Attention Deficit Hyperactivity Disorder is the most common childhood psychiatric disorder and the second most prevalent adult psychiatric disorder second to Major Depression. Yet, until recently, ADHD in adults over age 50 was not identified. As we have come to understand, ADHD symptoms with impairments persist into adulthood for 60% of ADHD children.
For those adults with ADHD, how many will have symptoms that persist for the rest of their lives? How do these symptoms and impairments present? How do we discern ADHD symptoms from other factors contributing to cognitive change with age? How do we obtain clinical history in those patients who can’t remember childhood or adolescent symptoms? Would objective tests differentiate diagnoses? What treatments work well for this age group? What medical considerations are necessary for prescribing ADHD treatments to those with medical illness and multiple medications? What safety parameters need to be considered in this age group when prescribing ADHD medications? What are the drug-drug interactions that may be clinically relevant?
For clinicians and researchers, these questions represent opportunities to expand our fund of knowledge to better serve the needs of ADHD patients in all age categories.
The population of persons older than 65 years of age in the U.S. will grow from 43.1 million to 88.5 million between 2012 and 2050. A recent review of the literature on ADHD in older adults reports a prevalence rate of 2.8% in the Netherlands, 3.5% in Sweden, and 3.5% in Germany. A meta-analysis of ADHD prevalence in studies utilizing different age ranges spanning 18-78 years suggests that prevalence may decline with age. However, given that these studies used DSM-IV criteria with a symptom age threshold of 7 and the absence of a validated ADHD symptom profile for older adults, these cited prevalences may underestimate the ADHD population.
Reliance on childhood ADHD diagnosis to substantiate ADHD in older adults is often not useful because in the National Comorbidity Survey Replication in the U.S., 75% of ADHD adults ages 18-44 had not been diagnosed as children and no ADHD adults ages 60-77 were diagnosed as children. Remember that these people grew up in the 1950s and 1960s when ADHD was rarely identified and then only in the most hyperactive/impulsive and disruptive males.
I believe that ADHD in older adults will become the next clinical frontier. While there is some research beginning to accumulate to support identifying and treating this population, the relative absence of trained ADHD clinicians for this population means many unidentified older adults will be diagnosed inaccurately with age related cognitive disorders. To exemplify this likelihood, a U.S. study canvassing memory clinics demonstrated that only 1 in 5 clinics currently screen for ADHD. Therefore, older adults with ADHD are not identified and offered effective ADHD medication and treatment. The result may be ineffective treatment, unnecessary increased medical costs, and the decline in quality of life.
For those of you reading this blog, I would encourage you to consider ADHD in older adults whose cognitive complaints have been long-standing, whose negative consequences and impairments echo an ADHD life course, and in whom a first degree relative has ADHD.