What is meant by the statement “it was once thought that substance use disorders were self-limiting?”

What is meant by the statement “it was once thought that substance use disorders were self-limiting?”

Options:

A. That there were limited treatment options for people with an SUD
B. That only recreational drugs could be attached to a diagnoses of an SUD
C. That it is very easy to diagnose an SUD because there are few specific symptoms
D. That those with an SUD would have a shorter-than-average lifespan

Correct answer is option D. That those with an SUD would have a shorter-than-average lifespan.