Serotonin and behavior -- from vanGoozen article

5-HT and Aggression In an influential thesis, Spoont (1992) argued that 5-HT stabilizes information processing in neural systems, resulting in controlled behavioral, affective, and cognitive output, whereas disturbances in 5-HT activity result in altered information processing tendencies. High levels of 5-HT were proposed to lead to excessive restraint, cognitive inflexibility and anxiety, whereas low levels were thought to lead to behavioral disinhibition and distractibility. Coccaro and Kavoussi (1996) proposed a model for impulsive aggression in which the threshold for aggressive action, given the proper environmental circumstances, is modulated by overall 5-HT system function. Diminished serotonergic function is thought to disinhibit aggression directed against the self and others, perhaps by sharpening sensitivity to stimuli that elicit irritation and aggression and blunting sensitivity to cues that signal punishment(Spoont, 1992). =============== To date, only three studies have measured 5-HIAA in CSF in children (Castellano´s et al., 1994; Kruesi et al., 1990, 1992; see Table 3). Kruesi et al. (1990) found that children with DBD and/or ADHD had lower 5-HIAA levels compared with children suffering from obsessive-compulsive disorder. CSF 5-HIAA concentrations were also inversely correlated with ratings of aggressive behavior in the disruptive group. At the 2-year follow-up, CSF 5-HIAA levels were found to be a predictor of the severity of physical aggressive behavior and poor outcome (Kruesi et al., 1992). In contrast, Castellano´s et al. (1994) found in their study of 29 boys with ADHD that CSF 5-HIAA levels were positively correlated with measures of aggression and impulsivity.