By Nestor Lopez-Duran PhD
In the current issue of Archives of General Psychiatry, Joan Luby and her team at Washington University in St. Louis presented the findings of a powerful longitudinal study of depression in early childhood. In this new article, Dr. Luby examined the continuity and stability of early childhood depression. Specifically, her team wanted to explore whether preschool depression was a transient developmental phase or a more chronic condition. Surprisingly, this question has not been fully answered mostly because of the limited knowledge we have about early childhood depression.
The study included 306 preschool children (age 3 to 5) recruited from community sources in the St. Louis area. However, this is not a normative community sample, as the recruitment strategy was designed to recruit children at risk for depression and other psychiatric disorders (for example due to a family history of depression). This is a common and appropriate recruitment technique when the objective of the study is to examine the disease process rather than to provide normative or epidemiological information about the condition. The participating children and their parents underwent a series assessments upon entry to the study (baseline) and then 12 (wave 1) and 24 (wave 2) months later.
- At baseline 25% (N=75) children met diagnostic criteria for major depression disorder, 26% (N=79) met criteria for other psychiatric disorder, and 47% ( N= 146) did not meet criteria for any psychiatric disorder.
- At baseline, there was a significant difference in age among the groups, with depressed kids being more likely to be older than the kids in the other psychiatric diagnostic group. There were no gender differences between the depressed kids and the other groups.
- At baseline, the depressed kids were more likely to have experienced more traumatic events than the non-depressed kids.
- Below you can see the analysis of the longitudinal progression of MDD compared to other disorders. Looking only at the top section of the draw, compared to kids without any psychiatric disorder at base line, kids with MDD were 11 times more likely to have MDD vs No disorder at follow up. Similarly, kids with MDD were 7 times more likely than kids with no disorder to have MDD vs. Psychiatric disorder at follow up. Finally kids with MDD were not more likely than the no disorder group to have another psychiatric disorder vs. no disorder. A Similar interpretation can be applied to the other two draws.
- The researchers also examined the predictors of depression at follow up. Four factors were significant predictors of MDD at follow up: having MDD at baseline (increased odds of 264%), having a family history of an affective disorder, having disruptive disorder at baseline, and having family income levels below $20,000.
- Below you can also see the trajectory of MDD based on different severity at baseline. Severe MDD appears to follow a chronic trajectory. Those with less severe MDD follow two trajectories: a recovery, and a recovery-relapse trajectory. The authors could not identify any factors that would help us predict the trajectories (e.g., chronic vs. recover) among kids with MDD.
There are two critical findings presented in this study. One is that MDD in preschool is highly stable and predictive of future MDD, specially when baseline MDD is severe (more than 50% of the kids with initial MDD continued to have MDD at follow up). Thus, it does not appear that MDD in preschool is a developmental transitional phase. Second, MDD appears to be a risk factor uniquely for MDD. That is, unlike more general internalizing symptoms, which are predictive of a number of different disorders, the presence of MDD in preschool does not seem to be an indicator of future general psychopathology, but instead it is mostly an indicator of future MDD. This suggests that the MDD diagnosis obtained at this age truly reflects a somewhat homogeneous disease process that is in place and is not simply a reflection of a non-specific dysregulation of emotion that could precede a number of conditions.
Luby, J., Si, X., Belden, A., Tandon, M., & Spitznagel, E. (2009). Preschool Depression: Homotypic Continuity and Course Over 24 Months Archives of General Psychiatry, 66 (8), 897-905 DOI: 10.1001/archgenpsychiatry.2009.97