Low Serotonin, Cholesterol, and Violent Behavior
Beatrice Golomb, Psychology, University of Southern California
Research Grant, 1996, 1997
We conducted several studies evaluating the link between physiological factors and violence. First, we reviewed the literature linking low and lowered cholesterol to violence and to lowered brain serotonin activity. (Low brain serotonin activity has been linked to suicide and violence against others; and to reduced “harm avoidance.”) We found that many different classes of literature converged to support a connection, including studies of populations in whom cholesterol was measured, who were followed across time for cause of death (including violent death); studies of suicide in psychiatric populations; studies of violence in institutionalized criminals; and “meta-analyses” (pooled analyses) of clinical trials comparing cholesterol-lowering drugs to placebo, in which the cause of death was stated. In addition to findings in humans, there were also studies in which it was found that monkeys assigned to a cholesterol-lowering diet were more aggressive (toward other monkeys) and had lower measures of brain serotonin than those monkeys that were not so assigned. This study, and a follow-up letter, were published in the Annals of Internal Medicine in 1998.
We found that persons with low cholesterol at baseline were significantly more likely to be arrested for violent crimes against others, an effect that remained present after controlling for potential "confounding" factors (factors that might be linked to both cholesterol and violence, like age, sex, alcohol, and educational status).
In a second study, we collaborated with an investigator from the University of Stockholm, and gained permission from the Swedish government to merge major databases in Sweden, to examine whether low cholesterol was linked to arrests for violent crime against others. Cholesterol had been measured in a population (over seventy thousand individuals) in a region of Sweden called Varmland, in the mid-1960s, and a computerized police database became available in 1966, providing follow-up information on arrests. We gained permission to merge cholesterol information with alcohol information, police arrest records, the Swedish Central Person Registry (which provided information on subjects’ age and sex, for instance), the Swedish education registry, and the Swedish mortality registry. We found that persons with low cholesterol at baseline were significantly more likely to be arrested for violent crimes against others, an effect that remained present after controlling for potential “confounding” factors (factors that might be linked to both cholesterol and violence, like age, sex, alcohol, and educational status). This work was published in the Journal of Psychiatric Research in 2000.
In a third study, we collaborated with investigators from the Helsinki Heart Study in Finland to examine whether there was a connection between “insulin sensitivity” and future suicide and accident, studying persons who had been screened for possible participation in the Helsinki Heart Study. (The “insulin resistance” syndrome is a prediabetic condition that includes a suite of correlated findings: persons with insulin resistance tend to have low HDL-cholesterol, high systolic blood pressure, and high “body mass index,” that is, weight as a function of height. Insulin sensitivity, then, refers to persons who are at the other end of the spectrum on these measures, with high HDL-cholesterol, and low systolic blood pressure and body mass index.) We hypothesized that people with markers of insulin sensitivity might be at higher risk of accidental death and suicide (though at lower risk of heart disease). We showed a biochemical mechanism by which insulin sensitivity would be expected to be linked to reduced delivery of tryptophan to the brain (and thus, potentially, reduced serotonin production, because tryptophan is the substrate for the “rate-limiting” reaction in serotonin production). The study found that people with one or more insulin sensitivity markers, including high HDL-cholesterol, low systolic blood pressure, and low body mass index, were more likely to experience death from accident and suicide than persons without these factors; and the more markers of insulin sensitivity they had, the greater this risk became. This finding was published in the Journal of Clinical Epidemiology in 2002.
Bibliography
Golomb BA. "Cholesterol and violence: Is there a connection?" Annals of Internal Medicine 1998; 128:478-487.
Golomb B. "Cholesterol and violence: is there a connection?" Annals of Internal Medicine 1998; 129:669-70.
Golomb BA, Stattin H, Mednick SA. "Low cholesterol and violent crime." Journal of Psychiatric Research 2000; 34:301-309.
Golomb BA, Tenkanen L, Alikoski T, et al. "Insulin sensitivity markers: Predictors of accidents and suicides in Helsinki Heart Study screenees." Journal of Clinical Epidemiology 2002; 55:1-7.