SEROTONIN, AGGRESSION: EVIDENCE MOUNTS

Growing evidence links abnormal levels of the brain chemical serotonin to impulsive aggression, suicide and a wide range of behavioral abnormalities (see related article, Crime Times, Vol. 2, No. 3, Page 4). Three recent studies, using three different types of subjects, further support the idea of a serotonin/aggression link.

Alan Unis et al. studied 43 boys between the ages of 13 and 17. All were inmates at a residential facility for juvenile offenders, and all were diagnosed with conduct disorder-symptoms of which include chronic stealing, lying, arson, property destruction, fighting, cruelty to animals and people, weapons use, aggression, truancy, and running away from home.

The researchers report that whole blood serotonin levels were higher in teens with childhood-onset conduct disorder-the most severe form of the disorder-than in those whose behavior problems began in adolescence. In addition, Unis et al. found a positive correlation between whole blood serotonin levels and the severity of subjects' current and past offenses. They also found that treatment center staff rated subjects with higher blood serotonin levels as more socially impaired. These findings, the researchers say, support an earlier study by Pliszka et al., who found a correlation between conduct disorder ratings and whole blood serotonin in juvenile offenders.

Noting that research links low cerebrospinal fluid (CSF) levels of serotonin to aggression, the researchers explain that a number of biological mechanisms can lead to both high blood levels of serotonin and reduced CSF availability. (Editor's note: (see related article, Crime Times, Vol. 3, No. 4, Page 1 for an example.)

The researchers say, "Our findings are consistent with a relationship between [serotonin] dysregulation and aggressive behavior in incarcerated adolescent boys with conduct disorder, particularly of childhood onset."

In related research, Anthony Cleare and Alyson Bond found that even in males with no history of psychiatric problems, low serotonin levels may correlate with levels of aggression and hostility. Cleare and Bond administered the serotonin-releasing agent D-fenfluramine to 35 subjects (20 females and 15 males) and found an inverse correlation between measures of serotonin function and measures of hostility and aggression in male subjects. Their data, the researchers say, "provide modest support for the theory of a link between reduced serotonergic activity and increased trait aggression in healthy males." No similar correlation was seen in female subjects.

A third study linking abnormal serotonin levels and aggression was recently reported by Antonia New and colleagues. New et al. studied the response of 97 personality-disordered patients to a fenfluramine challenge, and found that those with a history of self-injury or suicide attempts showed evidence of abnormalities of the serotonergic system. New et al. theorize that "self-injurious behavior, like suicidal behavior, represents a form of self-directed aggression," and may be associated with a decrease in central serotonin function.

"Platelet serotonin measures in adolescents with conduct disorder," A. S. Unis, E. H. Cook, J. G. Vincent, D. K. Gjerde, B. D. Perry, C. Mason, and J. Mitchell, Biological Psychiatry, Vol. 42, No. 7, Oct. 1, 1997, pp. 553-559. Address: Edwin H. Cook, Dept. of Psychiatry, Univ. of Chicago, MC 3077, 5841 S. Maryland Ave., Chicago, IL 60637.

"Does central serotonergic function correlate inversely with aggression? A study using D-fenfluramine in healthy subjects," Anthony J. Cleare and Alyson J. Bond, Psychiatry Research, 69, 1997, pp. 89-95. Address: Anthony J. Cleare at a.cleare@iop.bpmf.ac.uk.

"Serotonergic function and self-injurious behavior in personality disorder patients," A. S. New, R. L. Trestman, V. Mitropoulou, D. S. Benishay, E. Coccaro, J. Silverman, and L. J. Siever, Psychiatry Research, 69, 1997, pp. 17-26. Address: Antonia S. New, Psychiatry Service (116A), Bronx VA Medical Center, 130 W. Kingsbridge Rd., Bronx, NY 10468.

Related Articles: [1997, Vol. 4]