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Articles by K. J Plessen
Total Records ( 2 ) for K. J Plessen
  B. S Peterson , M. N Potenza , Z Wang , H Zhu , A Martin , R Marsh , K. J Plessen and S. Yu
 

OBJECTIVE: The authors examined the effect of psychostimulants on brain activity in children and adolescents with ADHD performing the Stroop Color and Word Test. METHOD: The authors acquired 52 functional MRI scans in 16 youths with ADHD who were known responders to stimulant medication and 20 healthy comparison youths. Participants with ADHD were scanned on and off medication in a counterbalanced design, and comparison subjects were scanned once without medication. RESULTS: Stimulant medication significantly improved suppression of default-mode activity in the ventral anterior cingulate cortex in the ADHD group. When off medication, youths with ADHD were unable to suppress default-mode activity to the same degree as comparison subjects, whereas when on medication, they suppressed this activity to comparison group levels. Greater activation of the lateral prefrontal cortex when off medication predicted a greater reduction in ADHD symptoms when on medication. Granger causality analyses demonstrated that activity in the lateral prefrontal and ventral anterior cingulate cortices mutually influenced one another but that the influence of the ventral anterior cingulate cortex on the lateral prefrontal cortex was significantly reduced in youths with ADHD off medication relative to comparison subjects and increased significantly to normal levels when ADHD youths were on medication. CONCLUSIONS: Psychostimulants in youths with ADHD improved suppression of default-mode activity in the ventral anterior cingulate and posterior cingulate cortices, components of a circuit in which activity has been shown to correlate with the degree of mind-wandering during attentional tasks. Stimulants seem to improve symptoms in youths with ADHD by normalizing activity within this circuit and improving its functional interactions with the lateral prefrontal cortex.

  D. A Gorman , N Thompson , K. J Plessen , M. M Robertson , J. F Leckman and B. S. Peterson
 

Background

Children with Tourette syndrome generally experience improvement of tics by age 18 years, but psychosocial and comorbidity outcomes at this age are unclear.

Aims

To compare psychosocial outcomes and lifetime comorbidity rates in older adolescents with Tourette syndrome and controls. We hypothesised a priori that individuals with Tourette syndrome would have lower Children’s Global Assessment Scale (CGAS) scores.

Method

A total of 65 individuals with Tourette syndrome, identified in childhood, and 65 matched community controls without tic or obsessive–compulsive disorder (OCD) symptoms were assessed around 18 years of age regarding psychosocial functioning and lifetime psychiatric disorders.

Results

Compared with controls, individuals with Tourette syndrome had substantially lower CGAS scores (P = 10–8) and higher rates of attention-deficit hyperactivity disorder (ADHD), major depression, learning disorder and conduct disorder (P≤0.01). In the participants with Tourette syndrome, poorer psychosocial outcomes were associated with greater ADHD, OCD and tic severity.

Conclusions

Clinically ascertained children with Tourette syndrome typically have impaired psychosocial functioning and high comorbidity rates in late adolescence.

 
 
 
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