Depression can happen for several reasons. Some patients may have a genetic predisposition, while other cases are triggered by trauma or other negative life events. Patients may live with a range of symptoms, from chronic sadness, hopelessness or anxiety to sleep disorders, pain and lack of energy.
When we talk about depression, we usually refer to a chronic condition that may take the patient years to gain control over. But there is another form that has been recognized by mental health experts since 1987. This form of depression only affects the sufferer at certain times of the year, and is triggered by reduced sunlight, such as during winter's short, cloudy days and long nights.
It is called seasonal affective disorder, or SAD. But a new study suggests that it may not actually exist.
The study is based on a massive phone survey of more than 34,000 U.S. adults, CBS News reports. The subjects were asked questions about how many days in the prior two weeks they had felt depressed. Researchers took those answers and noted each respondent's location and the day, month and amount of sun exposure at that location when the person was interviewed.
According to the study, people interviewed during wintertime reported no higher levels of depression than those surveyed in spring, summer and autumn. Even the more than 1,700 subjects with clinical depression reported no particular worsening of their symptoms in winter.
If SAD is not a distinct condition from clinical depression, how has it persisted as a diagnosis for nearly 30 years? The study's authors believe that it may be part of the rhythm of depression, which can come and go over time.
This study will no doubt be controversial, but there is no denying that depression can be crippling, forcing many people to stop working to combat the symptoms.