Reduced serotonergic functioning changes heart rate in ADHD.
ABSTRACT Reduced mean heart rate (HR) was shown to be a biophysiological marker for aggression, which in turn was proven to be related to changed serotonergic neurotransmission. A total of 16 ADHD-diagnosed boys were subjected to rapid tryptophan depletion (RTD) and a placebo in a double-blind within-subject crossover-design. Mean HR was assessed under RTD/placebo. Low impulsive patients behaving aggressively under RTD showed a lowered HR under RTD versus placebo. Diminished 5-HT functioning was associated with lowered HR and aggressive behaviour.
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ABSTRACT: Early-onset bipolar disorder (BD) and attention-deficit-hyperactivity disorder (ADHD) have recently been the subject of highly controversial debate, due to theories regarding underlying pathophysiological processes and a clinical overlap of symptoms. Epidemiological data, clinical aspects neuroimaging, neurochemical, and genetic studies suggest that there may be a possible relationship between biological factors and clinical characteristics in the development of symptoms. However, longitudinal data supporting the hypothesis of a diagnostic shift from BD to ADHD symptoms and vice versa are currently not available. These would be essential to enable further investigations into whether these two disorders possibly represent two different aspects of an underlying common psychopathophysiological entity.Dialogues in clinical neuroscience 02/2009; 11(1):63-72.
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ABSTRACT: Research on 5-HT-functioning in adult patients and healthy subjects using rapid tryptophan depletion (RTD) has indicated weak but stable effects on mood ratings. Altered mood in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) can confound the differential diagnosis between severe ADHD and mood disorders such as pediatric bipolar disorder. The present study investigated the effects of RTD induced lowered central nervous 5-HT-levels on mood self-ratings in children with ADHD. Seventeen boys with ADHD participated in the study in a double-blind within-subject crossover-design. They were administered RTD within an amino acid drink lacking tryptophan, thus lowering central nervous 5-HT-synthesis. On another day they received a placebo. Self-rated mood was assessed on both days at baseline conditions and at three different post-drink time-points. RTD had no clear effect on mood within the whole sample. Low scorers on venturesomeness were more strongly affected by RTD in terms of feelings of inactivity and negative feelings compared to high venture patients. Our data did not show a significant effect of RTD on mood self-ratings. However, the findings must be considered as preliminary and require further replication, in particular as they could be due to sampling bias.Human Psychopharmacology Clinical and Experimental 03/2009; 24(2):87-94. DOI:10.1002/hup.1002 · 1.85 Impact Factor
- Bipolar Disorders 09/2009; 11(5):557-8. DOI:10.1111/j.1399-5618.2009.00725.x · 4.89 Impact Factor