problem behaviors but not depression into adulthood; and some with eventual bipolar disorder (e.g., Harrington et al., 1990; Weissman et al., 1999b).
Adolescent-onset depressions are noteworthy for several factors. One is that increasing rates of adolescent depression in recent years (e.g., Kessler et al., 2003) imply, among other things, that the etiology is substantially psychosocial, with significant cultural shifts in recent decades that have created stressful experiences and reduced resources and contribute to depressive experiences (e.g., Seligman et al., 1995). Another issue is the enormous divergence in rates of depression for girls and boys beginning in adolescence (e.g., reviewed in Hankin and Abramson, 2001). The dramatic increases in girls’ rates of depression compared with boys’ rates clearly requires etiological models that can explain such differences. For example, different models emphasize genetic (e.g., Silberg, Rutter, and Eaves, 2001), hormonal (e.g., Angold et al., 1999), stress exposure and stress processes (e.g., Rudolph, 2002; Shih et al., 2006), cultural shaping of values and vulnerabilities (Seligman et al., 1995), and gender-based coping strategies (e.g., Nolen-Hoeksema, 1991).
The childbearing years in general, and those around pregnancy in particular, have attracted special attention with respect to the occurrence of depression and its potential effects on children’s development. A large majority of women experience mild “blues” following delivery of an infant, and between 10 and 20 percent of new mothers experience clinical depression lasting anywhere from several weeks to a year. A smaller proportion, less than 0.5 percent, experience acute psychosis associated with the depression. A recent large-scale epidemiological survey that examined rates of diagnoses in nonpregnant women compared with past-year pregnant women found no differences overall in mood disorders (Vesga-Lopez et al., 2008). However, the rates of major depression were higher in postpartum women compared with nonpregnant women. For all women pregnant in the past year, their depression was associated with not being married, exposure to trauma and stressful life events in the past year, and overall poor health.
The dramatic hormonal changes a woman experiences during and after pregnancy have focused much attention on the biological and hormonal etiological factors of postpartum depression. However, there is widespread agreement that postpartum major depression is not distinct in terms of etiology from depression at other times. In addition to biological risk factors, social stressors, family composition, levels of social support, and especially poorer economic circumstances all contribute to the risk of developing postpartum depression (Bloch et al., 2005; Crouch, 1999; Grigoriadis and