4. How many Americans will experience some form of mental disorder in their lifetime? Answer a. One in 20 b. One in 10 c. One in 5 d. About half

1. Interpret the question: The problem asks how many Americans will experience some form of mental disorder during their lifetime. 2. Analyze available data: According to studies in mental health epidemiology, approximately \(50\%\) or about one in every two Americans is estimated to experience a mental disorder at some point in their lifetime. 3. Match with answer choices: - a. One in 20 - b. One in 10 - c. One in 5 - d. About half Given that the data suggests that roughly one in two (i.e., about \(50\%\)) Americans will experience a mental disorder, the correct answer is: \(\boxed{\text{d. About half}}\).