Very, very few people truly have no options other than porn. But I'm sure many people have convinced themselves they don't since they can content themselves with porn.

Regardless, it's a feedback loop. People who deal with depression/anxiety are more likely to develop drug addictions. A "normal" person can usually try a given drug once and be fine. Someone with a predisposition to addiction can't do the same.

Likewise a lot of people can casually use porn without much of an issue, but some people allow their consumption to develop into an addiction that negatively impact their life.