Pharmacological Treatment of Attention-Deficit/HyperactivityDisorder

The effects of methylphenidate on prepulse inhibition during attended and ignored prestimuli among boys with attention-deficit hyperactivity disorder

“…The robust effect of methylphenidate in the present study supports the hypothesis that improvement in ADHD often occurs with relatively low doses of methylphenidate and that higher doses yield diminishing returns (Smith et al 1998;Evans et al 2001;c.f., Rapport and Kelly 1991;Schachar and Ickowicz 1999). However, it is important to point out that all ADHD participants in the present study had prior experience with methylphenidate.…”

“…Methylphenidate blocks the re-uptake of both dopamine and norepinephrine, and both neurotransmitters appear important in the therapeutic effect of the drug (Castellanos 1999;Schachar and Ickowicz 1999;Mehta et al 2001;Pliszka 2001). For example, recent imaging work in adults without ADHD indicated that 0.25 mg/kg oral methylphenidate blocks more that 50% of dopamine transporter in the striatum (Volkow et al 1998), significantly increasing striatal dopamine (Volkow et al 2001).…”

“…Methylphenidate is the most frequently prescribed medication for ADHD (Goldman et al 1998), and it improves both behavioral and cognitive aspects of the disorder at doses between 0.3 mg/kg and 1.0 mg/kg (Schachar and Ickowicz 1999). Methylphenidate prevents re-uptake of dopamine and norepinephrine, and both actions are believed to be important in the drug's efficacy (Castellanos 1999;Schachar and Ickowicz 1999;Mehta et al 2001). From a clinical perspective, methylphenidate would be expected to increase children's focus on attended tones during the discrimination task, enhancing prepulse inhibition during attended, but not ignored, prestimuli.…”

Once-Daily Multilayer-Release Methylphenidate in a Double-Blind, Crossover Comparison to Immediate-Release Methylphenidate in Children with Attention-Deficit/Hyperactivity Disorder

“…Methylphenidate (MPH) is the psychostimulant used most frequently in the treatment of ADHD and results in significant improvement in 70-80% of affected children (Schachar and Ickowicz 1999). Immediate-release (IR) MPH is most often prescribed twice per day, although there is increasing appreciation of the need for symptom improvement during family social activities.…”