Washington University researchers discovered children who had depression as preschoolers were 2.5 times more likely to suffer from the condition in elementary and middle school than kids who were not depressed at very young ages.
Prior research has shown that depression in preschoolers is often influenced by a caregiver (mother’s) depression.
For the study, a novel research method included the use of two-way mirrors to observe children from preschool age through middle school.
The study has been published in The American Journal of Psychiatry.
“It’s the same old bad news about depression; it is a chronic and recurrent disorder,” said child psychiatrist Joan L. Luby, MD.
“But the good news is that if we can identify depression early, perhaps we have a window of opportunity to treat it more effectively and potentially change the trajectory of the illness so that it is less likely to be chronic and recurring.”
The investigators followed 246 children, now ages nine to 12, who were enrolled in the study as preschoolers when they were three to five years old.
The children and their primary caregivers participated in up to six annual and four semiannual assessments.
They were screened using a tool called the Preschool Feelings Checklist, developed by Luby and her colleagues, and evaluated using an age-appropriate diagnostic interview.
As part of the evaluation, caregivers were interviewed about their children’s expressions of sadness, irritability, guilt, sleep, appetite, and decreased pleasure in activity and play.
In addition, researchers used two-way mirrors to evaluate child-caregiver interactions because the team’s earlier research had shown that a lack of parental nurturing is an important risk factor for recurrence of depression.
The study was designed to follow children as they grew and to evaluate them for depression and other psychiatric conditions.
However, if children were found to be seriously depressed or in danger of self harm, or if their caregivers requested treatment, they were referred to mental health providers.
Currently, there are no proven treatments for depression that arises in the preschool years. Even in depressed adults, available treatments and medications are effective only about half the time.
At the start of the study, 74 of the children were diagnosed with depression.
When the researchers evaluated the same group six years later, they found that 79 children met the full criteria for clinical depression based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V).
More than 51 percent of the 74 children who originally were diagnosed as preschoolers also were depressed as school-age kids. Only 24 percent of the 172 children who were not depressed as preschoolers went on to develop depression during their elementary and middle school years.
Luby’s group also found that school-age children had a high risk of depression if their mothers were depressed.
And they noted that children diagnosed with a conduct disorder as preschoolers had an elevated risk of depression by school age and early adolescence, but this risk declined if the children were found to have significant maternal support.
But neither a mother with depression nor a conduct disorder in preschool increased the risk for later depression as much as a diagnosis of depression during preschool years.
“Preschool depression predicted school-age depression over and above any of the other well-established risk factors,” Luby explained.
“Those children appear to be on a trajectory for depression that’s independent of other psychosocial variables.”
Luby said her findings continue to contradict doctors and scientists who have maintained that children as young as three or four could not be clinically depressed. She advocates including depression screenings in regular medical checkups for preschoolers, but she said such monitoring is unlikely to begin anytime soon.
“The reason it hasn’t yet become a huge call to action is because we don’t yet have any proven, effective treatments for depressed preschoolers,” she explained.
“Pediatricians don’t usually want to screen for a condition if they can’t then refer patients to someone who can help.”
Luby now is testing potential parent-child psychotherapies that appear promising for preschoolers with depression, but it’s too early to determine whether they work.
Her team also will continue following this group of children through puberty to determine whether depression during preschool remains a risk factor for depression during young adulthood.