Oxford-backed research examines sleep and depression

Researchers at the University of Birmingham, supported by Oxford Health and the NIHR Oxford Health Biomedical Research Centre, analysed data from more than 15,000 children taking part in the long-running Children of the 90s project, based around Bristol.

They tracked night-time sleep from six months to seven years of age, collecting information at several points in early childhood, and then followed participants’ self-reported depression symptoms from age 12.5 through to 22.

Only a relatively small group of children experienced ‘persistently shorter’ sleep throughout childhood, but within that group the risk of long-lasting depression was noticeably higher.

Those children were found to be almost twice as likely to report consistently high levels of depressive symptoms during adolescence and early adulthood compared with peers who slept for longer.

Lead author Dr Isabel Morales-Muñoz said it was persistent poor sleep across childhood, rather than the odd bad night, that appeared to be linked to the increased risk.

She stressed that poor sleep is common in childhood and that most children in the study did not go on to develop enduring depression, even if they sometimes slept badly.

The team also emphasised that the overall proportion of children who experienced persistent depressive symptoms remained relatively small, even among those with long-term sleep issues.

In a paper published in the journal European Child & Adolescent Psychiatry, the researchers said theirs is the first study to demonstrate a detrimental effect of shorter night-time sleep from infancy through childhood on more severe and long-lasting depression in later years.

They also examined whether inflammation in the body might help explain the connection between sleep and mental health, but found only mixed evidence for this possible biological pathway, suggesting other factors are also likely to be involved.

The authors said the findings underline how important it is to support good sleep habits early on, describing sleep as a ‘modifiable’ part of children’s lives that can often be improved without medical treatment.

Suggested steps include keeping to regular, earlier bedtimes, cutting back screen time before bed, encouraging plenty of physical activity during the day and creating a calm, consistent sleep environment.

They added that while such changes are not always easy for families, improving children’s sleep can bring immediate benefits for daily life and may also help reduce the risk of mental health problems as they grow older.