Most drugs can be used intelligently to improve your life. The issue is the way people use them is often another manifestation of the poor life choices and external factors that got them in trouble in the first place.

If you use drugs to face your life challenges, that can be good. If you use drugs to escape, that is almost always bad. With addictive drugs, it takes discipline and a positive environment to use them responsibly. But of course, it's often the case that a lack of discipline and an environment full of pain leads one to use such drugs in the first place. So it's a recipe for disaster.

For example, alcohol. Alcohol lowers inhibitions. It's good to help people socialize on occasion. You can make great, lifelong friends that way. But if you use alcohol to escape your life, you're in trouble. In the first place, you're using up time that could be used productively to fix your problems. But of course, alcohol is also highly addictive and poisonous. So you're adding to your problems.