A、Mental disease. B、Poor health. C、Stress. D、Depression. D文章末尾处提到，抑郁症影响着大约六百万年龄超过65岁的美国人，或者说约占总数的15％。抑郁症被认为是造成老年人高自杀率的最大原因。因此老年人

(16)Movies often depict the elderly as ill-tempered. In fact, most elder people have fewer negative feelings, like anger, than the young.
    Recent research into how emotions change with age may be able to help people lead healthier and longer lives and bring about new treatments for depression in the elderly.
    Like people’s bodies, emotions change over time. Older people for the most part have far fewer negative feelings, such as worry and stress, than do younger people, studies show.
     (17)The elderly learn to free themselves from feelings of negativity and seem to focus more on present situations that bring pleasure, rather than on the future, researchers say. They also tend to process negative information less deeply than positive information.
     (18)By contrast, positive feelings such as enjoyment and happiness change very little from the time a person is in his youth until old age.
    " It seems to be essential for our emotional well-being to not look back in anger and to focus on the positive when we are older," Stefanie Brassen, a researcher at the University Medical Center Hamburg-Eppendorf, said in an email.
    Older people who are depressed seem not to use the sort of emotional regulation typically seen in the elderly, researchers say.(19)Depression affects some six million Americans over the age of 65, or about 15% of the total, and is believed to be a big reason why the elderly have the highest suicide rate, according to the nonprofit Geriatric Mental Health Foundation.
    In a potential new treatment approach, Dr. Brassen and colleagues are developing a training program in which older people practice strategies to better adapt to life circumstances.
16. How are the old like in the movies?
17. According to researchers, what do the old pay more attention to?
18. What will change less over time when a person is getting old?
19. What is an important reason for the highest suicide rate in the elderly?