A recent Dutch neuroimaging study has indicated that changes to white matter microstructure in the brain may be related to hyperactive/impulsive symptom improvements in adolescents with ADHD over time.
Magnetic resonance imaging (MRI) was used to investigate whether developmental improvements in ADHD symptoms with age are associated with underlying changes to white matter microstructure.
A large cohort of adolescents* was followed longitudinally over 6 years.
At baseline, ADHD symptoms† were assessed in 101 children with ADHD and 40 without ADHD (mean age 11.9 years), and approximately 75% completed follow-up. At follow-up, whole brain diffusion tensor imaging was used to measure fractional anisotropy (FA) and mean diffusivity (MD) indices of white matter microstructure, and a dimensional analysis related FA/MD to changes in ADHD symptoms over time.
Researchers found that developmental improvement (remission) in hyperactive/impulsive symptoms were significantly associated with changes in white matter microstructure (lower FA and higher MD values) in the left corticospinal tract. Changes in inattention symptoms over time were minimal and not associated with changes in FA or MD values.
Notably, MRI analysis was only conducted at follow-up, therefore obscuring the status of white matter microstructure at baseline. Nevertheless, the researchers concluded that as the corticospinal tract has an important role in the motor system, this may play a part in the persistence of hyperactivity/attention symptoms.
Read more about white matter changes in adolescents with ADHD here
*Part of the International Multicenter ADHD Genetics study
†Conners’ questionnaires and semi-structured, investigator-based interviews
Francx W, Zwiers MP, Mennes M, et al. White matter microstructure and developmental improvement of hyperactive/impulsive symptoms in attention-deficit/hyperactivity disorder. J Child Psychol Psychiatry 2015; 56: 1289-1297.