ADHD and psychosis link is more complex than a simple risk label, review finds

A review in Molecular Psychiatry says shared biology, early symptoms, treatment effects and life stressors may all help explain the overlap between ADHD and psychotic disorders.

A new review in Molecular Psychiatry argues that the relationship between attention deficit hyperactivity disorder and psychotic disorders is more complex than a simple risk label, with several possible explanations ranging from shared biology to the effects of treatment and the knock-on impact of life experiences linked to ADHD. The paper says clinicians should treat ADHD seriously even when psychosis is a concern, while paying closer attention to those with additional risk factors such as a personal or family history of psychosis.

The review was based on a PubMed search covering studies published from January 1, 2020, to June 6, 2026. After screening more than 2,300 records, the authors retained 26 papers judged to have the strongest relevance and evidence quality. Their aim was not to settle the question with a single answer, but to weigh competing explanations for why ADHD and psychotic disorders so often appear together.

One possibility is that some childhood ADHD diagnoses in people who later develop psychosis may actually reflect very early signs of an emerging psychotic illness rather than true ADHD. The authors note that longitudinal studies have found childhood developmental difficulties, including attention, language, motor and social problems, before later psychotic illness, especially when onset is early. A 2021 systematic review and meta-analysis in JAMA Psychiatry found that childhood ADHD was associated with a markedly higher risk of later psychotic disorder, underscoring the need for follow-up beyond adolescence.

Another question is whether ADHD treatment itself changes psychosis risk. The review says older concerns about stimulants have not been strongly supported by registry data, particularly for methylphenidate, which has not shown a clear rise in psychosis risk in large observational studies. By contrast, some studies have suggested a higher risk with prescription amphetamines, especially at higher doses. A separate systematic review on therapeutic stimulant use found no clear signal for methylphenidate, but it did flag amphetamines as a possible concern. The authors of the new review therefore recommend caution, careful monitoring and, where risk is elevated, a preference for methylphenidate over amphetamines.

The paper also points to indirect pathways that may matter in real-world care. ADHD can increase exposure to substance misuse, victimisation, maltreatment and other stressors that are themselves linked to psychosis. It may also travel with other psychiatric conditions, such as anxiety, depression and post-traumatic stress disorder, which could help identify people at greater risk. At the same time, the review stresses that undertreated ADHD carries its own harms, including poorer long-term mental health and social outcomes.

A further explanation is shared neurodevelopmental biology. The authors argue that ADHD, autism spectrum disorder and schizophrenia may overlap in their underlying developmental origins, partly through shared rare genetic variants, common genetic risk and prenatal or perinatal influences. They also highlight the clinical overlap seen in conditions such as 22q11.2 deletion syndrome, where ADHD is common and later psychotic outcomes are more frequent. A recent meta-analysis reported that ADHD is present in a substantial share of people with psychotic disorders, reinforcing the need to assess both conditions rather than assuming one diagnosis excludes the other.