Adolescent depression is a concern to both clinical and public health professionals, following evidence that children born since World War II have higher rates of depressive disorders, become depressed at an earlier age, and are more likely to commit suicide than were adolescents of earlier generations (Gore, Aseltine, and Colton 1992; Murphy and Wetzel 1980; Klerman and Weissman 1989).  Only recently have researchers of child development begun to think that depressive symptoms in children are more than transient developmental phenomena with little clinical meaning, or that clinical depression occurs among children younger than eight  (Lefkowitz 1980; Lefkowitz and Burton 1978; Digdon and Gottlib 1985; Kovacs 1986).  The belief has been that children are not cognitively developed enough to experience poor self-worth, guilt, hopelessness, and helplessness.  Prior studies have found inconsistent findings regarding the exact prevalence of depression among children, estimates ranging from less that one percent to over five percent (Angold 1988a; Fleming and Offord 1990).  Using data from the Baltimore Prevention Program Study on 1047 first-graders, Edelsohn et al. (1992) and Ialongo et al. (1993) report that six percent of the first-graders self-reported severe levels of depressive symptoms.  Children’s self-reports of depressive symptoms tended to become more stable over time, increasing from a moderately strong degree of stability in first grade to a very strong degree of stability in fifth grade.

Depression among children of the Baltimore Prevention Program Study (Edelsohn et al. 1992; Ialongo et al. 1993) was related to how well the children were able to negotiate a number of salient developmental tasks at entrance to first grade, including academic achievement, peer relations, and attention/concentration in the classroom.  Children who were in the highest quartile of depression were twice as likely to be in the lowest quartile of reading achievement, the lowest quartile of mathematics achievement, the highest quartile of teacher-rated concentration problems, and the lowest quartile of peer-rated likeability. There were no sex differences in the prevalence of depressive symptoms.  However, children from impoverished neighborhoods were found to have higher means scores on the depression measure than their more well-off counterparts. Further, the symptoms of depression were relatively stable over a four-month period. Kellam et al. (1998) used cross-lagged analyses to indicate that the direction of relationship was from fall depression to spring achievement for boys, while for girls, there were reciprocal effects between depression and reading achievement between fall and spring.

One of the most consistent findings in the epidemiology of depression is that adult women are about twice as likely to be depressed as adult men (Nolen-Hoeksema, 1987, 1990; Weissman and Klerman 1977).  This gender difference in the rate of depression is not apparent among preadolescent children (Brooks-Gunn and Petersen 1991; Nolen-Hoeksema 1990); Rutter 1986), but tends to develop around mid-adolescence (Allgood-Merten, Lewinsohn , and Hops 1990; Girgus, Nolen-Hoeksema, and Seligman 1989, 1991; Kandel and Davies 1986; Petersen et al. 1991). 

Several recent reviews of research have indicated that a variety of biological, psychological, and social factors must be considered in order to understand the etiological underpinnings of depression (see especially the reviews by Petersen, Sarigiani, and Kennedy 1991; Nolen-Hoeksema and Girgus 1994; the report of the American Psychological Association’s Task Force on Women and Depression  by McGrath, Keita, Strickland, and Russo 1990; and Sprock and Yoder 1997).  With regard to how the gender differences in depression might develop in early adolescence (between ages of 11 and 15), Nolen-Hoeksema and Girgus (1994) suggest that girls are more likely than boys to carry such risk factors for depression as low focus on instrumentality, high ruminative coping, and low aggression and dominance in interpersonal interactions even before early adolescence.  The authors maintain that it is only when these risk factors interact with certain challenges of early adolescence that girls develop higher rates of depression than boys.  For example, research has suggested that adolescent boys are more likely than girls to like their developing body images, and that body dissatisfaction may account for a substantial part of the gender difference in depressive symptoms.  Nolen-Hoeksema and Girgus mention other challenges which may be faced more frequently by girls than boys such as sexual abuse (which increases substantially for girls during the period between 10 and 14 years of age), and an increase in the pressure to conform to a restrictive social role deemed appropriate for females, including downplaying their competence.