Understanding and Preventing Violence, Volume 2: Biobehavioral Influences (1994)
Chapter: CONCLUDING STATEMENT
blood-borne indices of 5-HT function is even more problematic than the CSF 5-HIAA measures. At present, it is unclear whether or not these peripheral indices are direct reflections of 5-HT activity in brain. It would be highly premature to propose the use of these measures from CSF or blood as diagnostic or prognostic tools for the propensity to engage in violent or aggressive behavior.
An alternative test of 5-HT activity, particularly in the hypothalamus, is to challenge individuals with a 5-HT agonist and measure the subsequent increased release in prolactin from the anterior pituitary. "Assault" and "irritability" ratings in patients with DSM-III axis 11 personality disorders inversely correlated with the peak prolactin response to the 5-HT-releasing agent fenfluramine (Coccaro et al., 1989). Again, future studies will have to determine the mechanisms for the reduced prolactin response and delineate more precisely the relevant patient population.
In a series of follow-up studies, Virkkunen et al. (1989a) and Linnoila et al. (1989) studied Finnish alcohol-abusing males, previously imprisoned for arson or manslaughter, and classified them as either impulsive or nonimpulsive on the basis of premeditation, monetary gain, and familiarity with the victim. The nadir of blood glucose during a glucose tolerance test predicted recidivism in 3 out of 13 cases and nonrecividism in 43 out of 44 cases. Adding the variable "CSF 5-HIAA" concentration as a second step to the discriminant analysis improved the predictive classification by two more cases. By itself, CSF 5-HIAA concentration failed to predict any recidivism, but CSF 5-HIAA and MHPG concentration classified more than 70 percent correctly for a history of suicide attempts. These studies point to a complex interplay between responsivity to glucose challenge, aspects of monoamine metabolism as reflected in CSF concentrations, and familial and current alcoholism as they relate to suicide history, impulsive homicide, and criminal behavior.
CONCLUDING STATEMENT
Anatomically discrete brain serotonin systems contribute importantly to brain mechanisms subserving aggressive, defensive, and muricidal behavior in animals and to a range of impulsive and violent behaviors in humans. The critical brain regions extend from 5-HT cell groups in the raphe nuclei in the mesencephalic region to the hypothalamic area and further to the hippocampal,
