Untangling the overlap: Study reveals confusion and gaps in diagnosing autism, psychosis, and catatonia

A new international review led by researchers in Sweden and the United States has found that clinicians may be struggling to – in severe cases – tell the difference between autism, psychosis, and catatonia — three serious conditions that can sometimes appear together but require very different treatments.

The scoping review, published in the Journal of Autism and Developmental Disorders, examined decades of research and found that confusion between these diagnoses is widespread in inpatient settings, often leading to delayed or incorrect treatment.

Three disorders, one complicated picture

Autism, psychosis, and catatonia were once thought to be part of the same condition—schizophrenia. While science has since separated them, their symptoms can still overlap in striking ways.

Image

“Because these conditions share behavioural signs, it can be extremely difficult to differentiate them,” said lead author Dr. Johan Nyrenius, researcher at the Gillberg Neuropsychiatry Centre, University of Gothenburg, and at Lund University, and psychologist at the psychiatric clinic in Helsingborg, Sweden. “That uncertainty can have serious consequences for patients.”

Catatonia, for instance, can cause mutism, unusual postures, or repetitive movements — symptoms that can look similar to behaviours seen in autism. Psychosis, meanwhile, can include social withdrawal and a lack of emotional expression, which may also overlap with autistic traits.

The study found that such similarities can lead to missed or delayed diagnoses, sometimes for years. In some cases, treatments meant for one condition actually worsened another — particularly when catatonia was mistaken for psychosis and treated with antipsychotic drugs.

The review: only 17 studies worldwide

The researchers combed through 752 scientific papers published between 1980 and 2024, narrowing them down to just 17 that directly examined patients showing all three conditions.

Most of these were small case reports or short studies — and failed to clearly explain how clinicians diagnosed each disorder.

Only a handful used standardised diagnostic tools. While most researchers used structured tests for catatonia, few did so for psychosis, and many relied on vague or overlapping descriptions.

In other words, even the research community is not fully sure how to tell these conditions apart.

What the studies found

The review’s qualitative analysis identified four recurring themes:

• Catatonia as the common thread – In many cases, catatonia seemed to sit at the intersection of autism and psychosis, with overlapping features from both.
• Delayed diagnoses – Catatonia was often overshadowed by autism or psychosis, leading to missed or late recognition.
• Treatment uncertainty – There was no clear agreement on how to treat patients showing true co-morbidity of all three conditions. Some improved with benzodiazepines or electroconvulsive therapy (ECT), while others did not improve or even worsened.
• Unclear biological causes – A few papers suggested genetic links, such as mutations in the SHANK3 gene or trisomy 21 (Down syndrome), but no biomarkers were confirmed.

Treatment: a risky balancing act

The studies highlighted concerning treatment risks. In several reports, antipsychotic medications — normally prescribed for schizophrenia — worsened catatonic symptoms such as mutism, immobility, or rigidity.

In contrast, treatments like lorazepam (a sedative) and ECT often produced rapid improvements, particularly when catatonia was correctly identified early.

“Recognising catatonia quickly is crucial,” the authors wrote. “Treating it as psychosis can lead to deterioration, not recovery.”

Why it matters

The consequences of diagnostic confusion can be severe. A misdiagnosed patient may spend months or even years on the wrong medication or go untreated.

The researchers call for new diagnostic guidelines, better training for clinicians, and large-scale studies to evaluate the clinical utility of structured tools such as the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS), the Positive and Negative Syndrome Scale (PANSS), or the Brief Psychiatric Rating Scale (BPRS).

They also argue for a need to develop treatment algorithms that can safely guide clinicians when a patient appears to have overlapping symptoms of autism, psychosis, and catatonia.

A call for clarity

In the end, the study underscores just how little is known about these complex overlaps — and the urgent need for more research.

“Our review shows that many cases fall through the cracks,” said Dr. Nyrenius. “We need better diagnostic methods and clinical trials to truly understand and treat this co-occurrence.”

Until then, the researchers warn, many patients may remain “between” three diagnoses — and without the right help.

Text by Anna Spyrou, Communications Officer

Download article:

Nyrenius, J., Zander, E., Ghaziuddin, M. et al. Co-occurrence of Autism, Psychosis and Catatonia: A Scoping Review. J Autism Dev Disord (2025). https://doi.org/10.1007/s10803-025-07086-2