Sleep patterns can predict depression

Sleep patterns can help predict which children and teenagers might be at greater risk for developing depression, a new study has found.

According to the researchers, depressed adults experience rapid-eye-movement (REM) sleep earlier in the sleep cycle than people who are not depressed.

The US study found that adolescents with a familial risk for depression but without a depression diagnosis experienced shorter REM latency, meaning they reached the REM stage more quickly.

Those adolescents were more likely to develop depression by the end of the five-year study period than those who reached REM sleep later in the cycle.

"Sleep is probably more helpful in determining who is at risk for developing depression than in being a diagnostic marker for depression since REM latency of those adolescents was shorter before they even developed the illness," said Dr Uma Rao, professor of psychiatry at UT Southwestern Medical Center.

Adolescent depression is complex to prevent and treat in part because baseline levels of sleep and other factors used to diagnosis depression are not clearly defined.

“This study is an initial step in determining baseline measures that differentiate healthy adolescents from those who are likely to develop depression, bipolar disorder and other mental diseases as they get older,” said Dr Rao.

The study involved 96 adolescents with no evidence of depression or other psychiatric disorders. At the start of the study, researchers monitored the sleep cycles of participants for three days and collected saliva and urine samples to record cortisol levels. The teens were then monitored for up to five years.

In addition to the sleep finding, researchers found that at the end of the five-year study period, adolescents with higher cortisol levels were more likely than others to develop depression.

The results of the study are published in the journal Neuropsychopharmacology.

[Posted: Thu 13/08/2009]