A variety of malleable risk factors may be available for intervention for any given disorder. Intervention should start as early in life as possible, other things being equal. But in many situations, an intervention later in life may still be effective, even if some will already have the disorder. Combining the cumulative distributions with the attributable risk and with cost and outcome factors can aid policymakers in making decisions on priorities in the use of resources.
Figure 5.2 ,Figure 5.3, Figure 5.4 through 5.5 present two cumulative distributions each. The distribution on the right focuses on the age at which the individual first meets full criteria for the given DIS/DSM-III diagnosis. For this distribution, onset must occur during the one-year prospective period of follow-up. The population being studied includes all those who had never met criteria for diagnosis at the beginning of the follow-up period. It includes those with no symptoms, as well as those with some symptoms of disorder, but not meeting full DSM-III criteria. The distribution on the left focuses on the age at which a prodromal sign or symptom related to that disorder first occurred, as reported by the individuals who had developed the disorder by the end of the follow-up period. Dotted lines mark the twentieth and fiftieth percentiles, and age values for these are recorded on the figure. The area between the two curves gives a rough outline of the prodromal period.
In the text and figures below, data are presented regarding prevalence and prodromal periods in individuals who have experienced the onset of disorder.* During these prodromal periods, precursor signs and symptoms were present, and ideally these individuals could have been identified as being at high risk. The data were, however, subject to the problems of retrospective recall by individuals with a current mental disorder.
The essential feature of conduct disorder, according to DSM-III-R, is a persistent pattern of conduct in which the basic rights of others and major age-appropriate societal norms or rules are violated. This diagnosis is made among children and adolescents under age 18 when at least 3 of 13 possible criteria have been present for at least six months (see Table 5.1). The behavior pattern may be simultaneously present in
*These data were prepared in 1992 by William Eaton and Mohamed Badawi, both from The Johns Hopkins University, explicitly for this report.