Who Should NOT Take Psychedelics: Contraindications and Risks

Why This Discussion Matters

As public interest in psychedelic therapy grows, it is essential to discuss who should NOT undergo these treatments. While research shows remarkable therapeutic potential, psychedelics are not appropriate for everyone. Proper screening and patient selection are fundamental to safe, effective treatment.

This article covers the major contraindications — conditions or circumstances where psychedelic use could cause serious harm.

Absolute Contraindications

Psychotic Spectrum Disorders

The most critical contraindication is a personal or family history of psychotic disorders:

Schizophrenia — Psychedelics can trigger acute psychotic episodes

Schizoaffective disorder — Risk of symptom exacerbation

Bipolar disorder with psychotic features — Risk of triggering manic or psychotic episodes

First-degree relatives with schizophrenia — Genetic vulnerability to psychosis may be activated

Research tracked on PsiHub consistently excludes individuals with these conditions from clinical trials. The mechanism involves 5-HT2A receptor overactivation in individuals with altered dopamine/serotonin system dynamics.

Cardiovascular Conditions (for specific substances)

Different psychedelics pose different cardiovascular risks:

MDMA (details on PsiHub):

Uncontrolled hypertension

Cardiac arrhythmias

Recent myocardial infarction

Severe heart valve disease

Ibogaine (details on PsiHub):

Any pre-existing cardiac condition

Long QT syndrome

Family history of sudden cardiac death

Use of QT-prolonging medications

Psilocybin and LSD carry lower cardiovascular risk but can still elevate heart rate and blood pressure temporarily.

Pregnancy and Breastfeeding

All psychedelics are contraindicated during pregnancy:

Potential teratogenic effects (insufficient safety data)

Uterine contraction risk (particularly with ergoline compounds like LSD)

Unknown effects on fetal neurodevelopment

Ethical impossibility of conducting safety studies

Relative Contraindications

Medication Interactions

Several common medications create dangerous interactions:

SSRIs (Selective Serotonin Reuptake Inhibitors):

Reduce psychedelic effects (5-HT2A desensitization)

Combination with MDMA risks serotonin syndrome

Tapering should be medically supervised

MAOIs (Monoamine Oxidase Inhibitors):

Dramatically potentiate psychedelic effects

Life-threatening serotonin syndrome risk with MDMA

Required for oral DMT activity (ayahuasca) — but must be carefully managed

Lithium:

Case reports of seizures when combined with psychedelics

Considered an absolute contraindication by most clinicians

Mechanism likely involves lithium's effects on serotonin signaling

Tramadol:

Lowers seizure threshold

Serotonergic properties increase interaction risk

Mental Health Conditions

Some conditions require careful consideration rather than absolute exclusion:

Severe anxiety disorders — Risk of panic during psychedelic experiences

Active suicidal ideation — Requires intensive monitoring and specialized protocols

Recent bereavement — Emotional vulnerability may intensify difficult experiences

Active eating disorders — Limited research; body image distortion may worsen

Borderline personality disorder — Emotional dysregulation concerns, though some research suggests potential benefits

Age Considerations

Adolescents — Brain development concerns; no clinical trials in under-18 populations

Elderly — Increased cardiovascular risk and medication interaction potential

Screening Best Practices

Responsible psychedelic therapy programs include comprehensive screening:

Psychiatric history — Detailed assessment of personal and family mental health

Medical examination — Including cardiovascular evaluation

Medication review — All current medications assessed for interactions

Blood work — Liver and kidney function, particularly for ibogaine

ECG — Mandatory for MDMA and ibogaine; recommended for all substances

Psychological assessment — Standardized measures of mental health status

The Bottom Line

Psychedelic therapy holds extraordinary promise, but it is not a universal treatment. The most important factor in safe psychedelic therapy is rigorous screening combined with professional medical supervision. Anyone considering psychedelic therapy should undergo comprehensive evaluation with a qualified clinician.

Explore substance safety profiles on PsiHub.

References

Johnson, M.W. et al. (2008). Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology.

Carhart-Harris, R.L. & Nutt, D.J. (2010). User perceptions of the benefits and harms of hallucinogenic drug use. Journal of Substance Use.

Safety and contraindication data on PsiHub