Page 43 - Age of onset of disruptive behavior of residentially treated adolescents -Sjoukje de Boer

Introduction
In epidemiological research, Moffitt (1993) found that a relatively small proportion of the population engaged in antisocial behavior at a very young age. In
about a quarter (Veenstra et al., 2009) to half (Moffitt et al., 1996) of these children 3 this disruptive behavior was limited to childhood, the remainder of this group were
labeled life-course-persistent (LCP), because of the continuous course of their antisocial behavior. A larger group was found to be involved in antisocial behavior only
during adolescence, therefore their behavior was labeled adolescence-limited (AL). Although during adolescence these groups do not differ in frequency and seriousness
of offending, it is argued that they differ in etiology, prognosis and classification of
their behavior as either normative or pathological (Moffitt, 1993, 2003; Moffitt et al.,
2008; Moffitt et al., 2002).
This paper tests the classification of these two hypothetical prototypes in an inpatient sample of youths who had severe disruptive behavior combined with psychiatric disorders. Disruptive behavior includes aggression, oppositional behavior, status offences (e.g., running away, truancy, substance abuse), and property violations (e.g., lying or deceiving, selling drugs, vandalism). Replication of findings from general population studies in clinical populations is important, because findings then become clinically useful (Moffitt et al., 2008). In clinical populations it is often difficult to classify adolescents as having LCP or AL disruptive behavior, as information of childhood disruptive behavior is not always present, or difficult to collect retrospectively. As persistence of the behavior is even more difficult to determine retrospectively, and it is unclear whether disruptive behavior in adolescence will persist in later life we choose to use the terms early-onset (EO) and adolescent-onset (AO). Adolescents with severe disruptive behavior who also had disruptive behavior in childhood, we label as EO; adolescents in this group have a significant chance to further develop as those in Moffitt’s LCP group. The group of adolescents who did not have disruptive behaviors in childhood, we label as AO; adolescents in this group will presumably develop as those in Moffitt’s AL group.
A set of risk indicators that is relatively easy to collect, or that is already collected in clinical process, and is strongly predictive of EO versus AO disruptive behavior, helps the clinician to assess the likelihood that an adolescent belongs to the
41