Depression is one of the most common mental disorders in adolescence and is found in children as young as kindergarten age. Unfortunately, the disorder often lasts into adulthood, but an NTNU study gives cause for optimism.

PhD candidate Ida Sund Morken and her colleagues at NTNU’s Department of Psychology have investigated the extent to which depression in childhood increases the risk of developing new depression later, as well as looked at other forms of stability in depression.

The researchers used the database from the Trondheim Early Secure (TESS) study, where about one thousand children and their parents have follow-ups every other year, including clinical interviews.

“Depression is considered a persistent or recurring condition. But research provides few answers as to why children and adolescents stay depressed or have relapses over time,” says Morken.

The scar hypothesis

The scar hypothesis suggests that being depressed has consequences that contribute to the depression being maintained over time, or that make the person more susceptible to new depression. The consequences can be social withdrawal or changes in the brain.

“If the hypothesis is correct, we have reason for a certain optimism: If we manage to prevent or reduce early depression, the risk of the child developing depression later in childhood and adolescence decreases. The problem is that we don’t know if there’s support for the scar hypothesis,” says Morken.

Some underlying cause could perhaps be making children vulnerable instead, such as persistent factors that increase the risk of depression recurring repeatedly. Possible causes could be neglect on the part of the parents, everything from gross abuse to emotional absence, or vulnerability that lies in our genes.

The “stability” of depression

The duration of depression up through children’s growing up has several aspects. According to Morken, the research literature provides knowledge about how stability is expressed, and the prevalence of depression at different ages at the group level. Research has also been done on how individuals with depression are doing – their “position” in depression as compared to their peers.

“In preventing and treating depression, it’s just as important to know how the individual child’s depression is doing – compared to him- or herself. What is the risk of the child remaining as depressed as he or she is now?

4-14 year olds

Morken’s study builds on existing stability research in how depression manifests itself, stability at the group level (prevalence) and stability in comparison with peers.

“We’re the first researchers to examine the stability of the individual’s depression and the effect of early depression on later depression. Using statistical analysis methods, we examined these types of stability in the 4-14 year old age range.

Greater stability than expected

“We found that depression is most common in adolescents, but that it can occur as early as preschool age. The study suggests that children’s level of depression is relatively stable compared to their peers. The children who scored highest on depression continued to fare the worst even at a later age,” Morken says.

The researchers found that stability is even stronger when individual children are compared with their own level of depression over time.

“Children who score high at an early stage thus continue to have a high level of depression – regardless of their peers,” she says.

Grounds for hope

“Our most important finding, however, is that a change in depression also turns out to be valid at a later date. Early worsening of depressive symptoms makes it more likely that the difficulties will recur. This is in line with the scar hypothesis, that depression in itself can lead to persistent and recurring depression. The symptoms of depression, even in preschool and early school age, seem to increase the susceptibility to, or have an effect on, later depression.

Fortunately, improving depression at one stage also contributes to improvement in the long run.

“The good news is that treatment and preventive measures that lead to improvement, can quite likely counteract persistent symptoms and relapses,” says Morken.

Treatment

The researcher believes the finding gives solid grounds for optimism.

“I think this is good news and a strong argument for spending resources on early prevention and treatment, not only in the vulnerable adolescent period but also as young as kindergarten and primary school age,” says Morken.

The study does not address what types of preventive measures or forms of treatment should be used. Previous research has shown that various established treatment methods can yield good results, depending on the context and the individual child.