No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder.

BACKGROUND: The aim of the current study was to explore the role of aromatic amino acids (AAAs) in blood in relation to attention-deficit/hyperactivity disorder (ADHD). Given their impact on the synthesis of serotonin and dopamine, decreased concentrations of the AAAs tryptophan, tyrosine and phenylalanine in blood may contribute to the expression of ADHD symptoms. Decreased AAA blood concentrations, in turn, may be related to lowered dietary protein intake or to abnormal AAA catabolism, as evidenced by increased urinary AAA concentrations. METHODS: Eighty-three children with ADHD (75% males) and 72 typically developing (TD) children (51% males), aged 6 to 13 years, participated in the study. AAA concentrations were assessed in blood spots and an 18-hour urinary sample. A nutritional diary was filled out by parents to calculate dietary protein intake. Parent and teacher questionnaires assessed symptoms of ADHD, oppositional defiant disorder, conduct disorder, and autism spectrum disorder. RESULTS: Children with ADHD showed normal AAA concentrations in blood spots and urine, as well as normal protein intake compared to controls. No associations between AAA concentrations and symptoms of ADHD or comorbid psychiatric disorders were found. CONCLUSIONS: This study is the first to explore AAA metabolism in children with ADHD using a well-defined and relatively large sample. We found that AAA deficiencies are not related to ADHD. The results do not support treatment with AAA supplements in children with ADHD. Future studies regarding the cause of serotonin and dopamine alterations in ADHD should focus on other explanations, such as effects of altered transport of AAAs.

Mood and hormone responses to psychological challenge in adolescent males with conduct problems.

BACKGROUND: Relations between stress hormones and antisocial behavior are understudied. METHODS: A subsample (n = 335) of at-risk males recruited in first grade for a longitudinal study were recruited at approximately 16 years of age for a laboratory study, including two psychological challenges: describing their worst experience on videotape, and a task in which a loud tone could be avoided. Measures of affect, urine, and saliva were collected multiple times before and after challenges. RESULTS: Negative affect increased following the worst-event challenge and decreased following the avoidance challenge. Mean conduct problems (CP) across ages 7-17 years were positively related to negative affect and inversely related to positive affect. CP were inversely related to post-challenge urinary epinephrine (E) levels when baseline E and potential confounds were controlled. Cortisol concentrations in saliva collected soon after the first challenge were positively related to CP in a post hoc subset of youths with extreme CP. CONCLUSIONS: Key findings A) associated persistent CP with more negative affectivity and less positive affectivity, B) replicated and extended prior findings of an inverse association of CP and urinary E, and C) suggested provocative hypotheses for future study relating CP, trauma history, trauma recall, and cortisol reactivity.