1. Long-Term Effects on Brain Chemistry

• Marijuana (THC): Can induce cannabis-induced psychosis in some individuals, and long-term use increases the risk of developing schizophrenia in those with a predisposition.
• MDMA (Ecstasy): Can cause long-lasting changes in serotonin levels, which may contribute to anxiety, depression, and even psychotic symptoms in some individuals.
• Amphetamines (Speed, Pervitin): These can sensitize dopamine receptors, meaning the brain may become more prone to psychotic episodes even after stopping use.

2. Stress as a Trigger

• Drug-induced changes in brain chemistry may leave some people more vulnerable to psychosis, which can surface under stress even months later.
• Previous drug use + stress can lead to a relapse of drug-related psychosis or trigger an underlying psychiatric disorder like schizophrenia or bipolar disorder.

3. Individual Susceptibility

• Genetics & predisposition: Those with a family history of schizophrenia or other mental illnesses are at much higher risk.
• Previous psychotic episodes: If someone has experienced drug-induced psychosis before, stress alone can sometimes re-trigger it.
• Polysubstance use & frequency: Higher and more frequent drug use increases the likelihood of lingering effects.

4. Neurotoxicity & Persistent Symptoms

• Chronic amphetamine/methamphetamine use can lead to persistent psychotic symptoms (hallucinations, paranoia) even after stopping.
• THC can accumulate in fat cells, meaning occasional users may have traces in their system for weeks, though this is less of a factor months after stopping.

Bottom Line

Yes, even after months of abstinence, psychotic symptoms can re-emerge due to stress if the brain has been previously affected by drug use. This is more common in individuals who are predisposed or have experienced drug-induced psychosis before. If you or someone you know is experiencing symptoms, seeking medical advice is strongly recommended.