Children and adolescents with attention-deficit/hyperactivity disorder (ADHD) may have an increased risk of a subsequent psychotic disorder (PD), according to a meta-analysis recently published online in JAMA Psychiatry.
The study included 12 cohort and case-control studies that examined the relative risk of developing a psychotic disorder in people aged less than 18 years who were diagnosed with ADHD, totaling 1.85 million participants. Within the cohort studies, a psychotic disorder caused by another medical condition and mood disorders with psychotic features were not considered among the main outcomes.
"To our knowledge, this is the first meta-analysis of observational studies assessing the association between an ADHD diagnosis and a subsequent diagnosis of PD," researchers wrote. "Given that PDs have a major functional effect, early detection and appropriate management are essential to improve the prognosis of children diagnosed with ADHD."
Patients need to follow-up with clinicians for treatment even after 18 years of age, researchers said.
Researchers found no significant differences between the analyzed groups according to psychotic disorder, schizophrenia outcomes, cohort or case-control study design, and adjusted or unadjusted estimates. The association remained high for the more restrictive diagnosis of schizophrenia. Sex as a covariate in the meta-regression did not alter the assessed association, according to the study.
There were several possible causations for the relationship between ADHD and subsequent PD that researchers explored, but further studies are needed. Some of the analyzed studies suggested prenatal factors such as diabetes, increased impulsivity leading to substance use disorder, and misdiagnosis of childhood ADHD.
"To improve our knowledge, further cohort studies should be conducted. Ideally, these studies would ensure a sufficiently long follow-up to account for the mean age at which PDs develop,” researchers wrote. “Such studies should consider the use of psychostimulants and the role of SUD in the causal path between ADHD and PD."
Nourredine M, Gering A, Fourneret P, et al. Association of attention-deficit/hyperactivity disorder in childhood and adolescence with the risk of subsequent psychotic disorder: a systematic review and meta-analysis. JAMA Psychiatry. 2021 February 24;[Epub ahead of print].