Mental health professionals involved with the care of
children and adolescents are frequently confronted with
questions about the risk of later troublesome outcomes.
Of particular concern is whether the presence of certain
risk factors warrants the provision of an intervention.
The presence of externalising behaviour symptoms is
regarded by many as the single best predictor of risk for
future conduct disorder and antisocial behaviour
(Loeber, 1991; Lynam, 1996; Moffitt, 1993; Patterson,
1993; Yoshikawa, 1994). These symptoms include aggression against
others, destruction of the personal
property of others, temper tantrums, and noncompliance,
to name but a few. The evidence suggests that when these
behaviours are present in childhood there is an increased
risk for persistent, life-long psychosocial problems
(Loeber, 1982; Loeber & Dishion, 1983; Moffitt, 1993;
Olweus, 1979; Yoshikawa, 1994). For example, a link
between the early onset of externalising behaviours and
the later development of conduct disorder, antisocial
behaviour, and substance abuse has been documented in
both longitudinal and retrospective studies (Caspi,
Moffitt, Newman, & Silva, 1996; Farrington, 1990;
Robins, 1978; Tremblay, Pihl, Vitaro, & Dobkin, 1994;
White, Moffitt, Earls, Robins, & Silva, 1990; Zoccolillo,
Tremblay, & Vitaro, 1996).
The risks associated with externalising symptoms and
the relatively modest effectiveness of treatment for
established cases of conduct disorder and antisocial
behaviour (Kazdin, 1997; Offord, 1989; Offord &
Bennett, 1994) have led to an increased emphasis on the
provision of preventive interventions (Institute of Medicine, 1994;
Reiss & Price, 1996). It has been argued that
intervention should be provided to high-risk children as
early as possible. Claims have been made that even in
nonclinic populations of children as young as 4 and 5
years of age, 50% or more of those with troublesome
externalising symptoms will develop persistent psychosocial
problems (Campbell, 1995; Coie, 1996; Reid, 1993;
Reid & Patterson, 1991).
