Research has shown that even preschool children can suffer from depression, and now new evidence suggests their symptoms can be divided into subtypes in a way that reflects what’s seen in adults.

A study of 156 children between the ages of three and about five-and-a-half found that among the 54 diagnosed with depression, two groups emerged. One group had characteristics similar to those of adults diagnosed with a subtype of depression known as “melancholic” depression. In adults, melancholic depression is considered to be more severe than some other types of depression, and research has shown it to be distinct from a more “reactive” depression that arises in response to a traumatic event.

From the new study findings, it does appear that depressed preschoolers can be broken into two groups along the lines used for adults, the study’s lead author, Dr. Joan L. Luby of Washington University in St. Louis, told AMN Health.

The children in the study whose depression mirrored adult melancholic depression tended to have more severe symptoms and a strong family history of depression, and all of them suffered from so-called anhedonia - a lack of interest in the things that normally occupy young children, including play. These children also appeared to be “slowed down” or “restless” more often than the other depressed children in the study.

Fifty-seven percent of the depressed children in the study fell into the group with anhedonia.

The second group - which Luby and her colleagues refer to as “hedonic” - was distinct in that the children’s moods did brighten at times and they were able to take pleasure in things like play. They also had a higher rate of stressful life events, which is consistent with the “nonmelancholic” type of depression seen in adults, Luby and her colleagues note in the report.

It’s possible, Luby said, that some young children may suffer from depression in reaction to a stressful situation, while for others - those with anhedonia - symptoms are biologically based. Research in adults has suggested that anhedonia may have genetic underpinnings and possibly be related to dysfunction in the brain’s “reward system.”

If it’s the case that preschoolers can be separated into melancholic and nonmelancholic groups, it’s important to make the distinction, according to Luby. Adults with melancholic depression have been shown to respond to therapy differently than those with other types of depression, she pointed out.

Currently, young children with depression are treated with forms of psychotherapy geared for their age group, such as “play” therapy, but more research is needed to judge the effectiveness of such treatment, Luby said.

SOURCE: American Journal of Psychiatry, November 2004.