Sleep disorders could be directly linked to the likelihood of an adolescent going on to develop depression.
This is the according to the findings of a five-year study completed by UT Southwestern Medical Center researcher and professor of psychiatry Dr Uma Rao.
Experiencing rapid-eye-movement (REM) sleep earlier is one of the characteristics of depression and adolescents with a family history of the illness but without being diagnosed with depression themselves were found to also reach REM sleep quickly.
Dr Rao explained: "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."
In other news, a team of scientists have discovered a genetic mutation which they believe causes some people to need more sleep than others.
DEC2 has been linked to the amount of sleep required by individuals and provides an insight into the regulatory mechanism of sleep.