Determining the nature of the relationship between cognitive impairment and the prolonged use of amphetamines can be difficult because

Question

A) amphetamines don't actually cause brain damage.
B) people taking amphetamines refuse to be tested.
C) researchers cannot determine the cause-and-effect relationship between cognitive impairment and amphetamine use from correlational data.
D) there are no known long term risks associated with these drugs.

Answer 1

Answer: C
Rationale: People who abuse drugs such as methamphetamine and ecstasy rarely just use one drug. Most users also abuse other drugs such as marijuana, alcohol, and possibly other stimulants. Thus, it may be these other drugs, or their combination, that accounts for any observe cognitive impairments and brain damage. Also, damaged nerve cells and other neurological problems are not necessarily the consequences of drug use. The relationship may go the other way around—people with certain types of neurological problems may be more likely to abuse drugs.