請依下文回答第 46 題至第 50 題： When he moved from South Africa to New York City, Norman Rosenthal, a psychiatrist, noticed he felt moredepressed during the cold, short days of the city’s winters than he had in his home country. Years later, he publishedthe first paper to scientifically name the winter blues: Seasonal Affective Disorder (SAD). Subsequent studies havefound that the seasonal depression affects those in northern latitudes more and that about 10 percent of SADsufferers have symptoms in the summertime instead. The most commonly reported symptoms of winter depression are hypersomnia, the desire to sleep more thanusual, as well as an increased appetite and lack of interest in things. According to experts, most people experiencesymptoms in young adulthood, but SAD can begin at any stage of life. The condition also varies by sex. About threetimes as many women as men get SAD. But why does less daylight make some people clinically depressed? One leading theory is that the change indaylight disrupts our bodies' release of melatonin, a hormone the brain releases every night to promote sleep. As thesupply of daylight dwindles in winter, melatonin may wear off later. That means in the morning the body is still ina state of biological night. As for summer SAD, triggers might include the heat and humidity. Instead of feelinglethargic, summer SAD patients more often feel irritable and agitated. Experts say a professional diagnosis is a crucial first step toward treatment and self-diagnosis is not suggested.One common treatment is sitting in front of a bright box of light for 30 minutes to signal to the body that it’s timeto wake up. But the drawback to light boxes is that they only work on the day that you use them, so you need to usethem daily. Another treatment that may have longer lasting benefits is Cognitive Behavioral Therapy (CBT), a formof talk therapy. As negative thinking tends to breed negative emotions, CBT aims to encourage more neutralthoughts. For example, “I hate winter” might be reframed as “winter isn’t my favorite season, but I still find thingsto enjoy.” Moreover, finding wintertime hobbies may also help. People with SAD often have hobbies that aresummer specific, such as growing gardens or beach going. Instead of hibernating under a blanket, people areencouraged to find indoor hobbies, such as knitting, reading, or going to the gym, to boost their mood. Whetherusing light or talk therapy, there is no reason to not seek mental health treatment, even if symptoms are only presentfor a few months out of the year.
According to the passage, what prompted Norman Rosenthal to study seasonal depression?
