Elevation and reduction of plasma tryptophan and their effects on aggression and perceptual sensitivity in normal males

Data from experimental animals suggest that 5-hydroxytryptamine (5HT) may have an inhibitory effect on aggression, while clinical studies have found a correlation between pathological aggression and low brain 5HT. To investigate this relationship further we used amino acid mixtures designed to raise or lower the levels of the 5HT precursor, tryptophan. Normal male subjects were given tryptophan-depleted, balanced, or tryptophan-supplemented ammo acid mixtures and tested for aggression 5 hours later. The balanced amino acid mixture served as a control for the tryptophan depletion and supplementation. Testing for aggression was done using the Buss paradigm in which subjects deliver electric shocks to a (nonexistent) partner in response to stimulus tones. Duration and intensity of shock delivered were the measures of aggression, while responsivity to the stimulus tones was the measure of perceptual sensitivity. Neither tryptophan supplementation nor tryptophan depletion had any effect on these measures of aggression or perceptual sensitivity. We conclude that raising or lowering the synthesis of brain 5HT through alterations in tryptophan availability does not influence aggression in normal males as measured by the Buss task.     

Moral Values Reveal the Causality Implicit in Verb Meaning

Prior work has found that moral values that build and bind groups—that is, the binding values of ingroup loyalty, respect for authority, and preservation of purity—are linked to blaming people who have been harmed. The present research investigated whether people's endorsement of binding values predicts their assignment of the causal locus of harmful events to the victims of the events. We used an implicit causality task from psycholinguistics in which participants read a sentence in the form “SUBJECT verbed OBJECT because…” where male and female proper names occupy the SUBJECT and OBJECT position. The participants were asked to predict the pronoun that follows “because”—the referent to the subject or object—which indicates their intuition about the likely cause of the event. We also collected explicit judgments of causal contributions and measured participants' moral values to investigate the relationship between moral values and the causal interpretation of events. Using two verb sets and two independent replications (N = 459, 249, 788), we found that greater endorsement of binding values was associated with a higher likelihood of selecting the object as the cause for harmful events in the implicit causality task, a result consistent with, and supportive of, previous moral psychological work on victim blaming. Endorsement of binding values also predicted explicit causal attributions to victims. Overall, these findings indicate that moral values that support the group rather than the individual reliably predict that people shift the causal locus of harmful events to those affected by the harms.     

Exploring Wellbeing in Youth with Vision Impairment: Insights for Vision Rehabilitation

Applied Research in Quality of Life - This article explores the discussions of 21 young Australians (aged 12–25) with vision impairment regarding their lived experiences and what it meant for...     

Prevalence of ADHD and comorbid disorders among elementary school children screened for disruptive behavior

In the context of a school-based prevention of conduct disorder program, 7,231 first- through fourth-grade children were screened for cross-setting disruptive behavior. Frequencies of DSM-III-R psychiatric disorders and patterns of comorbidity were assessed. We also examined the association of psychiatric diagnosis with child and parent characteristics to determine differential risk based on diagnostic subgroups. Attention deficit hyperactivity disorder (ADHD) and oppositional-defiant disorder (ODD) were the most frequent diagnoses. Mood and anxiety disorders were infrequent as single diagnoses. Patterns of comorbidity demonstrated that both externalizing and internalizing disorders commonly cooccurred with ADHD. More severe degrees of psychopathology and psychosocial risk accrued to the subgroup of youths with ADHD plus a comorbid externalizing disorder.This study was supported by grant MN-46584 from the National Institute of Mental Health.