Psychiatric comorbidity in children and adolescents with restless legs syndrome: a retrospective study

Children and adolescents with restless legs syndrome (RLS) are commonly diagnosed with comorbid attention deficit hyperactivity disorder and behavioral disturbances. Uncertainty exists over the significance of other co-occurring psychiatric disorders and their pharmacologic management in children with RLS. The purpose of this study was to determine the prevalence and nature of psychiatric disorders in children with RLS and to describe the use of psychotropic medications in our study cohort.

The electronic medical records of children younger than 18 years of age who had been diagnosed with RLS between January 1, 2003, and December 31, 2009, were reviewed. Only those patients whose findings were consistent with the 2003 NIH workshop diagnostic criteria for probable or definite restless legs syndrome were included in this study. The medical records were cross-referenced for encounters with a child psychiatrist or psychologist. Likewise, only psychiatric diagnoses whose medical records explicitly reflected DSM-IV diagnostic criteria for psychiatric disorder(s) were included. Demographic data, serum ferritin, psychotropic medications, and in some cases, the results of pharmacogenomic testing were included in the data analysis in an ad hoc fashion.

We found 374/922 patients who met diagnostic criteria for childhood onset RLS. The mean age of the subjects was 10.6 years (range 0 to 18) and the male to female ratio was approximately 1:1. Overall, 239/374 (64%) patients with RLS had one or more comorbid psychiatric disorders. Attention deficit hyperactivity disorder was found in 94/374 (25%) patients, mood disturbances were found in 109/374 (29.1%) patients, anxiety disorders in 43/374 (11.5%) patients, and behavioral disturbances in 40/374 (10.9%) patients. Attention deficit hyperactivity disorder and disruptive behavior disorders were more common in males (OR = 1.94 for both), whereas mood disturbances and anxiety disorders were more common in females (OR = 1.6 and 1.26, respectively). Mean serum ferritin levels derived from all patients without any psychiatric disorder were compared to all patients with one or more psychiatric disorder. No differences were found. The number of new psychotropic medication trials increased significantly with increase in patient age. Stimulants and antidepressant medications were the most commonly prescribed agents. As a part of clinical care, 15 of these patients underwent pharmacogenomic testing. Metabolic abnormalities were predicted by genotyping in 12/15 (80%) patients.

Comorbid psychiatric conditions occurred in two-thirds of children with RLS, underscoring the need for multidisciplinary management of this condition. An important relationship might exist between psychotropic medication, and possibly pharmacogenomic factors, in children and adolescents with symptoms of restless legs syndrome. These findings are consistent and build on those reported in the adult literature.