SEROTONIN: MARKER FOR AT-RISK CHILDREN?

Children with attention deficit hyperactivity disorder (ADHD) often exhibit severe behavior problems including aggression. Research indicates that the hyperactive children most likely to exhibit chronic aggression are those with a family history of sociopathy-and adult sociopathy, in turn, is linked to low cerebrospinal fluid levels of the serotonin metabolite 5-HIAA (see related article, Crime Times, 1998, Vol. 4, No. 2, Page 1&7).

Curious about the possible relationship between parental sociopathy, childhood aggression, and low serotonin levels, Jeffrey Halperin and colleagues compared four groups of ADHD boys: aggressive boys with and without a parental history of aggressive behavior, and non-aggressive boys with and without a parental history of aggressive behavior. The researchers administered the serotonin-releasing drug fenfluramine to 41 subjects, and measured changes in their plasma prolactin levels. (The magnitude of the prolactin response to fenfluramine is believed to be a measure of overall serotonin function.)

The researchers found that "aggressive boys with a parental history of aggressive behavior had a significantly lower prolactin response to the fenfluramine challenge than aggressive boys without a parental history of aggression"-an indication of reduced serotonin function in the first group. The two groups of non-aggressive boys had a prolactin response midway between those of the aggressive groups. Parental histories of psychiatric symptoms other than aggression did not affect the children's response to the test.

Their findings, Halperin et al. say, indicate that aggressive ADHD boys with a family history of aggression "are neurochemically distinct" from similar children without such a history. They also note that the aggressive children with family histories of aggression exhibited more violent behavior than aggressive children without such a history. The combination of family sociopathy and increased aggression, they say, "suggests that this group is at increased risk for progression toward more severe violent behavior during adolescence/adulthood."

The fact that the positive-family-history group differed from other aggressive children, the researchers say, may explain varying results obtained by other studies of serotonin levels in aggressive children (in comparison to consistent findings of diminished serotonin function in aggressive adults). Perhaps, the researchers suggest, subjects with higher serotonin levels "are more likely to desist in their aggressive behavior."

The researchers caution that their study did not include non-ADHD children or girls, and their findings cannot be generalized to these groups.

In an attempt to trace the roots of antisocial behavior even farther back, John Constantino and colleagues measured levels of 5-HIAA-a metabolite of serotonin-in samples of cerebrospinal fluid from 193 infants. The samples examined by the researchers had been drawn from children hospitalized with fevers.

The researchers report that "levels of 5-HIAA were significantly lower in the infants with family histories of antisocial personality disorder than in the newborns without such family histories."

The researchers say this may indicate that "serotonin mediates one component of genetic liability to antisocial outcome," although the association they detected was only modest.

"Serotonin, aggression, and parental psychopathology in children with attention-deficit hyperactivity disorder," Jeffrey M. Halperin, Jeffrey H. Newcorn, Ilene Kopstein, Kathleen E. McKay, Susan T. Schwartz, Larry J. Siever, and Vanshdeep Sharma, Journal of the American Academy of Child and Adolescent Psychiatry, Vol. 36, No. 10, October 1997. Address: Jeffrey M. Halperin, Psychology Department, Queens College, 65-30 Kissena Boulevard, Flushing, NY 11367.

"CSF 5-HIAA and family history of antisocial personality disorder in newborns," John N. Constantino, Jennifer A. Morris, and Dennis L. Murphy, American Journal of Psychiatry, Vol. 154, No. 12, December 1997. Address: John Constantino, Department of Psychiatry, Washington University School of Medicine, 4940 Children's Place, St. Louis, MO 63110.

Related Article: [1998, Vol. 2]