Other Disorders Associated with ADHD

A number of disorders may mimic or accompany attention-deficit disorder. ADHD exists alone in only about one-third of children. Many professionals object to the use of the single term “attention-deficit hyperactivity disorder” to encompass such a wide spectrum of behaviors, which they believe should be categorized into subgroups. Many of these problems require other modes of treatment and should be diagnosed separately, even if they accompany ADHD.

Attention-Deficit Disorder without Hyperactivity

Attention-deficit disorder can appear without hyperactivity, in which case the child's primary symptoms are distractibility and an inability to persist in tasks.

Oppositional-Defiant Disorder

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About 35% of children diagnosed with ADHD also have oppositional-defiant disorder (ODD). The most common symptom for this disorder is a pattern of negative, defiant, and hostile behavior toward authority figures that lasts more than 6 months. In addition to displaying inattentive and impulsive behavior, these children demonstrate aggression, have frequent temper tantrums, and display antisocial behavior. Up to 25% of children with ODD have phobias and other anxiety disorders, which should be treated separately.

Conduct Disorder

Some children with ADHD also have conduct disorder, which describes a complex group of behavioral and emotional disturbances seen in children. It includes aggression towards people and animals, destruction of property, deceitfulness, lying, or stealing, and general violation of rules.

Pervasive Developmental Disorder

Pervasive developmental disorder (PDD) is rare and usually marked by autistic-type behavior, hand-flapping, repetitive statements, slow social development, and speech and motor problems. If a child who has been diagnosed with ADHD does not respond to treatment, the parents might inquire about PDD, which often responds to antidepressants. Preliminary research also suggests that children with PDD may benefit from stimulants such as methylphenidate (Ritalin, Concerta). A 2005 study reported that methylphenidate worked better than placebo in treating hyperactivity in children with PDD. However, these children did not respond as well to methylphenidate as children with ADHD. The drug also caused side effects in many of the children with PDD.