| Dreary, dismal days without the sun may do | | | | At higher latitudes more people are diagnosed |
| more than dampen our spirits. They might just | | | | with as they are exposed to less sunlight and |
| impact the cognitive skills of those who battle | | | | colder and harsher winters. |
| depression, according to some new work that | | | | Women are more often diagnosed with this form |
| appears in the July 28 online issue of | | | | of depression than men. For symptoms to |
| Environmental Health. | | | | receive an official diagnosis of SAD, they must |
| This is the first research to try and link light | | | | repeat for two years in a row, without |
| exposure and cognition, though earlier studies | | | | depression at other times of the year. |
| have shown that our mood can depend on the | | | | The researchers speculate that cognitive |
| amount of sun we see (Seasonal Affective | | | | impairment brought on by depression and lack of |
| Disorder SAD) | | | | sunlight might improve using the same light |
| The work involved a team of American | | | | therapy as with SAD. |
| researchers led by Shia Kent of the University of | | | | Earlier work has shown a strong link between |
| Alabama at Birmingham who used cross-sectional | | | | SAD and other lingering forms of depression. It's |
| data for 14,474 people over 45 years old | | | | also accepted that depression often becomes |
| participating in a project investigating stroke | | | | more pronounced during the darker months of |
| incidence and risk factors, to look for links | | | | the year. |
| between depression, cognitive function and | | | | The study also confirmed melatonin and serotonin, |
| sunlight. | | | | both already implicated in depression, as being |
| The team employed NASA weather data for the | | | | involved in cognitive function issues. |
| United States to check for match-ups between | | | | These two brain chemicals have been named as |
| the days of bright sunlight and levels of cognitive | | | | factors in serious brain diseases like Alzheimer's |
| functioning in those with, and without, depression. | | | | and Parkinson's, as well as sleeping disorders. |
| The cognitive function of the subjects was | | | | Cerebral blood flow has also been implicated in |
| measured using a validated questionnaire; an | | | | cognitive functioning; earlier work confirming that |
| accepted depression scale assessed depression. | | | | such blood flow is affected by light. |
| Once the data was collected, advanced statistics | | | | Also of note, the relationship between sunlight and |
| were used to assess any link between average | | | | cognitive function didn't hold true for those who |
| sun exposure and cognitive function. | | | | weren't depressed, according to the research. |
| Kent summarized the findings of the team, "We | | | | This suggests that it may be that the same |
| found that among participants with depression, | | | | mechanisms involved in depression might also be |
| low exposure to sunlight was associated with a | | | | involved in cognitive functions. |
| significantly higher predicted probability of cognitive | | | | If you are depressed, or deal with SAD, trying to |
| impairment. This relationship remained significant | | | | spend some time in the sun (safely, of course) is |
| after adjustment for season. This new finding | | | | a simple way to put the findings of this intriguing |
| that weather may not only affect mood, but also | | | | research to the test for yourself. You might also |
| cognition, has significant implications for the | | | | consider learning more about light therapy, which |
| treatment of depression, particularly seasonal | | | | would have you sitting comfortably under a full |
| affective disorder". | | | | spectrum light for a few hours a day all through |
| Seasonal affective disorder, SAD, is a relative | | | | the winter months. |
| newcomer to the scene, first referenced in print | | | | Also good is a walk outdoors, even in the cold, as |
| back in 1985, and is known to bring depressive | | | | it can be a refreshing, invigorating source of |
| symptoms as the days grow shorter in the fall | | | | natural sunlight and keep Seasonal Affective |
| and winter, with symptom improvement as spring | | | | Disorder SAD at bay. |
| returns. | | | | |