Seasonal affective disorder (SAD) is a type of depression that has a seasonal pattern. It typically affects people during winter, hence why it is also sometimes known as “winter” depression, and improves during spring.
What causes seasonal affective disorder?
SAD’s causes aren’t fully understood, but it is generally linked to reduced exposure to sunlight during the autumn and winter months. The leading idea behind SAD is that a lack of sunlight disrupts activity in a part of the brain called the hypothalamus.
This can have three main effects: decreased production of the mood-boosting hormone serotonin, increased production of the sleep-inducing hormone melatonin and disruption of circadian rhythms, the body’s internal clocks.
SAD may also have a genetic element, as it seems to sometimes run in families.
What are the symptoms?
SAD’s symptoms can vary in severity from p….