This study looked at 231 Dutch adults aged 60 to 94 from the Longitudinal Aging Study Amsterdam. People with low MMSE scores, cognitive decline, or a past stroke were left out. A small group met the study's ADHD criteria (23 people, 10%). Depressive symptoms were tracked over six years and anxiety symptoms over three.
Older adults with ADHD reported more depressive and anxiety symptoms than those without it. The authors call the gap a medium effect for depression and for anxiety. Many in the ADHD group reported clinically relevant depressive symptoms (43.5%). Among the others, the share was much lower (16.8%).
These links showed up at one point in time and across the years studied. People with more ADHD symptoms had depressive symptoms that rose over six years, while those with fewer stayed stable. Still, the course over time for people with an ADHD diagnosis did not differ from those without one. The authors conclude that the link seems to remain with aging.
The ADHD criteria were built for children and have not been validated in older adults. Other psychiatric disorders were not checked, so some cases may have been misdiagnosed. ADHD was also diagnosed after the symptoms were measured, so the study cannot show cause.
The authors suggest that when older adults report depressive and anxiety symptoms, clinicians should be alert for possible comorbid ADHD.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Michielsen, 2013: gap in depressive symptoms between older adults with and without ADHD, d = 0.68.
- Michielsen, 2013: gap in anxiety symptoms, d = 0.60.
What the terms mean:
- d is an effect size. Roughly, 0.2 is small, 0.5 is moderate and 0.8 is large. A minus sign shows the direction of the change, not its size.
Source: Michielsen M, Comijs H, Semeijn E, et al.. The comorbidity of anxiety and depressive symptoms in older adults with attention-deficit/hyperactivity disorder: A longitudinal study. Journal of Affective Disorders (2013). doi:10.1016/j.jad.2012.11.063