The way teenagers sleep can provide a clue to their longer-term risk of developing depression or bipolar disorder.
Erratic sleeping patterns were an often overlooked feature of “basically all mood disorders and all psychiatric disorders”, explains Dr Naomi Rogers.
There was now a growing understanding of the importance of sleep for good mental health and of how disrupted sleep could point to future mental illness, she said.
“In people who develop depression, often you can trace back and find they have had early sleep disturbance,” Dr Rogers, from the University of Sydney’s Brain & Mind Research Institute, told AAP on Friday.
“We know that disturbed sleep occurs in basically all mood disorders and all psychiatric disorders, and the more disturbed sleep patterns are we tend to see worse mood symptoms.
“But whether (disturbed sleep) is an early sign, or risk factor, we are not yet sure.”
Dr Rogers has studied sleep-wake cycles, and circadian rhythms, of young people with depression, bipolar disorder and schizophrenia.
She observed results unlike ordinary adolescent sleep patterns, in which young people typically go to bed late then need to sleep in but are able to do so only on weekends.
Young people with mental illness were more likely to show “no pattern”, she said.
“… A couple of nights of long sleep, a couple of nights of short sleep … it’s the instability that we think is important,” Dr Rogers said.
She cautioned parents to not look at a child’s sleep-wake cycle in isolation, but to also look for evidence of “withdrawing”, such as quitting their team sport or not seeing as much of their friends or poorer school grades.
Noticing these early warning signs could lead to an earlier diagnosis of a mental health problem and allow an earlier intervention with milder treatments.
“It’s the whole picture of looking at their social interactions, their sleep wake-cycle and mood … people tend to forget about the sleep part,” Dr Rogers said.
“We also need more psychologists, psychiatrists and GPs to be asking about the sleep … there is a strong link between sleep and mood.”
As a general rule, she said adults should aim for eight hours’ sleep a night “though we know many people get a lot less than that” while children need nine to ten hours.
Sleep was even more important for children during periods of intense study, as research showed more information was retained after a good night’s sleep rather than “cramming” into the early hours.
“We also say, for children, they should have a technology-free bedroom – don’t have the temptation of the computer or the phone there because they will get up,” Dr Rogers said.
“Also the light from it can be alerting as well. It is not getting children into that relaxed state they need for bed.”
Dr Rogers spoke at the 22nd Annual Scientific Meeting of the Australasian Sleep Association and Australasian Sleep Technologists Association conference, in Christchurch, New Zealand.