Can you match each of these photos to each corresponding pathway by which substance use can become a use disorder? The three pathways are: (1) the psychoactive component is a side effect of a medication taken to treat a medical problem; (2) through environmental exposure; (3) setting out to use a substance for its psychoactive effects. Answer: Matching the photos to the pathway, from left to right: A-2, B-1, C-3.