MedWire News: Children with attention-deficit hyperactivity disorder (ADHD) are at increased risk for developing bipolar disorder, suggest results from an Italian study.
"A major feature of juvenile bipolar disorder is its frequent 'atypicality,, compared with adult 'standards,' in terms of presentation, course, and pattern of comorbidity," write Gabriele Masi (Scientific Institute of Child Neurology and Psychiatry, Calambrone, Pisa) and team in the journal Psychiatry Research.
They explain that a "marker of the earliest forms of bipolar disorder is the high comorbidity with disruptive behavior disorders, namely ADHD," but add that "the rate of this comorbidity is still debated in the literature."
To investigate further, and to identify predictors of bipolar disorder in children with ADHD, the team studied 173 young people (156 boys and 17 girls) with the behavioral disorder, who were aged 6-17 years, and 100 age- and gender-matched children who did not have a previous mental health diagnosis (controls).
All of the children were assessed for bipolar disorder by an experienced child psychiatrist using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL).
The researchers found that 29 (16.7%) of the children with ADHD also met criteria for bipolar disorder compared with just one of the controls.
Among the 29 children with ADHD plus bipolar disorder, 16 (55.2%) had bipolar disorder not otherwise specified and 11 (37.9%) had ultra-rapid cycling bipolar disorder.
The most common form of ADHD among children who also had bipolar disorder was the combined subtype (72.4%), followed by the hyperactive-impulsive subtype (24.1%), with just 3.5% having the inattentive subtype.
Children with ADHD plus bipolar disorder had higher total scores on the ADHD-Rating Scale (ADHD-RS), at a mean of 41.64 versus 37.21, as well as higher scores on the ADHD-RS hyperactivity subscale, at a mean of 21.2 versus 18.2, compared with those with ADHD alone.
Children with ADHD plus bipolar disorder also had significantly higher rates of major depression (24.0% versus 7.0%), oppositional defiant disorder (86.2% versus 42.6%), and conduct disorder (34.5% versus 14%) than those with ADHD alone.
Masi and team conclude: "Our data confirm that ADHD children present a higher rate of bipolar disorder compared with a control school sample."
They add: "The identification of clinical features with an increased risk of BD can improve diagnosis, prognosis, and treatments."
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