Seasonal Affective Disorder, or SAD, affects a great number of people in Ohio at this time of year, and according to a new study publicized this week, there may be a genetic foundation. Here’s an excerpt from Science’s article on the study linking sleep and mood to a possible genetic mutation, and we hope you’ll click the link below to see the full story.
A poor night’s sleep is enough to put anyone in a bad mood, and although scientists have long suspected a link between mood and sleep, the molecular basis of this connection remained a mystery. Now, new research has found several rare genetic mutations on the same gene that definitively connect the two.
Sleep goes hand-in-hand with mood. People suffering from depression and mania, for example, frequently have altered sleeping patterns, as do those with seasonal affective disorder (SAD). And although no one knows exactly how these changes come about, in SAD sufferers they are influenced by changes in light exposure, the brain’s time-keeping cue. But is mood affecting sleep, is sleep affecting mood, or is there a third factor influencing both? Although a number of tantalizing leads have linked the circadian clock to mood, there is “no definitive factor that proves causality or indicates the direction of the relationship,” says Michael McCarthy, a neurobiologist at the San Diego Veterans’ Affairs Medical Center and the University of California (UC), San Diego.
To see whether they could establish a link between the circadian clock, sleep, and mood, scientists in the new study looked at the genetics of a family that suffers from abnormal sleep patterns and mood disorders, including SAD and something called advanced sleep phase, a condition in which people wake earlier and sleep earlier than normal. The scientists screened the family for mutations in key genes involved in the circadian clock, and identified two rare variants of the PERIOD3 (PER3) gene in members suffering from SAD and advanced sleep phase. “We found a genetic change in people who have both seasonal affective disorder and the morning lark trait” says lead researcher Ying-Hui Fu, a neuroscientist at UC San Francisco. When the team tested for these mutations in DNA samples from the general population, they found that they were extremely rare, appearing in less than 1% of samples.