Associations of MAOA-VNTR or 5HTT-LPR alleles with attention-deficit hyperactivity disorder symptoms are moderated by platelet monoamine oxidase B activity.

The monoamine systems have been suggested to play a role in the biological basis of attention-deficit hyperactivity disorder (ADHD) symptoms. Thus, polymorphisms, for example, in the monoamine oxidase A (MAOA) and the serotonin transporter (5HTT) genes have been associated with ADHD-like phenotypes. Furthermore, platelet monoamine oxidase B (MAOB) activity has frequently been linked to impulsiveness-related traits. In this study, we have studied ADHD symptoms with regard to the combination of platelet MAOB activity and MAOA-variable number of tandem repeats (VNTR) or 5HTT-LPR genotype. The study group consisted of 156 adolescent twin pairs, that is, 312 individuals, who participated in a previous study. ADHD symptoms were scored with a structured clinical interview of both the twins and a parent using Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version. The presence of a short 5HTT-LPR or short MAOA-VNTR allele, in combination with high levels of platelet MAOB enzyme activity was associated with higher scores of ADHD-like problems (P<0.001 and 0.01, respectively). This re-examination of ADHD scores in a nonclinical sample suggests that effects of MAOA-VNTR and 5HTT-LPR are moderated by platelet MAOB activity.

Psychiatric problems associated with subthreshold ADHD and disruptive behaviour diagnoses in teenagers.

AIM: To study the coexistence of subthreshold diagnoses of both attention deficit hyperactivity disorder (ADHD) and disruptive behaviour disorders (DBD) with other symptoms of child and adolescent psychiatric disorders as well as risk behaviours associated with smoking, alcohol and drug use. METHODS: A population-based sample of twins including 177 girls and 135 boys was interviewed using the Swedish version of Kiddie-SADS Present and Lifetime Version (K-SADS-PL). Subthreshold diagnoses were compiled based on the ADHD and DBD criteria, where each criterion was assessed as 'possible' or 'certain' according to K-SADS-PL. The odds ratios (OR) between the subthreshold diagnoses and each of the screening questions in K-SADS-PL were calculated. RESULTS: Subthreshold diagnoses of ADHD and DBD coexisted with the screening questions concerning depression, mania, panic attack, phobias, anorexia nervosa, motor tics and posttraumatic stress disorder (PTSD) in girls. In boys, these subthreshold diagnoses coexisted with symptoms of depression and PTSD. For both boys and girls, smoking and high alcohol consumption contributed to a high OR with regard to ADHD and DBD. CONCLUSION: Subthreshold diagnoses of ADHD and DBD were risk factors for several other psychiatric symptoms as well as smoking and high alcohol consumption. Thus, a broad clinical assessment is needed for adolescents with such preliminary diagnoses.

EPA supplementation improves teacher-rated behaviour and oppositional symptoms in children with ADHD.

AIM: Measure efficacy of eicosapentaenoic acid (EPA) in children with attention deficit hyperactivity disorder (ADHD). METHODS: Randomized controlled trial (RCT) of 0.5 g EPA or placebo (15 weeks) in 92 children (7-12 years) with ADHD. Efficacy measure was Conners' Parent/Teacher Rating Scales (CPRS/CTRS). Fatty acids were analysed in serum phospholipids and red blood cell membranes (RBC) at baseline and endpoint with gas chromatography. RESULTS: EPA improved CTRS inattention/cognitive subscale (p = 0.04), but not Conners' total score. In oppositional children (n = 48), CTRS total score improved ≥25% in 48% of the children receiving EPA vs. 9% for placebo [effect size (ES) 0.63, p = 0.01]. In less hyperactive/impulsive children (n = 44), ≥25% improvement was seen in 36% vs. 18% (ES 0.41, n.s.), and with both these types of symptoms 8/13 with EPA vs. 1/9 for placebo improved ≥25% (p = 0.03). Children responding to treatment had lower EPA concentrations (p = 0.02), higher AA/EPA (p = 0.005) and higher AA/DHA ratios (p = 0.03) in serum at baseline. Similarly, AA/EPA (p = 0.01), AA/DHA (p = 0.038) and total omega-6/omega-3 ratios (p = 0.028) were higher in RBC, probably because of higher AA (p = 0.011). CONCLUSION: Two ADHD subgroups (oppositional and less hyperactive/impulsive children) improved after 15-week EPA treatment. Increasing EPA and decreasing omega-6 fatty acid concentrations in phospholipids were related to clinical improvement.

ADHD and Disruptive Behavior scores - associations with MAO-A and 5-HTT genes and with platelet MAO-B activity in adolescents.

BACKGROUND: Pharmacological and genetic studies suggest the importance of the dopaminergic, serotonergic, and noradrenergic systems in the pathogenesis of Attention Deficit Hyperactivity Disorder (ADHD) and Disruptive Behavior Disorder (DBD). We have, in a population-based sample, studied associations between dimensions of the ADHD/DBD phenotype and Monoamine Oxidase B (MAO-B) activity in platelets and polymorphisms in two serotonergic genes: the Monoamine Oxidase A Variable Number of Tandem Repeats (MAO-A VNTR) and the 5-Hydroxytryptamine Transporter gene-Linked Polymorphic Region (5-HTT LPR). METHODS: A population-based sample of twins, with an average age of 16 years, was assessed for ADHD/DBD with a clinical interview; Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL). Blood was drawn from 247 subjects and analyzed for platelet MAO-B activity and polymorphisms in the MAO-A and 5-HTT genes. RESULTS: We found an association in girls between low platelet MAO-B activity and symptoms of Oppositional Defiant Disorder (ODD). In girls, there was also an association between the heterozygote long/short 5-HTT LPR genotype and symptoms of conduct disorder. Furthermore the heterozygote 5-HTT LPR genotype in boys was found to be associated with symptoms of Conduct Disorder (CD). In boys, hemizygosity for the short MAO-A VNTR allele was associated with disruptive behavior. CONCLUSION: Our study suggests that the serotonin system, in addition to the dopamine system, should be further investigated when studying genetic influences on the development of Disruptive Behavior Disorders.