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Serotonergic contribution to boys' behavioral regulation.

Nantel-Vivier A, Pihl RO, Young SN, Parent S, Bélanger SA, Sutton R, Dubois ME, Tremblay RE, Séguin JR - PLoS ONE (2011)

Bottom Line: However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition.Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors.

View Article: PubMed Central - PubMed

Affiliation: Psychology Department, McGill University, Montreal, Canada.

ABSTRACT

Objectives: Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure.

Method: Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500 mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered.

Results: Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.

Conclusions: The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors.

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Related in: MedlinePlus

Physical aggression trajectories from 17 to 84 months.
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pone-0020304-g001: Physical aggression trajectories from 17 to 84 months.

Mentions: Developmental trajectories of physical aggression [65], [66], spanning ages 17 to 84 months, were modeled based on mother ratings for 512 children of the original sample.The developmental trajectory method allows for a summary of population heterogeneity on a certain characteristic, over time. Polynomials are used to represent developmental trajectories varying in level and shape, identifying subgroups of individuals displaying distinct patterns of behaviors over time [66]. Group membership in trajectory models is not absolute, as represented by the posterior probabilities of group membership, consisting in the probability for each individual of belonging to each trajectory estimated from the sample. The maximum probability rule is used to assign individuals to the trajectory to which they have the highest probability of belonging (see Nagin [66] for a complete discussion of developmental trajectory analyses). As shown in Figure 1, a two-group model of physical aggression over time was estimated in which 46 percent of children followed a high developmental trajectory whereas 54 percent of children followed a low/stable developmental trajectory. Within the high physical aggression trajectory 103 boys had a posterior probability in the top quartile. Families of 59 of these boys could be contacted. Exclusion criteria were the presence of a serious medical illness, history of head injury, and current use of prescription medications, with the exception of stimulant medication. Participants taking one of the exception drugs had to be on the same dosage regimen for at least one month to be included in the study. They were also asked not to take their medication on the day of testing, in line with the indicated medication washout period. One boy was excluded from participation based on the medication criteria. Two boys were excluded due to the presence of a medical illness (one with a diagnosis of diabetes, one with a diagnosis of epilepsy). The parents of 23 of the 56 remaining boys consented to participate. Mean age at the time of the study was 123.2 months (SD = 2.8 months).


Serotonergic contribution to boys' behavioral regulation.

Nantel-Vivier A, Pihl RO, Young SN, Parent S, Bélanger SA, Sutton R, Dubois ME, Tremblay RE, Séguin JR - PLoS ONE (2011)

Physical aggression trajectories from 17 to 84 months.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3105989&req=5

pone-0020304-g001: Physical aggression trajectories from 17 to 84 months.
Mentions: Developmental trajectories of physical aggression [65], [66], spanning ages 17 to 84 months, were modeled based on mother ratings for 512 children of the original sample.The developmental trajectory method allows for a summary of population heterogeneity on a certain characteristic, over time. Polynomials are used to represent developmental trajectories varying in level and shape, identifying subgroups of individuals displaying distinct patterns of behaviors over time [66]. Group membership in trajectory models is not absolute, as represented by the posterior probabilities of group membership, consisting in the probability for each individual of belonging to each trajectory estimated from the sample. The maximum probability rule is used to assign individuals to the trajectory to which they have the highest probability of belonging (see Nagin [66] for a complete discussion of developmental trajectory analyses). As shown in Figure 1, a two-group model of physical aggression over time was estimated in which 46 percent of children followed a high developmental trajectory whereas 54 percent of children followed a low/stable developmental trajectory. Within the high physical aggression trajectory 103 boys had a posterior probability in the top quartile. Families of 59 of these boys could be contacted. Exclusion criteria were the presence of a serious medical illness, history of head injury, and current use of prescription medications, with the exception of stimulant medication. Participants taking one of the exception drugs had to be on the same dosage regimen for at least one month to be included in the study. They were also asked not to take their medication on the day of testing, in line with the indicated medication washout period. One boy was excluded from participation based on the medication criteria. Two boys were excluded due to the presence of a medical illness (one with a diagnosis of diabetes, one with a diagnosis of epilepsy). The parents of 23 of the 56 remaining boys consented to participate. Mean age at the time of the study was 123.2 months (SD = 2.8 months).

Bottom Line: However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition.Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors.

View Article: PubMed Central - PubMed

Affiliation: Psychology Department, McGill University, Montreal, Canada.

ABSTRACT

Objectives: Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure.

Method: Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500 mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered.

Results: Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.

Conclusions: The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors.

Show MeSH
Related in: MedlinePlus