Difference between ADHD and Mania in Children(Source)

The incidence of ADHD in children who are later diagnosed in adulthood with bipolar disorder (BD) is indeed quite high. Compounding this situation is the high rate of co-occurrence of these 2 disorders. In some series, 93% of children with diagnosed BD have comorbid ADHD, whereas 59% of adolescents with adolescent-onset mania have ADHD. The association becomes less pronounced in adults with diagnosed mania, of whom only 10% have comorbid ADHD.

Symptoms common to both, especially in younger children, include hyperactivity, inattention, irritability, and rage, with the severity of these symptoms being more intense in children with BD. Overall impairment is more profound in individuals with both disorders, although environmental accommodations, including the provision of structure, help less to alleviate symptoms in BD than those ascribed to ADHD.

There are several other clinical distinctions that I use in my practice to differentiate ADHD from BD. A strong family history of bipolar disorder is highly supportive of that diagnosis in a particular child. Children with BD are often "mean" and hurtful in their style of social interaction, something not typically seen in ADHD. Children with bipolar disorder can be sexualized to a worrying extent, without any history of sexual abuse. Comments and actions might make adults in their environment feel uncomfortable. Grandiose statements regarding their strengths and abilities might also be a tip-off to BD.

Although in young children the diagnosis relies heavily on clinical impression, supportive mania scales are also available and may be used to guide the diagnosis. These include the Young Mania Rating Scale (YMRS), the parent version of the YMRS, and the Child Behavior Checklist (CBCL).

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