Sleep Upset Paired with Depression in Kids

PITTSBURGH, Jan. 2 -- Poor sleep is a frequent companion of depression in children, according to researchers here.

Just like in adults, sleep disturbances and depression go hand in hand in children, reported Xianchen Liu, M.D., Ph.D., of the University of Pittsburgh, in the Jan. 1 issue of Sleep.

In research conducted as part of a larger study in Hungary, Dr. Liu and colleagues found that 72.7% of 553 children with a current depressive episode also reported a sleep disturbance.

Among the study participants, 53.5% had insomnia alone, 9.0% had hypersomnia alone, and 10.1% had both disturbances, the researchers found.

Analysis of the patients revealed that average depression severity scores -- on the Interview Schedule for Children and Adolescents-Diagnostic Version -- differed significantly (at P<0.001 for all comparisons) between children without a sleep disturbance and children with insomnia alone, hypersomnia alone, or insomnia as well as hypersomnia.

Also, children with both sleep disturbances had significantly more severe depression than did children with insomnia or hypersomnia alone (at P< 0.001 and P<0.01, respectively).

On the other hand, there was no significant difference between children with insomnia and hypersomnia alone.

What's more, children with more than one form of sleep disturbance were more likely to be in a recurrent episode of depression and to have had the illness longer than those with either insomnia or hypersomnia alone, Dr. Liu and colleagues said.

Depressed girls were more likely to have sleep disturbance than boys -- 77.0% versus 69.2%, which was statistically significant at P<0.05 -- but age had no significant effect.

When the researchers controlled for other depressive symptoms, age, and sex they found that:

• Insomnia alone independently correlated with depressed mood, diurnal variation, and agitation.
• Hypersomnia alone correlated with weight loss, weight gain, and worthlessness.
• Insomnia plus hypersomnia correlated with anhedonia, weight loss, agitation, distinct sadness, and guilt.

"These results suggest that three groups of sleep-disturbed children are distinguishable from each other in the presentation of depressive symptoms," the researchers said.

The differences may indicate that different treatments are needed, depending on the extent and type of sleep disturbance, but clinical trials and longitudinal studies will be needed to determine that, Dr. Liu and colleagues said.

The study has several important limitations, the researchers said. For one thing, the clinical interview from which the data were gathered was not designed to assess sleep patterns and disorders, so that there is no data on bedtime, morning rise time, and sleep duration.

Also, no objective measures of sleep were used in the study, such as nocturnal polysomnography.

The children ranged in age from 7.3 to 14.9 years, but the researchers did not collect data on puberty, so that the effects of pubertal development are a potential confounding element.

In addition, they pointed out that "no causal relationships can be concluded based on the current cross-sectional analysis. For example, the relationship between sleep disturbance and depressive symptoms and comorbid anxiety disorders may be bidirectional."