Final answer:
The statement about SAD that is not true is that full remission of symptoms at other times of the year is not necessary for diagnosis. SAD is linked with seasonal changes and responds well to light therapy, which helps regulate melatonin production.
Step-by-step explanation:
Understanding Seasonal Affective Disorder (SAD)
Seasonal affective disorder (SAD) is a type of depression that typically occurs during the fall and winter months, when daylight hours are shorter. The statement that is not true with respect to SAD is: "It is not necessary to have full remission of symptoms at other times of the year to make this diagnosis." The Diagnostic and Statistical Manual of Mental Disorders (DSM) does require periods of remission at other times of the year for the diagnosis of depression with a seasonal pattern. Patients with SAD often respond well to light therapy, and indeed, the "with seasonal pattern" specifier can be applied to bipolar I, bipolar II, and major depressive disorders. SAD does involve a regular temporal relationship between the onset of symptoms and the time of year, and a person must demonstrate at least two depressive episodes at the same time of year to make the diagnosis of SAD.
Regarding the role of melatonin, it is proposed that individuals with SAD may produce too much melatonin when the days are shorter and darker, leading to the symptoms of increased appetite, sluggishness, and increased sleepiness. A possible non-drug therapy for SAD is light therapy, which can help regulate melatonin production and alleviate symptoms.