1. Effects of methylphenidate in auditory processing evaluation of children and adolescents with attention deficit hyperactivity disorder]

Cavadas M, Pereira LD, Mattos P.
Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rua Domingos Mondim 165, 21920-160 Rio de Janeiro, RJ, Brazil. marciacavadas@superig.com.br

Arq. Neuropsiquiatr. 2007 Mar; 65(1):138-43.

PURPOSE: To compare the performance of a group of children and adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) pre and post-methylphenidate use in a behavioral auditory processing test battery (AP).

METHOD: Twenty-nine subjects, male and female, ranging from 7 to 15 years old have undergone different behavioral auditory processing tests. A control group composed of 29 subjects with and without learning disabilities was also evaluated.

RESULTS: The group with ADHD had a performance similar to the control group without learning disabilities which improved after medication. The group with learning disabilities and without ADHD had the worst performance in tests while the group without learning disabilities and without ADHD exhibited the best ones.

CONCLUSION: The AP battery was unable to distinguish ADHD patients from paired controls; the use of methylphenidate improved the performance on AP tests of ADHD group in the post-medication evaluation.

2. Investigation of parent-of-origin effects in ADHD candidate genes.

Kim JW, Waldman ID, Faraone SV, Biederman J, Doyle AE, Purcell S, Arbeitman L, Fagerness J, Sklar P, Smoller JW.

Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.

Am J Med Genet B Neuropsychiatr Genet. 2007 Apr 10; [Epub ahead of print]

Attention deficit hyperactivity disorder (ADHD) is a common early-onset childhood disorder with a strong genetic component. Results from previous studies have suggested that there may be a parent-of-origin effect for ADHD candidate genes. In particular, a recent investigation identified a pattern of paternal over-transmission of risk alleles for nine ADHD candidate genes. We examined this phenomenon in a sample of 291 trios for five genes previously associated with ADHD (HTR1B, SNAP-25, DRD5, DAT1, and BDNF). Using a dense map of markers and two analytic methods in this relatively large family-based sample, we do not find any evidence for significant paternal over-transmission of risk alleles in these candidate loci. Thus, we conclude that a substantial parent-of-origin effect is unlikely for these leading ADHD candidate genes. (c) 2007 Wiley-Liss, Inc.

3. Review of long-acting stimulants in the treatment of attention deficit hyperactivity disorder.

Weisler RH.

Duke University Medical Center, Durham, NC, USA. rweisler@aol.com

Expert Opin Pharmacother. 2007 Apr; 8(6):745-58.

A number of long-acting medications for the treatment of attention deficit hyperactivity disorder (ADHD) have recently been developed and approved for use in the US. These compounds are intended to optimize and maintain ADHD symptom control throughout the day, while eliminating problems associated with short-acting medications, such as the need for in-school, midday or multiple daily doses. Recent reports confirm that the safety and tolerability of long-acting medications are similar to those of short-acting medications, although long-acting medications appear to have a lower risk of abuse and diversion and may be associated with significant improvements in medication adherence. Distinctions can be made among the long-acting medications with regard to the onset, magnitude and duration of their clinical effects. Recognition of these differences is important for individualizing treatment for patients with ADHD.

4. Targeting the dopamine system in the treatment of attention-deficit/hyperactivity disorder.

Staller JA, Faraone SV.

Division of Child & Adolescent Psychiatry, SUNY Upstate Medical University, Syracuse, NY 13210, USA. stallerj@upstate.edu

Expert Rev Neurother. 2007 Apr; 7(4):351-62.

Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable condition that affects a significant number of children and adults worldwide. During the past 30 years, the diagnosis and treatment of ADHD has relied on clinical assessment and empirical experience with stimulant medications. More recently, advances in family genetic studies, molecular genetic studies, preclinical research, radiographic imaging techniques and neuropsychological evaluation have significantly enhanced our understanding of the neurobiology of ADHD. This review highlights the current central role of dopamine in the pathophysiology and treatment of ADHD and implications for future advances in diagnosis and treatment.

5. The neuropsychiatry of impulsivity.

Chamberlain SR, Sahakian BJ.

Department of Psychiatry, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge, UK Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.

Curr Opin Psychiatry. 2007 May; 20(3):255-261.

PURPOSE OF REVIEW: Impulsive symptoms occur across neuropsychiatric disorders, with important ramifications for everyday functioning and quality of life. This article considers recent developments in the neuropsychological assessment of impulsivity with a focus on the ability to suppress motor responses (response inhibition).

RECENT FINDINGS: Using objective tests, response inhibition deficits were identified in several neuropsychiatric conditions associated with impulsivity, namely attention deficit hyperactivity disorder, trichotillomania, obsessive-compulsive disorder, and chronic substance abuse. Deficits were also found in unaffected first-degree relatives of attention deficit hyperactivity disorder and obsessive-compulsive disorder patients. Evidence from patients with focal brain lesions and from healthy volunteers using functional MRI and transcranial stimulation implicated the right inferior frontal gyrus in response inhibition. Pharmacological manipulations of the serotonin system had no detectable behavioural effects on response inhibition, whereas manipulations of the noradrenaline system did.

SUMMARY: Neuropsychological assessment shows great promise in the investigation of impulsivity and its brain substrates. These results support a key role for response inhibition, a function linked to the right inferior frontal gyrus, in the manifestation of impulsivity. Measures of response inhibition will contribute to the search for psychiatric endophenotypes, novel treatments, and more optimal diagnostic classification systems for neuropsychiatric disorders.