Youth ADHD is associated with elevated risks of subsequent psychotic disorder

What relationship, if any, might there be between childhood ADHD and subsequent psychotic disorders? Previous epidemiological studies have produced conflicting results.

A French team of physicians conducted a systematic search of the peer-reviewed literature to conduct a meta-analysis to examine this question in greater depth.
They pooled twelve studies with a combined total of 1.85 million participants, consisting of 124,095 with ADHD and just over 1.72 million controls.

The psychotic disorders analyzed included schizophrenia, schizophreniform disorder, schizotypal personality disorder, schizoaffective disorder, delusional disorder, brief psychotic disorder, and psychotic disorder not otherwise specified. These disorders had to be diagnosed after the diagnosis of ADHD in children and adolescents under 18 years old.

The meta-analysis found that persons diagnosed in childhood or adolescence with ADHD were well over four times more likely to have subsequent diagnoses of psychotic disorders than those without a diagnosis of ADHD. Limiting the meta-analysis to the six studies that were adjusted for confounders produced an identical result.

There were no statistically significant between-group differences for subgroup analyses comparing psychotic disorder or schizophrenia outcomes, cohort or case-control study design, and adjusted or unadjusted estimates. There were no significant differences between males and females.

Heterogeneity among studies was moderate (43%), and there was no sign of publication bias. Removing one study reduced heterogeneity to low levels (18%), while very slightly raising the odds of subsequent diagnosis of psychotic disorder. Looking only at the more restrictive diagnosis of schizophrenia also made no difference in the odds.

No matter how the data were analyzed, in all instances, the odds of subsequent diagnosis of psychotic disorder rose well over fourfold for those diagnosed with ADHD in their youth.

The authors concluded, “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 P [psychotic disorders] develop. Such studies should consider the use of psychostimulants and the role of SUD [substance use disorder] in the causal path between ADHD and PD.”

MikaïlNourredine, Adrien Gering, Pierre Fourneret, BenjaminRolland, Bruno Falissard, Michel Cucherat, Marie-Maude Geoffray, Lucie Jurek, “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),