A new long-term study has found that the majority of children who are diagnosed with attention-deficit hyperactivity disorder (ADHD) continue to have ADHD or another psychiatric disorder in adulthood. The research stresses that ADHD is a chronic disorder that warrants intense intervention after diagnosis to ward off potentially serious long-term consequences. The study was published online on March 4 in the journal Pediatrics by researchers affiliated with Harvard Medical School (Boston, Massachusetts), the Mayo Clinic (Rochester, Minnesota), and Baylor College of Medicine (Houston, Texas).
ADHD is the most commonly diagnosed behavioral disorder of childhood, affecting an estimated 3-5% of school aged children. It is diagnosed much more often in boys than in girls. The researchers examined long-term outcomes of ADHD in a population-based sample of childhood ADHD cases and controls. The study group comprised 5,718 adults with childhood ADHD and non-ADHD controls from the same birth cohort (similar backgrounds). The subjects were enrolled in a prospective (forward-looking) outcome study as children and followed for 20 years into adulthood. The researchers constructed standardized mortality ratios (SMRs) to compare overall and cause-specific mortality between childhood ADHD cases and controls. Incarceration status (prison term) was determined for childhood ADHD cases. A standardized neuropsychiatric interview was administered.
After the follow-up period, vital status for 367 childhood ADHD cases was determined: seven (1.9%) were deceased and 10 (2.7%) were currently incarcerated. The SMR for overall survival of childhood ADHD cases versus controls was 1.88; for accidents it was 1.70. However, the cause-specific mortality for suicide only was significantly higher among ADHD cases (SMR: 4.83). Among the childhood ADHD cases participating in the prospective assessment (232 subjects with an average age of 27.0 years), ADHD persisted into adulthood for 29.3%. Participating childhood ADHD cases were more likely than controls (335 subjects with an average age of 28.6 years) to have one or more other psychiatric disorder (56.9% vs. 34.9%).
The authors concluded that childhood ADHD is a chronic health problem, with significant risk for mortality, persistence of ADHD, and long-term morbidity in adulthood.
In recent years, the rates of diagnosis and medication use have soared both in childhood and in adulthood; this has prompted some healthcare officials to theorize whether the condition is overdiagnosed. In the United States, the rate of diagnosis has increased by an average of 3% per year between 1997 and 2006, according to the Centers for Disease Control and Prevention (CDC).
The study authors note that previous studies evaluating the persistence of ADHD over time had found that the rates of those who still had the condition in adulthood ranged substantially, from 6% to more than 60%; however, these were smaller studies than the current one and focused on individuals who were in psychiatric care. The authors cautioned that their findings from this study of middle-class, Caucasian children may not be applicable nationwide; however, outcomes among children who have less access to medical and educational resources are, if anything, likely to be worse than in the sample.
To be diagnosed with ADHD, children should have at least six attention symptoms or six activity and impulsivity symptoms; these symptoms should exceed what would be expected for children their age. The symptoms must be present for at least six months, observable in two or more settings, and not caused by another problem. The symptoms must be severe enough to cause significant difficulties. Some symptoms must be present before age seven.
Older children have ADHD in partial remission when they still have symptoms but no longer meet the full definition of the disorder. Some children with ADHD primarily have the Inattentive Type, some the Hyperactive-Impulsive Type, and some the Combined Type. Those with the Inattentive type are less disruptive and are easier to miss being diagnosed with ADHD.
- Fails to give close attention to details or makes careless mistakes in schoolwork
- Difficulty sustaining attention in tasks or play
- Does not seem to listen when spoken to directly
- Does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace
- Difficulty organizing tasks and activities
- Avoids or dislikes tasks that require sustained mental effort (such as schoolwork)
- Often loses toys, assignments, pencils, books, or tools needed for tasks or activities
- Easily distracted
- Often forgetful in daily activities
- Fidgets with hands or feet or squirms in seat
- Leaves seat when remaining seated is expected
- Runs about or climbs in inappropriate situations
- Difficulty playing quietly
- Often "on the go," acts as if "driven by a motor," talks excessively
- Impulsivity symptoms:
- Blurts out answers before questions have been completed
- Difficulty awaiting turn
- Interrupts or intrudes on others (butts into conversations or games)