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Over one million people are known to commit suicide every year, making it the tenth-leading cause of death worldwide. Suicide events among young adults may be due to highly variable sleep schedules and they may not be aligned to depression. Previous findings reveal that a group of undergraduate students who delayed bedtime of 2.08 am limited their sleep time of 6.3 hours. It was observed that they were more prone to highly variable sleep schedules and with time of mean sleep changeable by three hours and time of sleep changeable by 2.8 hours.

Experts evaluated 49 undergraduate students between 19 and 23 years of age who were more prone to suicides; 71 percent were female. Sleep variability revealed suicidal risk at one week and three weeks and it was the only sleep measurement which determined depression severity. The only sleep-related variable to forecast mood lability was sleep irregularity which also indicated increasing suicidal symptoms. In order to study the psychology and neurobiology of mood disorders, suicide, and related conditions, a three week study was conducted at the Florida State University Laboratory.

“To our knowledge, this is the first study to evaluate the unique association between sleep and suicide risk using an objective assessment of sleep and a prospective study design,” said principal investigator Rebecca Bernert, PhD, Fellow in the Department of Psychiatry and Behavioral Sciences at Stanford University. “We found that a high degree of irregularity in sleep predicted increases in suicidal symptoms, conferring risk above and beyond the influence of depression. Given that the relationship between sleep disturbances and suicide appears to exist independent of depressed mood, we propose that sleep disturbances may instead confer risk via impaired mood regulation and increased mood lability.”

Using the beck depression inventory and beck scale for suicide the severity of the symptom at baseline, one week and three week was assessed. Sleep data was obtained with the help of wrist actigraphy for one week. Sleep variability was calculated as a total of the standard deviation of sleep onsets and offsets. Using daily visual analogue scale mood ratings mood lability was estimated in the same time frame. According to Bernert identifying sleep irregularity as the main reason for suicidal reasoning may have important clinical associations.

“Compared to other suicide risk factors such as a past suicide attempt, disturbed sleep is modifiable, often visible and amenable to treatment,” she said. “In this way, the study of sleep may inform suicide risk assessment and represent a clinically unique opportunity for intervention.”

Bernet and Joiner published a review of the publication in 2007 on sleep problems and suicide risks in the journal Neuropsychiatric Disease and Treatment. Several theories expressed neurobiological factors such as serotonergic neurotransmission played an important role in the link between sleep and suicide; however this has to be tested further.

The findings were presented on Tuesday, June 8, 2010, in San Antonio, Texas, at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC.