It was earlier thought that most children or adolescents with attention deficit hyperactivity disorder (ADHD) grow out of the condition as they get older. But according to a new study, it is not so simple.
Structural and functional deficits associated with abnormal working memory function were observed in young adults who were diagnosed with ADHD during their adolescent stage. This is suggestive that changes in the brain may persist into adulthood despite clinical improvement.
"[ADHD] was initially thought to abate in adolescence but increasing evidence indicates that ADHD frequently persists through to adulthood. Of those diagnosed during childhood, about 30-60% show symptoms during adulthood. It is because of its associated morbidity and disability across the lifespan that ADHD has come to be a major clinical and public health concern," Andres Roman-Urrestarazu, PhD, of the University of Cambridge, and colleagues wrote.
Researchers assessed brain scans of 49 young adults diagnosed with ADHD during adolescence and 34 controls in a voxel-based analysis, to determine if individuals with ADHD in adolescence had residual brain abnormalities in adulthood.
The participants in the study were in the age group of 20-24 years. One patient had received medication for ADHD. A sub-sample of 21 individuals with ADHD and 23 controls performed a working memory task while acquiring functional MRI data.
Lower grey matter volume in the caudate and poorer working memory, associated with failure to exhibit normal load-dependent caudate activation is observed in individuals with adolescent ADHD.
"Although people diagnosed with ADHD in adolescence may recover clinically sufficiently to no longer meet diagnostic criteria, they may continue to manifest abnormalities in caudate structure and function and working memory performance in early adulthood," Roman-Urrestarazu and colleagues wrote. "The results emphasize the importance of taking a wider perspective on ADHD outcomes than simply whether or not a particular patient meets diagnostic criteria at any given point in time."