Biological factors in aggression

The European Clinical Aggression Group held its Annual Meeting in Budapest in October 1993. The aim of this Group is to bring together both clinical and basic science researchers in the aggression field to present research findings and to develop new approaches. The topics discussed at the 1993 meeting included studies of factors that provoke aggression and biological markers that are associated with exhibition of aggressive behaviour in humans. Dr Alyson Bond from the Institute of Psychiatry in London, opened the meeting by discussing the relationship between aggression and anxiety. Her presentation examined what factors led severely anxious people to become aggressive, as well as determining the levels of anxiety in people who habitually exhibit aggressive acts. Anxious people find the world a very threatening place. Attitudinal studies have shown that anxious people overestimate the degree of threat associated with a situation and they further underestimate their ability to cope. This triggers a behavioural response of fight or flight. Those anxious people who become aggressive usually experience both fear and anger. Reports describing aggressive thoughts and behaviour in people with panic disorder suggest that aggressive acts may be used to offset a feeling of fear. Psychopaths are a group who are thought to habitually exhibit aggressive behaviour. In a study from an English Special Hospital those psychopaths that had high levels of anxiety and social withdrawal reacted more strongly than nonanxious subjects to situations ranging from mildly annoying to highly threatening (Blackburn, 1993). The most aggressive subjects perceived events as most threatening and they also showed increased anger and arousal. This theme was developed in Dr Bond's own work with patients from the Forensic Unit at the Maudsley Hospital. Those subjects who were lowest in anxiety also had lower aggression and anger scores whereas patients with high anxiety demonstrated increased risk of aggression. The extent to which aggressive behaviour can be provoked by psychotropic drugs was addressed by Professor Hans-Jurgen MoIler from the University of Bonn. The furore engendered by the report from Harvard of 6 patients who had committed suicide or made determined suicidal attempts while receiving fluoxetine had led to an extensive metaanalysis which revealed no hint of fluoxetine provoking suicidal urges (Beasley ef al., 1991). However, in a large American study examining over 1000 outpatients receiving a variety of antidepressants, patients treated with a tricyclic antidepressant in combination with fluoxetine had a slightly increased risk of suicide attempts compared to those treated with monotherapy. It may be of course that these patients are on this combination because they are a more high-risk group or because they have not responded to antidepressants taken alone. Other work has suggested that increasing noradrenergic drive can increase the risk of suicide. (Feuerstein et al. (1993) suggested this hypothesis and Rouillon et al. (1991) found in a maintenance study comparing maprotiline with placebo that there were suicides and suicide attempts only in the maprotiline group. Perhaps more important is a possible interaction when psychotropic drugs are given to patients with antisocial and borderline personality traits. In a frequently cited study by Soloff ef al. (1986) examining the effect of amitriptyline and haloperidol in patients with borderline personality disorder, there was an increase in aggressive or suicidal behaviour only in the group of amitriptyline nonresponders and these findings were significant when compared to the placebo non-responders. A similar study with borderline patients receiving alprazolam reported a significant increase in discontrol in patients who were taking alprazolam compared to placebo (Gardner and Cowdrey, 1986). The speaker stressed that such a disinhibiting mechanism could well be more prone to occur in patients with a history of or a tendency to aggressive or