoia, and disorganized speech. Doctors start at the lowest dose and stop when symptoms end.
- Antipsychotics do not speed THC clearance. They control symptoms while the drug leaves the body.
Some doctors add a short course of an antipsychotic at bedtime for sleep, then taper it over 1 to 4 weeks. Long-acting injectable antipsychotics are not a first step.
Timeline
- Hours to 3 days: peak symptoms for smoked cannabis. Edibles can hit later and last longer.
- 3 days to 4 weeks: symptoms resolve in most patients after cannabis stops.
- Past 4 weeks: symptoms point to another diagnosis, most often a schizophrenia-spectrum disorder.
Follow-up studies report that 25% to 35% of people treated for cannabis-induced psychosis receive a schizophrenia-spectrum diagnosis within 3 to 5 years. Psychiatric follow-up for at least 6 months is standard. Ask about sleep, mood, and return to use at each visit.
Risk factors for a repeat episode
- First use before age 18.
- Daily or near-daily use.
- THC concentration above 15%.
- Synthetic cannabinoids such as K2 or Spice.
- Family history of psychosis or bipolar disorder.
A 2019 study of 11 European cities linked daily use of high-potency cannabis to higher odds of psychotic disorder. People who stop cannabis after one episode cut the risk of a second.
When to call 911 or 988
Call 911 for seizures, chest pain, overheating, or threats of violence. Call or text 988 for suicidal thoughts, self-harm, or a crisis with no immediate danger. The 988 Suicide and Crisis Lifeline routes calls to trained counselors in the US.
What does not work
Sedating someone with alcohol or street drugs raises risk. So does waiting out severe paranoia at home. There is no drug that removes THC from the bloodstream faster. Time and abstinence do that.