Reduced central nervous 5-HT neurotransmission in youth with ADHD influences ratings of a virtual opponents`extraversion aâ‚¬“ Effects of trait-aggression
Objective: Evidence from animal and human studies suggests that the neurobiology of aggressive behaviour and extraversion is linked with changes in serotonergic (5-HT) neurotransmission. The present study investigated the effects of diminished central nervous 5-HT neurotransmission following rapid tryptophan depletion (RTD) in youth diagnosed with attention deficit/hyperactivity disorder (ADHD). The study assessed the participants' opponent ratings after the experience of competing against a fictitious opponent in a competitive reaction time game (CRT) whilst under the influence of depletion/placebo. Method: 22 boys diagnosed with ADHD were subjected to a double-blind within-subject crossover-design, receiving RTD on one day, and on a further day a tryptophan balanced placebo. 4.5 hours after RTD/placebo intake they were subjected to provocation of aggressive behaviour using the CRT and asked to produce opponent ratings. Results: aâ‚¬Å“Low aggressiveaâ‚¬ boys showed significantly higher extraversion ratings of their fictitious opponent compared to those of aâ‚¬Å“high aggressiveaâ‚¬ boys under RTD versus placebo. Conclusion: The data support evidence that changes in 5-HT neurotransmission are involved in the neurobiological underpinnings of extraversion experienced by children and adolescents with ADHD. Future research with healthy controls and both genders is required to control for developmental and disorder-related effects.
Aggression; Serotonin; Rapid Tryptophan Depletion; ADHD; Opponent ratings