an examination of the factor structure of the psychopathy checklist

(Leschied et al., 2001; Moretti, Catchpole, & Odgers, 2005). These girls are more likely
than non-violent girls and both violent and non-violent boys to have been attacked on
their way to or from school, physically abused at home, sexually abused or coerced into
sexual relations (Pepler & Sedighdeilami, 1998). Finally, although the abuse of drugs
and alcohol contributes to aggression in both sexes, chronic use of drugs seems to be
strongly related to ongoing participation in violence particularly among girls (Auditor
General of BC, 2000).
Considering the increase in both the number and severity of offences committed
by female youth, it is imperative to understand these girls’ motivations for aggression.
Aggression is a heterogeneous construct that stems from multiple causes and consists
of subtypes, each reflecting a range of pathology. Recognizing the heterogeneous
nature of aggression, Berkowitz (1993) theorized the existence of two primary types:
reactive and instrumental. Reactive aggression is defined by failing to inhibit responses
to apparent provocation or frustration (see Schmitt & Newman, 1998), whereas
instrumental aggression is defined by the presence of planning and the lack of affect
(see Meloy, 2006). Thus, a critical differentiation between reactive and instrumental
aggression concerns the motive of aggression (Raine et al., 2006). Although violence
can be conceptualized as either reactive or instrumental, these categories are not
mutually exclusive, and it has been proposed by some that an aggressive act may
contain elements of both (Bushman & Anderson, 2001). In response to attacks on the
potential artificiality of the instrumental-reactive dichotomy (Dempster et al., 1996; Hart
& Dempster, 1997), Woodworth and Porter (2002) suggested classifying violent
offences into one of four categories: (a) purely reactive, (b) reactive/instrumental, (c)
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