Abstract
This paper provides an overview of a series of issues relating to continuity and discontinuity in externalising disorders including conduct disorder, attention deficit disorder and substance use disorders in childhood and adolescence. These issues include: (a) the assessment of stability and change; (b) the origins of behavioural stability; (c) the origins of behavioural change; and (d) the preventive and clinical implications of research into behavioural stability and change. It is concluded that future research into this area should involve: (a) further research into the genetic factors underlying externalising disorders; (b) continued research into the developmental progressions; (c) refinement and revision of measurement methodologies; and (d) greater use of designed experimentation to examine the extent to which externalising behaviours are amenable to change through both public health and clinical interventions.