پرخاشگری تکانشی زنان: چشم انداز پژوهش خواب

The rate of violent crimes among girls and women appears to be increasing. One in every five female prisoners has been reported to have antisocial personality disorder. However, it has been quite unclear whether the impulsive, aggressive behaviour among women is affected by the same biological mechanisms as among men. Psychiatric sleep research has attempted to identify diagnostically sensitive and specific sleep patterns associated with particular disorders. Most psychiatric disorders are typically characterized by a severe sleep disturbance associated with decreased amounts of slow wave sleep (SWS), the physiologically significant, refreshing part of sleep. Among men with antisocial behaviour with severe aggression, on the contrary, increased SWS has been reported, reflecting either specific brain pathology or a delay in the normal development of human sleep patterns. In our preliminary study among medication-free, detoxified female homicidal offenders with antisocial personality disorder, the same profound abnormality in sleep architecture was found. From the perspective of sleep research, the biological correlates of severe impulsive aggression seem to share similar features in both sexes.

Impulsive aggressive behaviour that includes physical aggression directed towards others, self-mutilation, suicide attempts, domestic violence, substance use and property destruction presents a challenge to both research and health care system. The economic and social cost of aggressive behaviour is huge (Scott, Knapp, Henderson, & Maughan, 2001), and so far both pharmacological and behavioural treatment interventions have been quite ineffective (Malone, Delaney, Luebbert, Cater, & Campbell, 2000). As a symptom, aggression overlaps a number of psychiatric disorders, but it is commonly associated with personality disorders, in particular antisocial (ASP) personality disorder (Eronen, Hakola, & Tiihonen, 1996). As ASP is linked with a pervasive pattern of disregard for and the violation of the rights of others, it is not surprising, that the highest prevalence rates of ASP are found in prisons and forensic settings (American Psychiatric Association, 2000). In a study by Fazel and Danesh (2002), as many as 47% of male prisoners had ASP.

One of the consistent alterations in normal ageing is a decrease of SWS, while REM sleep is less affected (Bliwise, 2000). The sleep patterns of children are characterized by high amounts of SWS (Bes, Schulz, & Salzarulo, 1991), but a quantitative change in SWS occurs during puberty and a reduction in SWS by almost 40% during the second decade of life has been reported (Carscadon & Dement, 2000). As ageing proceeds, a gradual decline in SWS is observed (Bliwise, 2000). It is possible that the decline in SWS that normally occurs in the course of aging is delayed in ASP. Whether this reflects specific brain pathology, or a maturational delay in the normal development of central nervous system in the course of aging, needs to be clarified with future studies. It is also possible that antisocial offenders with difficulties in maintaining normal arousal levels during the daytime are exhausted in the evening, and according to the homeostatic model of non-REM sleep regulation (Borbély, 1982), sleep more deeply at night. To verify this hypothesis, in the future, a study with 24 h EEG recordings is warranted in this patient group. And, of course, the hypothesis of central nervous system maturational delay and the idea of daytime hypoarousal affecting increased deep sleep are not incompatible. What we can say is that severe female aggression may be associated with profound changes in sleep architecture, and from the perspective of sleep research, the biological correlates of severe impulsive violence seem to be similar in both sexes.