What has been demonstrated in epidemiological studies of psychological disorders

Question

Quizplus · Accepted Answer

Epidemiological studies have consistently found that psychological disorders are more common than many people realize. For example, it is estimated that 1 in 5 people in the US will experience a mental illness in any given year, and that roughly 1 in 25 people are living with a serious mental illness. These rates demonstrate that mental illness is a significant public health concern.

The other options can be ruled out:
A) is not true, as the prevalence rates of mental illness have actually been increasing in Canada in recent years.
C) is not true, as epidemics involving psychological disorders are not common. 
D) is not true, as lifetime prevalence rates are generally higher than standard prevalence rates, which typically cover a shorter time frame.

What Has Been Demonstrated in Epidemiological Studies of Psychological Disorders