Depression among preschoolers appears to be a continuous, chronic condition rather than a transient developmental stage, according to a report in the August issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

"The validity of major depressive disorder in childhood has been well established, with the disorder now widely recognized and treated in mental health settings," the authors write as background information in the article. However, previous studies have primarily focused on children age 6 and older. Although a growing body of data suggests that depression does exist among preschoolers, skepticism remains about whether it is clinically meaningful or increases the later risk of psychiatric conditions.

Joan L. Luby, M.D., and colleagues at Washington University School of Medicine in St. Louis studied 306 preschoolers age 3 to 6. Of these, 75 met criteria for major depressive disorder, 79 had anxiety or disruptive disorders but not depression and 146 did not meet criteria for any psychiatric disorder. A comprehensive three- to four-hour laboratory assessment was completed at the beginning of the study. While children completed measures of emotional, cognitive and social development, primary caregivers were interviewed separately about the preschoolers' psychiatric symptoms and developmental skills. Similar developmental and behavioral assessments were conducted 12 and 24 months later.

"Preschoolers with depression at baseline had the highest likelihood of subsequent depression 12 and/or 24 months later compared with preschoolers with no baseline disorder and with those who had other psychiatric disorders," the authors write. After controlling for other demographic variables and risk factors, preschoolers with depression at the beginning of the study had a four times greater likelihood of having depression one and two years later than preschoolers without depression.

The condition also showed a chronic and recurrent course among preschoolers-in a subset of 119 preschoolers with depression or depressive symptoms who were screened by phone at six and 18 months, 57 percent of those with depression had an episode during at least two follow-up points during study and 18 percent followed a chronic course, defined as having an episode in at least four waves of the study.

"These results underscore the clinical and public health importance of identification of depression as early as preschool," the authors conclude. Early intervention during the preschool period has proved effective in other childhood disorders, they note. "Therefore, study findings that demonstrate longitudinal stability and homotypic continuity of preschool major depressive disorder suggest that earlier interventions for major depressive disorder during the preschool period may be an important area for investigation in the search for more effective treatments for childhood major depressive disorder."

Funding for this study was provided by a grant from the National Institute of Mental Health.