Impact of restless legs syndrome and iron deficiency on attention-deficit/hyperactivity disorder in children.
OBJECTIVE
Increasing evidence suggests a significant comorbidity between attention-deficit/hyperactivity disorder (ADHD) and restless legs syndrome (RLS). Iron deficiency may underlie common pathophysiological mechanisms in subjects with ADHD plus RLS (ADHD+RLS). To date, the impact of iron deficiency, RLS and familial history of RLS on ADHD severity has been scarcely examined in children. These issues are addressed in the present study.


METHODS
Serum ferritin levels, familial history of RLS (diagnosed using National Institutes of Health (NIH) criteria) and previous iron supplementation in infancy were assessed in 12 ADHD+RLS children, 10 ADHD children and 10 controls. RLS was diagnosed using NIH-specific pediatric criteria, and ADHD severity was assessed using the Conners' Parent Rating scale.


RESULTS
ADHD symptom severity was higher, although not significantly, in children with ADHD+RLS compared to ADHD. The mean serum ferritin levels were significantly lower in children with ADHD than in the control group (p<0.0005). There was a trend for lower ferritin levels in ADHD+RLS subjects versus ADHD. Both a positive family history of RLS and previous iron supplementation in infancy were associated with more severe ADHD scores.


CONCLUSIONS
Children with ADHD and a positive family history of RLS appear to represent a subgroup particularly at risk for severe ADHD symptoms. Iron deficiency may contribute to the severity of symptoms. We suggest that clinicians consider assessing children with ADHD for RLS, a family history of RLS, and iron deficiency.
Konofal
Eric
E
Service de Psychopathologie de l'Enfant et de l'Adolescent, Hôpital Robert Debré, 48 boulevard Sérurier, 75019 Paris, France. eric.konofal@rdb.aphp.fr
Cortese
Samuele
S
Marchand
Martine
M
Mouren
Marie-Christine
MC
Arnulf
Isabelle
I
Lecendreux
Michel
M
D018798:Anemia, Iron-Deficiency / Q000150:complications* / Q000453:epidemiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D004298:Dopamine / Q000097:blood; D001330:Electronic Data Processing; D005260:Female; D005293:Ferritins / Q000097:blood; D006801:Humans; D008297:Male; D015995:Prevalence; D012148:Restless Legs Syndrome / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D012720:Severity of Illness Index
D005293:Ferritins; D004298:Dopamine