Eating disorders and schizophrenia have historically been studied separately. The patient populations are different, the treatment teams are different, and even the diagnostic manuals describe them in different chapters. But the overlap is real, often missed, and clinically important. People with schizophrenia have higher-than-average rates of binge eating, restrictive eating, and food-related delusions, and they often face greater barriers to getting help for these symptoms.
Eating disorders in schizophrenia can be primary (a separate diagnosis), secondary to delusions (e.g. fear of poisoned food), or driven by medication side effects — and each pattern has a different treatment.
The DSM-5-TR landscape
The DSM-5-TR's "Feeding and Eating Disorders" chapter includes anorexia nervosa, bulimia nervosa, binge eating disorder, avoidant/restrictive food intake disorder (ARFID), and a few others. Each requires specific behavioural and (for anorexia) weight criteria, plus impairment. Read NIMH's overview at nimh.nih.gov/eating-disorders.
Three patterns to watch for
1. Eating disorder as a primary, separate diagnosis
A person can have both schizophrenia and a true eating disorder. Studies suggest that 1–4% of people with schizophrenia meet criteria for anorexia or bulimia at some point — modestly higher than the general population. The treatment for these cases is fairly conventional: nutrition rehabilitation, eating disorder-focused therapy, and continued antipsychotic care.
2. Restrictive eating driven by delusions
Some people with schizophrenia stop eating because of paranoid or somatic delusions: the food is poisoned, contaminated, or sending messages; the digestive system has shut down; eating is forbidden by spiritual beings. This is not anorexia in the eating-disorder sense — there is no body image disturbance — but the medical risks are the same. Refusal to eat in psychosis is a medical emergency.
Someone you love is refusing food or fluids for more than 24–48 hours because of delusional beliefs. Call their psychiatrist, a mobile crisis team, or 911 if there are signs of dehydration or medical instability.
3. Binge eating driven by antipsychotics
Several antipsychotics — particularly olanzapine, clozapine, quetiapine, and risperidone — substantially increase appetite and food cravings. A subset of patients develop true binge eating patterns, often around carbohydrates and sugar. This contributes to the well-known weight gain associated with these medications. See antipsychotic weight gain management.
What clinicians actually look for
- Body image distortion — central to anorexia, absent in delusion-driven food refusal.
- Fear of weight gain — central to anorexia and bulimia, absent in psychosis-driven restriction.
- Compensatory behaviours — purging, laxative misuse, excessive exercise — point to bulimia or anorexia.
- Bizarre delusions about food — poisoning, divine instructions — point to psychosis.
- Pattern timing — symptoms only during psychotic episodes vs. continuous.
Why this overlap is under-treated
- Eating disorder programmes often exclude patients with active psychosis.
- Psychiatric units may not have nutrition or eating disorder expertise.
- Antipsychotic-driven binge eating is often dismissed as "just a side effect" rather than addressed.
- Patients may not bring up eating issues, focusing on more visible psychotic symptoms.
Treatment in practice
The general approach combines:
- Medical stabilisation first — for severe restriction, this may mean inpatient care.
- Antipsychotic optimisation — switching to a more weight-neutral antipsychotic if binge eating is driven by medication. Lurasidone, aripiprazole, ziprasidone, and brexpiprazole are typically more weight-neutral than olanzapine or clozapine.
- Nutrition counselling and structure — predictable meal times, balanced macronutrients, planned snacks.
- Therapy — adapted CBT for binge eating; family-based treatment for adolescents with anorexia; CBT for psychosis for delusion-driven restriction.
- Metformin — has evidence for reducing antipsychotic-driven weight gain and may indirectly reduce binge urges.
The UK's NICE eating disorders guideline (NG69) covers general management.
Special considerations
Pica — eating non-food items — occurs in some people with schizophrenia, particularly those with intellectual disability. It can lead to gastrointestinal damage and lead poisoning and warrants urgent attention.
Polydipsia — compulsive water drinking — can produce dangerously low sodium and is more common in chronic schizophrenia than is generally recognised.
The bottom line
If you have schizophrenia and your relationship with food has changed — whether you're eating constantly, restricting, or skipping meals because of delusions — it's worth raising at your next appointment. Eating problems are treatable, but only if they're named.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.