Psychiatric comorbidity found to increase risk for schizophrenia in young patients with ADHD

The presence of psychiatric comorbidity in young patients with attention-deficit/hyperactivity disorder (ADHD) is associated with a higher risk for being diagnosed with schizophrenia, according to a study published online Nov. 30 in JAMA Network Open.

Soo Min Jeon, Pharm.D., Ph.D., from Jeju National University in South Korea, and colleagues assessed the risk for being diagnosed with schizophrenia among children and adolescents with ADHD. The analysis included 211,705 children and adolescents (ages 5 to 19 years) who received an ADHD diagnosis in 2010 through 2018.

The researchers found that patients with psychiatric comorbidity had a significantly higher risk for being diagnosed with schizophrenia than those without (adjusted hazard ratio, 2.14) in a dose-response manner. Several individual psychiatric disorders were associated with incident schizophrenia, including autism spectrum disorder, intellectual disability, tic disorder, depression, and bipolar disorder. Three-fourths of patients (73.8 percent) without psychiatric comorbidities experienced the emergence of other psychiatric disorders before developing schizophrenia.

"These findings highlighted the significance of carefully monitoring psychiatric comorbidities in patients with ADHD to effectively mitigate the burden of schizophrenia," the authors write.