Ketamine therapy has gained national attention as a powerful, fast-acting treatment for conditions like treatment-resistant depression, PTSD, anxiety, and chronic pain. While many people have experienced profound benefits, not everyone is a good candidate for ketamine therapy.
Like all medical treatments, ketamine therapy is not suitable for everyone. Administering it to the wrong individual can lead to serious side effects, worsened mental health, or life-threatening complications.
In this guide, you’ll learn who should avoid ketamine therapy, why it’s risky for certain individuals, and what alternative treatments may be more appropriate. If you’re considering ketamine, this information will help you make an informed, safe, and responsible decision.
Key Takeaways: Who Should Avoid Ketamine Therapy
- Not everyone is a good candidate for ketamine therapy — thorough screening is essential for safety and success.
- People with a history of psychosis or schizophrenia should avoid ketamine, as it may worsen hallucinations or delusions.
- Individuals with uncontrolled heart conditions or high blood pressure are at risk due to ketamine’s stimulant effects.
- Pregnant or breastfeeding women should not undergo ketamine therapy due to unknown risks to the fetus or infant.
- Those with active substance use disorders may misuse or become dependent on ketamine and should not receive treatment.
- Teens, children, and individuals with severe liver or kidney issues are not recommended for ketamine therapy due to limited safety data.
- Certain medications, such as MAOIs and benzodiazepines, can interact negatively with ketamine and must be reviewed.
- Emotional readiness and the ability to give informed consent are critical — patients must be stable and supported throughout treatment.
- Safer, evidence-based alternatives like CBT, TMS, and EMDR are available for those who are not eligible for ketamine.
What Is Ketamine Therapy?
Ketamine was originally developed in the 1960s as an anesthetic for surgery and emergency medicine. In recent years, researchers discovered that low-dose ketamine — especially when administered under medical supervision — can offer rapid relief from severe depression and other mental health disorders.
How It Works:
Ketamine works differently than traditional antidepressants. Instead of acting on serotonin or dopamine, it targets glutamate, a neurotransmitter that plays a key role in mood, memory, and learning. By disrupting negative thought patterns and enhancing neuroplasticity, ketamine can “reset” certain brain circuits, offering new hope to those who haven’t responded to conventional treatments.
It’s typically delivered through:
- IV infusions
- Nasal sprays (like Spravato®)
- Intramuscular injections
- Sublingual lozenges
But as powerful as it is, ketamine is not for everyone — and responsible clinics always screen patients carefully.
Why Screening for Ketamine Therapy Is So Important
While ketamine has helped thousands of patients reclaim their lives, it’s not a one-size-fits-all solution. Giving ketamine to the wrong individual could lead to:
- Dangerous changes in blood pressure
- Worsening mental health symptoms
- Drug interactions
- Dependency or misuse
- Emotional destabilization
Ethical, experienced providers insist on a thorough medical and psychological assessment before starting treatment. Screening protects both the patient and the treatment provider.
Let’s explore the specific cases where ketamine therapy may do more harm than good.
1. People with Psychotic Disorders (or History of Psychosis)
One of the most well-known contraindications for ketamine therapy is in individuals with psychotic disorders, including:
- Schizophrenia
- Schizoaffective disorder
- Severe bipolar disorder with psychotic features
Why It’s a Concern:
Ketamine is a dissociative medication, meaning it can alter perceptions of reality. For someone with a history of delusions or hallucinations, ketamine may worsen their symptoms or even trigger a psychotic episode.
Clinical Insight:
Most psychiatric guidelines advise against ketamine for anyone with active psychosis. Even if the psychosis is well-managed, it’s crucial to proceed with extreme caution — if at all.
2. Individuals with Uncontrolled Heart Conditions
Ketamine stimulates the central nervous system, often leading to a temporary increase in heart rate and blood pressure, which is manageable for most people—but not for those with cardiovascular problems.
At-Risk Conditions:
- Uncontrolled high blood pressure (hypertension)
- Arrhythmias or irregular heartbeat
- History of stroke or aneurysm
- Congestive heart failure
- Coronary artery disease
Why It Matters:
For people with existing heart issues, these temporary spikes in blood pressure could lead to a medical emergency during or after the session. Proper heart health screening is non-negotiable before ketamine is considered.
3. Patients with Active Substance Use Disorders
Though ketamine is being studied as a treatment for certain addictions, it is not suitable for people who are currently using or abusing substances such as:
- Alcohol
- Cocaine
- Methamphetamines
- Benzodiazepines
- Prescription opioids
Why It’s Risky:
Ketamine is a controlled substance with its abuse potential. When taken outside of medical supervision, it can lead to psychological dependence. Individuals struggling with addiction are more likely to misuse ketamine or seek it for the wrong reasons.
Important Note:
Patients in long-term recovery may still be considered for ketamine therapy — but only under strict clinical monitoring and with full transparency about their history.
4. Pregnant or Breastfeeding Women
There is currently not enough research on the safety of ketamine use during pregnancy or while breastfeeding.
Potential Concerns:
- Possible impact on fetal brain development
- Transmission of ketamine through breast milk
- Unknown long-term effects on infants
Until more data is available, most responsible clinics do not recommend ketamine for pregnant or nursing mothers. The potential risks to the baby outweigh the capability of mental health benefits to the mother.
5. Children and Teens (Under 18)
Although there is growing interest in ketamine therapy for teens with severe depression, the FDA has not approved ketamine use for individuals under 18 (with rare exceptions in pain management or clinical trials).
Why Children Are at Risk:
- Developing brains are more vulnerable to dissociative effects
- Emotional and behavioral consequences are harder to predict
- Long-term safety data is limited
For teens, alternative therapies like Cognitive Behavioral Therapy (CBT), DBT, or medication should be explored first.
6. Individuals with Severe Liver or Kidney Disease
Ketamine is primarily processed by the liver and eliminated by the kidneys. When either of these organs isn’t working at its best, it can disrupt the body’s ability to effectively metabolize or eliminate the drug. This can lead to serious implications for how medication works in our system.
Conditions of Concern:
- Cirrhosis
- Hepatitis
- Fatty liver disease (advanced stages)
- Chronic kidney disease or renal failure
Improper processing of ketamine can lead to drug toxicity, confusion, and longer-lasting side effects. Blood work to assess liver and kidney function is often required before starting therapy.
7. Patients Taking Certain Medications
Ketamine may interact negatively with some prescription medications, either reducing its effectiveness or causing dangerous side effects.
Drug Interactions to Watch:
- Benzodiazepines: Can dull the antidepressant effects of ketamine
- MAOIs (monoamine oxidase inhibitors): Risk of dangerously high blood pressure
- Antipsychotics: May block ketamine’s therapeutic effects
- Sedatives or opioids: Increased risk of excessive sedation or respiratory issues
Always provide your provider with a complete medication list, including supplements and over-the-counter drugs.
8. Individuals with Poor Emotional Regulation or No Support System
Even if a person is physically cleared for ketamine, they still need to be emotionally and psychologically prepared.
Red Flags:
- Lack of follow-up therapy or support
- History of impulsive or high-risk behavior
- Unrealistic expectations of an “instant cure”
- Inability to cope with strong emotional experiences
Ketamine can surface suppressed emotions or trauma. Without proper integration or therapeutic support, this experience could be destabilizing rather than healing.
9. Those Unable to Give Informed Consent
Informed consent means understanding the potential risks, benefits, and alternatives before starting treatment. If someone cannot fully comprehend or agree to treatment, they should not receive ketamine.
Situations Where Consent Is Not Valid:
- Severe cognitive impairment (e.g., dementia)
- Intellectual disabilities without a legal guardian
- Non-English speakers without an interpreter
- Coercion or external pressure
Ethical ketamine clinics always prioritize patient autonomy and mental competence.
Alternatives to Ketamine Therapy
If ketamine isn’t right for you, there are many safe and effective treatments for depression, anxiety, PTSD, and chronic pain.
Evidence-Based Alternatives:
- Cognitive Behavioral Therapy (CBT)
- Dialectical Behavior Therapy (DBT)
- Eye Movement Desensitization and Reprocessing (EMDR)
- TMS (Transcranial Magnetic Stimulation)
- SSRIs or SNRIs
- Electroconvulsive Therapy (ECT) (for severe cases)
A licensed mental health professional can help build a personalized plan based on your medical history, lifestyle, and treatment goals.
Final Thoughts: Is Ketamine Therapy Right for You?
Ketamine therapy holds incredible promise, but it’s not suitable for everyone. By understanding the conditions, medications, or personal histories that make someone a poor candidate, you can protect yourself — or a loved one — from unnecessary risks.
Always consult with a licensed, experienced provider who performs full screenings, explains the risks clearly, and offers alternatives if needed. Mental health treatment is not about trends — it’s about trust, safety, and long-term healing.
FAQs
Q: Can I try ketamine if I’m already taking antidepressants?
A: In some cases, yes — but it depends on the type of medication. Your provider must review your current prescriptions for potential interactions.
Q: Will ketamine therapy make me feel high or out of control?
It’s normal to feel a bit dissociated or emotionally vulnerable, but rest assured, being in a medical setting means you’re in a safe environment with professionals monitoring your well-being.
Q: How many sessions will I need?
A: Many patients begin with 6 infusions over 2–3 weeks, followed by maintenance sessions. Every plan is personalized.
Q: What’s the difference between ketamine and Spravato?
A: Spravato is an FDA-approved nasal spray form of esketamine, typically used in a clinical setting for treatment-resistant depression.
