A developmental propensity model of the origins of conduct problems during childhood and adolescence.

In this chapter, we present an overview of a causal model of the origins of conduct problems during childhood and adolescence. We use the term conduct problems to refer to behaviors that violate important behavioral norms or laws. In this sense, both juvenile crimes and DSM-IV symptoms of conduct disorder (CD) are conduct problems. The diagnosis of CD is viewed as the extreme end of the continuum of conduct problems, with the point of demarcation between CD and “normal behavior” reflecting a convention rather than a dichotomy in nature (Lahey et al., 1994). Thus, the present model is applicable to both CD and juvenile delinquency. The milder behavior problems that define DSM-IV oppositional defiant disorder (ODD) are not considered to be conduct problems in this chapter, but we discuss their association with conduct problems. The dependent variable for the model is the youth’s developmental trajectory of conduct problems. In the general terminology of longitudinal data analysis, trajectories are defined by the youth’s intercept (i.e., essentially the level of conduct problems at the youngest age at which conduct problems are measured) and slope (i.e., increasing or decreasing trends over time). In this chapter, we focus on school-age children, from the age of school entry through age 17 years. We believe that it will be possible to extend the present model back in time, however, to encompass the earliest phases of the development of conduct problems. In this chapter, we state hypotheses that are based on data, but we of-