Disturbances in glucose metabolism are of importance for violent behaviour in men, but studies in women are lacking. We used the 5 h-oral glucose tolerance test (OGTT) in this study of 17 female psychiatric patients, selected for violent behaviour directed against themselves (deliberate self-harm) and 17 healthy controls matched for age and BMI. Following OGTT, patients had higher glucose levels at 30 min (p = 0.007) and increased glucagon area under the curve (p = 0.011). Since a co-morbid eating disorder might affect results, we as a post-hoc analysis subgrouped the patients and found that the increased glucagon levels only were present in patients with an eating disorder. In contrast, those without an eating disorder showed a significantly lower p-glucose nadir (p = 0.015) and unaltered glucagon levels compared to controls. There were no significant differences in insulin and C-peptide levels between patients and controls. We conclude that deliberate self-harm in women may be associated with alterations in carbohydrate metabolism in certain groups. Eating disorder is a confounding factor.
Several studies have investigated the relationship between glucose metabolism and impulsive aggressive behaviour in healthy men as well as in male forensic psychiatry patients. During the oral glucose tolerance test (OGTT), a reactive hypoglycaemic tendency after the initial rise in plasma (p-)glucose has been found in habitually violent men (Bolton, 1973, Benton et al., 1982, Virkkunen and Huttunen, 1982, Virkkunen, 1982, Virkkunen, 1983, Virkkunen, 1986, Virkkunen and Narvanen, 1987 and Virkkunen et al., 1994). In some of these men hypoglycaemia has persisted throughout the OGTT. The counter-regulation of hypoglycaemia is a complex system, involving a decrease in insulin secretion and an increase in several counter-regulatory factors, augmenting p-glucose, of which the hormone glucagon is the most potent during the immediate phase (Cryer, 1993). The hypoglycaemic tendency found in habitually violent men may thus be explained by either an imbalanced insulin secretion, which does not decrease when p-glucose is reduced, or an insufficient secretion of the counter-regulatory factors raising p-glucose. Early studies by Virkkunen and coworkers have found increased insulin levels, proposing this as the cause of the hypoglycaemia (Virkkunen, 1982 and Virkkunen, 1983). A recent study, examining men with habitually violent behaviour, found that they, compared with healthy controls, had significantly lower basal glucagon levels, which could be a possible explanation for their hypoglycaemic tendencies (Virkkunen et al., 2007).
The men in these studies often showed self-aggression and had made several violent suicide attempts (Virkkunen and Narvanen, 1987). In psychiatric care, violent behaviour among patients is often directed towards the self, and includes deliberate self-harm as well as attempted suicide. This kind of violent behaviour is commonly, but not exclusively, associated with borderline personality disorder, a co-morbid diagnose in many of the patients studied by Virkkunen (1986). Furthermore, epidemiological studies among adolescents in the United States have found that aggressive behaviours directed against oneself, and aggressive behaviours towards other people often occur in the same individuals (Borowsky et al., 2001 and Centers for Disease Control and Prevention, 2004).
Treatment of deliberate self-harm is traditionally psychotherapeutic although hospitalization as well as polypharmacy combining anti-depressant, anti-psychotic as well as tranquilizing medication is common. In patients with severe deliberate self-harm, treatment effect is often limited, and mortality rates in completed suicide are high. Examining glucose metabolism in these patients is a completely new approach and if altered glucose metabolism is found, new treatments might develop as complement to the present ones.
Whereas disturbed glucose metabolism has been found in aggressive men, it is not known whether this is the case also in women. We therefore investigated insulin and glucagon secretion and glucose tolerance during OGTT in women with deliberate self-harm. Our primary hypotheses were:
(1)
Women with deliberate self-harm have high self-rated physical aggression.
(2)
Women with deliberate self-harm have lower p-glucose nadir (lowest value measured during the OGTT) compared to healthy controls.
(3)
Women with deliberate self-harm have increased insulin secretion during OGTT compared to healthy controls.
(4)
Women with deliberate self-harm have decreased glucagon secretion compared to healthy controls.
