Autism Misdiagnosed as Schizophrenia for Decades: A Case Report

In one sentence

A 74-year-old man was misdiagnosed with schizophrenia for over 50 years after a brief psychotic episode at age 23, but a later reassessment revealed that his lifelong social and behavioral differences were actually due to unrecognized autism.

What the researchers did

This is a case report (a detailed description of one person's medical history) published in the journal Cureus. The authors describe a 74-year-old man whose first psychiatric contact was at age 23 following a short psychotic episode (hallucinations and delusions lasting less than a month). He was diagnosed with schizophrenia and treated with antipsychotic medication for decades, even though he never had another psychotic episode. In his early 70s, a multidisciplinary team reassessed him using developmental history, family interviews, and two standardized autism questionnaires: the Autism-Spectrum Quotient (AQ) and the Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R).

What they found

• The man scored 38 on the AQ (cutoff for autism is typically 32 or higher) and 152 on the RAADS-R (cutoff is 65), both strongly indicating autism.
• His lifelong traits included: preference for solitary activities, direct communication style with limited nonverbal cues, reduced but stable emotional expressivity, strong need for routines, focused interests (e.g., plant care), and sensory differences (tactile hypersensitivity, wearing layered long sleeves regardless of weather).
• He had no recurrence of psychosis after the initial episode, and his functioning remained stable: he worked independently from age 20 to 74, lived alone, and maintained close family relationships.
• Antipsychotic medication (perphenazine 8 mg daily) was gradually discontinued over one year with no relapse or adverse effects.
• Family history included two nieces with ADHD and broader autism traits in other relatives.

What this means for families and therapists

• For parents and caregivers: If your child has a psychiatric diagnosis that doesn't quite fit—especially if symptoms like social withdrawal or repetitive behaviors have been present since early childhood—consider asking for a developmental assessment by a team experienced in autism. A correct diagnosis can change treatment and improve quality of life.
• For therapists: When evaluating adults with long-standing psychiatric diagnoses, especially those with stable functioning and no recurrence of acute symptoms, take a thorough developmental history and use standardized autism screening tools. This case shows that autistic traits can be mistaken for negative symptoms of schizophrenia.
• Practical steps: If you or a family member has been on antipsychotics for years without clear benefit or with side effects, discuss with a psychiatrist whether a gradual dose reduction or discontinuation might be possible under close supervision, as was done here.

Limitations and what we don't know yet

• This is a single case report, so findings cannot be generalized to all people with similar histories.
• The autism diagnosis was made retrospectively in older age; it is possible that some traits were influenced by decades of living with a misdiagnosis.
• The study did not include a control group or systematic follow-up beyond the individual.
• The authors note that the case was identified in a specialized clinic, so similar cases may be missed in general psychiatric settings.
• Long-term outcomes after antipsychotic discontinuation are based on one person; more research is needed.

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This is a plain-language summary of Late Recognition of Autism Previously Diagnosed as Schizophrenia Following a Brief Psychotic Episode: A Case Report by Muacevic A., Adler J.R., Cureus (2026). Source license: CC-BY-4.0. It is not medical advice — talk to a qualified clinician before changing therapy.