If winter days get you down, you’re not alone. You may have seasonal affective disorder, a type of depression triggered by the change of seasons. People with this disorder tend to feel depressed in the fall and winter when there is less sunlight and the days are shorter.

Researchers believe that the lack of sunlight during these months causes changes in our body clock and internal rhythms, leading to depression. The difference between seasonal affective disorder and other types of depression is that symptoms generally lift in the longer, brighter days of spring and summer.

As you might guess, this type of depression is more common for those living in northern states, since those regions have the least amount of sunlight during winter. While it is less prevalent in sunny Southern California, Dr. Kelly Kang, a psychiatrist with UCLA Behavioral Health Associates, says that for the very reason that it is less common, Californians may be less likely to make the connection between their symptoms of depression and the changing seasons – and therefore may not seek help.

To read about the symptoms of seasonal depression and what you can do about it. see this UCLA Health blog.