Psychosis Doesn't Always Start in the Mind
The medical causes of psychotic symptoms that too many providers overlook — and why it matters for your family.
When someone you love starts hearing voices, seeing things that aren't there, or believing things that don't make sense — the fear is immediate. And the path that usually follows is just as fast: a psychiatric evaluation, a diagnosis, a prescription.
But what if the psychosis isn't coming from a psychiatric illness at all?
What if it's coming from the body?
This is not a fringe idea. It's supported by decades of peer-reviewed research, including a major 2025 meta-analysis that found the problem is far more common than most providers acknowledge.
The Numbers That Should Concern Every Parent
In January 2025, World Psychiatry published a landmark systematic review and meta-analysis by Blackman and colleagues analyzing 33 independent studies and over 26,500 patients. Their conclusion: roughly 1 in 9 patients with psychosis (11%) had a secondary cause — meaning their psychosis was caused by something other than a primary psychiatric disorder.
When they narrowed the analysis to first-episode psychosis only, that number climbed to 1 in 7 (14%).
The clinical setting matters enormously. In general hospital settings, 38% of patients presenting with psychosis had a secondary cause. In psychiatric settings, where the assumption of a primary psychiatric disorder is already baked in, the number dropped to just 7%. That gap alone tells you something important about what can be found when someone actually looks.
Perhaps the most striking finding: when urine analysis was routinely performed as part of the workup, the estimated rate of secondary psychosis jumped to 23%. The implication is clear. The more thoroughly you test, the more you find.
This isn't an isolated finding. A Johns Hopkins study found that roughly half of patients referred to their Early Psychosis Intervention Clinic with a schizophrenia spectrum diagnosis did not actually have schizophrenia. Out of 78 patients evaluated between 2011 and 2017, the majority of those who arrived with a schizophrenia diagnosis received a different one after thorough reassessment — and many weren't diagnosed with a primary psychotic disorder at all. A separate study of patients with severe psychiatric disorders found that over 39% were misdiagnosed, with schizoaffective disorder misidentified 75% of the time.
It Starts in the Body More Often Than We Think
A 2025 study published in Annals of Clinical and Translational Neurology examined 642 patients with confirmed encephalitis (inflammation of the brain) across two major hospital systems. Nearly half (49.6%) presented with psychiatric symptoms as their initial complaint. Among patients with autoimmune encephalitis specifically, that number rose to 78.2%. These patients showed up looking like they had a psychiatric illness. Many of them were initially treated as though they did.
In anti-NMDA receptor encephalitis, the condition made famous by Susannah Cahalan's memoir Brain on Fire , 77% of patients see a psychiatrist first, and roughly a third are initially assessed in a psychiatric department rather than a medical one. The psychiatric symptoms (hallucinations, paranoia, agitation, bizarre behavior) can be indistinguishable from schizophrenia. But the treatment couldn't be more different: immunotherapy, not antipsychotics.
A 2025 study from China Medical University documented cases of organic neurological disorders that had been misdiagnosed as psychiatric conditions, finding that the misdiagnosis led to wasted medical resources and significant treatment delays, time during which the actual condition continued to progress.
Why Does This Keep Happening?
There is still no universally agreed-upon standard for the initial medical workup of first-episode psychosis. As recent as 2023, a review from Columbia University proposed the first consensus-driven clinical pathway for pediatric psychosis specifically because no standard existed.
When a patient presents with hallucinations or delusions, the clinical reflex is often to reach for a psychiatric diagnosis first and investigate medical causes second, if at all. Schizophrenia is technically a diagnosis of exclusion, meaning medical causes should be ruled out before it's diagnosed. But in practice, this step is frequently skipped or incomplete.
A 2022 study of 131 children and adolescents hospitalized for new-onset psychosis found that while most were ultimately given a primary psychiatric diagnosis, 25% had incidental medical findings unrelated to psychosis, and nearly 11% had findings that required medical intervention. These weren't rare edge cases, they were children whose medical issues would have been missed entirely without a thorough workup.
The consequences of missing these causes are serious. When a medical condition is driving psychotic symptoms and it goes unidentified, the patient may spend months or years on psychiatric medications that don't address the actual problem, medications that carry their own significant side effects. Meanwhile, the underlying condition continues to do damage. Research on autoimmune encephalitis has shown that patients initially misdiagnosed and admitted to psychiatry experience substantially longer delays before receiving the treatment that actually works.
What Medical Conditions Can Cause Psychosis?
The list is longer than most people expect. These aren't rare, obscure conditions. Many are well-documented, testable, and treatable.
Autoimmune and inflammatory conditions like autoimmune encephalitis, lupus, and multiple sclerosis can directly attack the brain, producing hallucinations, paranoia, and disorganized thinking that look identical to schizophrenia. A 2025 study of 195 psychotic patients found that 164 were ultimately diagnosed with psychosis of autoimmune origin and the majority experienced significant cognitive and functional improvement after receiving immunotherapy rather than antipsychotics.
Neurological conditions including epilepsy, brain tumors, cervical spine injuries, and cerebrospinal fluid leaks can all produce psychiatric symptoms. People with epilepsy are eight times more likely to experience psychosis than the general population. Brain tumors can present with psychiatric symptoms as their sole initial sign. Psychotic symptoms were found in 22% of brain tumor patients studied. These often go undetected for months.
Metabolic and endocrine conditions such as vitamin B12 or thiamine deficiency, Cushing's disease, Addison's disease, diabetic crises, toxicity from heavy metals or medications, and serotonin syndrome can all trigger psychotic episodes. In Cushing's syndrome, psychiatric symptoms are present in 20 to 83% of patients. Vitamin B12 deficiency, one of the simplest conditions to test for, is found in 6 to 15% of psychiatric patients.
Infectious causes including urinary tract infections, parasitic infections like toxoplasmosis, and post-infectious inflammation can produce psychotic symptoms through immune-mediated pathways. UTIs were found to be almost 11 times more prevalent in patients with psychosis than in control groups. Toxoplasma gondii, a parasite carried by cats that infects 30 to 65% of the global population, has been linked to increased severity of psychotic symptoms and smaller grey matter volumes in patients with severe mental illness.
Sensory and situational causes like Charles Bonnet Syndrome (visual hallucinations from vision loss) and acute medical events such as strokes, traumatic brain injuries, and ICU stays round out the picture.
The common thread: in every one of these cases, the psychosis often resolves, sometimes completely, when the underlying medical condition is identified and treated.
What This Means for Families
If your child or someone you love is experiencing psychotic symptoms, you have the right to ask whether a comprehensive medical workup has been done. Not a basic blood panel.
The 2025 World Psychiatry meta-analysis made this point clearly: when clinicians test more thoroughly, they find more secondary causes. The difference between a 7% detection rate and a 23% detection rate isn't better patients, it's better testing.
This isn't about doubting your provider. It's about making sure nothing is being missed. Because the research is clear: medical causes of psychosis are routinely overlooked, and many mental health providers are simply unaware. When they're caught, the outcome can be dramatically different.
References:
Blackman, G. et al. "How Common Is Secondary Psychosis? Estimates from a Systematic Review and Meta-Analysis." World Psychiatry, 2025.
Bean, L. et al. "Psychiatric Manifestations of Encephalitis." Annals of Clinical and Translational Neurology, 2025.
Margolis, R. et al. "Study Suggests Overdiagnosis of Schizophrenia." Journal of Psychiatric Practice, 2019. Johns Hopkins Medicine.
Misdiagnosis detection rates in severe psychiatric disorders. PMC, 2021.
"Autoimmune Encephalitis Misdiagnosis and Mimics." ScienceDirect, 2023.
"Anti-NMDA Receptor Encephalitis: A Narrative Review." Brain Sciences, 2025.
Jonokuchi, A. et al. "Approach to New-Onset Psychosis in Pediatrics: A Review of Current Practice and an Interdisciplinary Consensus-Driven Clinical Pathway." Journal of Child Neurology, 2023.
"Acute Medical Workup for New-Onset Psychosis in Children and Adolescents: A Retrospective Cohort." PMC, 2022.
"Study on the Final Diagnosis of Nervous System Diseases with Psychiatric Symptoms as Manifestation Onset." BMC Psychiatry, 2025.
"Diagnostic Transitions from Primary Psychiatric Disorders to Underlying Medical Conditions." PMC, 2024.
"Medical Mimics: Differential Diagnostic Considerations for Psychiatric Symptoms." PMC, 2018.
"First Episode Psychosis Medical Workup: Evidence-Informed Recommendations." Child and Adolescent Psychiatric Clinics of North America, 2019.
"Psychosis." StatPearls, NCBI Bookshelf.
Autoimmune Psychosis: Psychopathological Patterns and Outcome After Immunotherapy. PubMed, 2025.
A Deeper Look: 15 Root Causes of Psychosis That Deserve a Closer Look
We created a comprehensive, evidence-based resource that walks through 15 specific medical conditions that can cause or mimic psychosis, each one backed by peer-reviewed research. For every condition, we explain what it is, how it triggers psychotic symptoms, what to look for, questions to ask, and what treatment can look like when the real cause is found.
A note from TBP: At The Beta Program, we believe in looking deeper. Psychosis is a symptom, not always a diagnosis, and dozens of conditions can produce it. We're a mental health practice, and part of comprehensive mental health care is making sure the body has been heard, too. If you're navigating a new or existing psychosis diagnosis and want support, we're here.
→ Read: What Does “Root Cause” Mental Health Actually Mean?
The Beta Program, LLC is a non-medical mental health provider. The content in this post, or in any linked information or products, is intended for educational purposes only and does not constitute medical advice, diagnosis, or treatment. The opinions expressed in these articles are those of The Beta Program,LLC and have no relation to those of any health practice or other institution. If you have concerns or questions about your child’s physical or neurological health, please consult a qualified medical professional.
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