Psychostimulant treatment and the developing cortex

In ADHD, ADHD child/adolescent, ADHD stimulant treatment, Medication, Psychiatry, Psychopharmacology on Wednesday, 3 October 2012 at 06:19

a brief report on stimulant treatment in children and adolescents.  2008 publication but still useful information.

Psychostimulant Treatment and the Developing Cortex in Attention Deficit Hyperactivity Disorder

Shaw P, Sharp WS, Morrison M, et al
Am J Psychiatry. 2008 Sep 15.


This study examined whether stimulants for attention-deficit/hyperactivity disorder (ADHD) were associated with differences in cerebral cortex development.

Study Design: Neuroanatomic MRI was used to assess the change in cortical thickness in 43 youths with ADHD; mean age at the first scan was 12.5 years, mean age at the second scan was 16.4 years. Of the 43 adolescents, 24 were treated with stimulants between scans while 19 were not treated between scans. Investigators included an additional comparison to a large sample of (n=294) of typically developing control youths.

Results: The rate of change of the cortical thickness in the right motor strip, the left middle/inferior frontal gyrus, and the right parieto-occipital region was different between the adolescents taking stimulants as compared with those not taking stimulants. Specifically, the study found more rapid cortical thinning in the group of patients not taking stimulants (mean cortical thinning of 0.16 mm/year [SD=0.17], compared with 0.03 mm/year [SD=0.11] in the group taking stimulants). Furthermore, comparison against the controls without ADHD showed that cortical thinning in the group not taking stimulants was in excess of age-appropriate rates.

Conclusion: These findings show no evidence that stimulant treatment is associated with slowing of overall growth of the cortical mantle.

Commentary: This is a remarkable paper from the Child Psychiatry Branch, National Institute of Mental Health, Bethesda, Maryland, and the Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada. The authors suggest that psychostimulant-induced improvements in cognition and action might foster cortical development within the normative range, as an example of activity-dependent neuroplasticity. The authors note that a randomized trial would be a better scientific design, but in the interim, this study shows the importance of comparisons with controls/normative data.


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