We have all heard about just how important sleep is not only for us physically, but for us to mentally and emotionally too.  A new Japanese study only further confirms that fact, proving that people who do not get a good night’s sleep are, on average, about twice as likely to suffer from depression down the road.

The study was performed by a team from the Tokyo Medical University and was done over a course of two years.  As clinical professor of psychiatry at Harvard Medical School, Dr Srinivasan Pillay, said, “The study is interesting because it confirms again that there is a connection between sleep abnormalities and depression.”  He goes on to say, “What it does not tell us is whether sleep abnormalities are the cause of depression or something else.  It tells us there is an association between the two.”

This is a particularly startling fact, as a reported one-fifth of the entire Japanese population suffers from insomnia.  This means that 20% of the population is at a higher risk for other psychiatric disorders, like depression, anxiety, and even substance abuse.  Until this study, however, not a whole lot of research had been done in Japan.

Dr Yuiche Inoue led his team of researchers starting in 2005, sending out two surveys to close to 3000 adults in Daisen, a town in the Tottori Prefecture.  One of the surveys was to help survey and measure a person’s insomnia symptoms, and the other was used to try and detect their depression symptoms.  The insomnia survey allowed the researcher to try and analyze different categories of sleep disturbance.  This included sleep quality, the amount of time it took for each person surveys to fall asleep, their sleep “efficiency”, their sleep duration, as well as whether or not they experienced any daytime dysfunction.

Two years later both surveys were sent out again, however only just over half of the original participants had agreed to complete them.  Still, this was enough for the researchers to come to a few conclusions.

First, it was concluded that one’s quality of sleep was more important than the actually quantity of sleep, at least in terms of whether or not they would develop depression.  Having poor sleep quality and daytime dysfunction could raise the possibility of depression by 60 and 80 percent.

It was also found that having disturbed sleep could elevate one’s chance of develop depression by 30 percent, and for those who had difficulty falling asleep or who used medications for sleep, had an increased risk of 20 percent.

Though this study is alarming, psychiatrist Dr Carole Lieberman of the UCLA’s Neuropsychiatric Institute still says that the study is flawed.  Of the study, she has said that it “does not prove that insomnia causes depression, but rather that insomnia is often associated with depression.”  She had also made note of the fact that many of the people who reported insomnia in the initial 2005 were already depressed.

While this study may not have revealed anything particularly new or ground breaking, it does only further confirm just how important having a good night’s rest is for our overall well-being.