A new study validates the existence of major depressive disorder (MDD) in children as young as 3 years and shows that those with major depression at this young age are almost 4 times more likely than their age-matched counterparts to have depression 2 years later.
The findings should go a long way toward silencing those who doubt the existence of preschool depression, study investigators say.
“The skeptics — and there have been many — seem to feel that the most important issue is whether depressed preschoolers grow into depressed children, adolescents, and adults, and this paper is the first step in demonstrating that that is, in fact, the case,” lead author Joan L. Luby, MD, from Washington University School of Medicine in St. Louis, Missouri, told Medscape Psychiatry.
Dr. Luby added that this research also demonstrates that preschool depression is not clinically insignificant and does not spontaneously resolve.
The study is published in the August issue of Archives of General Psychiatry.
Stressful Life Events
From May 2003 to March 2005, researchers used the Preschool Feelings Checklist (PFC), a 20-item parent-reported symptom list, to recruit subjects 3 to 5.11 years of age from pediatricians’ offices, daycare centers, and preschools in and around St. Louis. The study was designed to oversample for preschoolers who had or were at risk for depression.
To assess symptoms, researchers used the Preschool-Age Psychiatric Assessment (PAPA), an interviewer-based caregiver-reported diagnostic tool. The PAPA uses age-appropriate Diagnostic and Statistical Manual of Mental Disorders, 4th ed (DSM-IV) criteria to rate symptoms. The PAPA also assesses stressful life events. For young children, this could include changing daycare centers or the death of a pet.
To determine family psychiatric history, researchers administered the Family Interview for Genetic Studies to primary caregivers who provided relevant information on study subjects’ first- and second-degree biological relatives.
Those who completed the PFC and who met the inclusion criteria attended the Early Emotional Development Program at the Washington University School of Medicine for a comprehensive 3- to 4-hour laboratory assessment.
While children completed measures of emotional, cognitive, and social development, primary caregivers were interviewed about the child’s psychiatric symptoms, developmental skills, and impairments.
Children were categorized and placed into 1 of 3 groups: those with MDD (n = 75); those who met the criteria for anxiety and/or disruptive disorders but who did not have MDD (n =79); and those with no disorder (n = 146).
Researchers repeated the assessments of the parents and children at 12 months and again at 24 months.
Baseline MDD a Major Risk Factor
To obtain data on the continuous course of MDD, researchers administered MDD modules of the PAPA by telephone to 157 subjects who were depressed or who had 4 or more symptoms of MDD and/or anhedonia and who were considered prodromal.
The investigators found that preschoolers with MDD at baseline were 11.3 times more likely to be depressed at follow-up than children with no disorders.
After adjustment for key risk factors, including stressful life events, the study showed that preschool children with MDD had an odds ratio (OR) of 3.64 for developing subsequent MDD.
Recurrence was defined as an episode of depression that occurred 6 months or more after the initial episode. Children with chronic depression were those who had MDD at 4 or more assessment periods.
Of the 54 preschoolers with MDD at baseline who completed the MDD modules of the PAPA, 40% remained depressed or were found to have had a recurrent episode at 24-month follow-up. Overall, 10 participants (19%) had a chronic course of depression.
In addition to MDD at baseline, having a family history of affective disorders at baseline was another predictor of later MDD (OR, 1.07; P < .001).
Disruptive Disorders Predictive
Interestingly, anxiety wasn’t a predictor of later MDD, but having a disruptive disorder was (OR, 3.04; P = .006). This was also the case with older children, said Dr. Luby.
Disruptive disorders go beyond the typical confrontational behavior sometimes displayed by energetic preschoolers. “It crosses the threshold; these are kids who get kicked out of daycares and preschools,” she said.
Symptoms of depression in preschoolers are the same as those in older children and adults, with some exceptions. “When we assess for the disorder in younger children, we have to assess for age-adjusted manifestations of symptoms, so for example, we don’t look at decreased libido,” said Dr. Luby.
Physicians look for intense and sustained loss of interest in activities and play, changes in sleep patterns, and sustained decreased joyfulness, she said. “One of the things that make preschoolers harder to diagnosis is that they are inherently joyful.”
Another red flag is intense guilt or shame, she added. “Preschoolers who feel guilty about things that aren’t their fault or feel excessively guilty after a wrongdoing or who feel excessive shame and preoccupation with shame and then decreased energy may be suffering depression.”
Knowing depression can affect very young children could help spur age-appropriate prevention and treatment programs, said Dr. Luby.
“Applying an intervention at a time when the brain is more changeable or neuroplastic — just like introducing speech therapy as early as possible for children with speech problems — [leads to] the hope or possibility that treatment might be more effective and actually change the trajectory of the disorder,” she said.
Newly Recognized Phenomenon
Preschool depression is such a newly recognized phenomenon that there are not yet adequate scientific data on how best to treat it. However, Dr. Luby and her colleagues are testing a parent–child psychotherapy intervention in a randomized controlled trial.
It is difficult to determine how common preschool depression is, but 1 study found the prevalence rate to be 2.1%, similar to that for school-aged children.
Asked by Medscape Psychiatry to comment on the study findings, David Fassler, MD, from the University of Vermont College of Medicine in Burlington, said he hopes studies such as this one will help parents, teachers, and pediatricians recognize the signs and symptoms of preschool depression and make sure young children get the help they need.
“Depression in very young children is relatively rare, but it definitely does occur,” said Dr. Fassler. “Without treatment, it can have a devastating and often lasting effect on a child’s social and emotional development.”
The researchers have disclosed no relevant financial relationships.