to be focused on this period of life. In addition to universal prevention programs, Figure 2-3 suggests that there may be a window of opportunity lasting two to four years between the first symptom and the full-blown disorder, when preventive programs might be able to reduce the rate of onset of specific disorders. Recently developed measures (Egger and Angold, 2006) now make it possible to identify children with symptoms of several disorders at an early stage. In addition, developmentally informed interventions that aim at known antecedent risk factors during childhood and early adolescence can provide important opportunities for prevention.
To determine whether the number of new cases is rising or falling over time, it is important to distinguish between incident (new) cases and newly referred or treated cases. For example, according to one survey of clinical referrals, the number of children and adolescents in the United States treated for bipolar disorder increased 40-fold from 1994 to 2003, to about