Whatever we consume now will affect our body system at old age and that's why we should be careful not to take in substances that will have side effects on our body at old age. A little alcohol is good for the stomach but beware of hard drugs and live responsible. I have seen people who went insane dhe to taking drugs that's very strong for their brain to contain.
Exactly taking in any substance apart from food can affect our body system at old age, both alcohol and drug affect our body system, internally and externally, it's also affects someone mentally and physically. Just because alcohol is a social acceptable drug doesn't make it good for our health. if it is going to add any good to our body system it will not be socially acceptable drug, rather it will be medical drug. As a human being we are allow to take two things through our mouth to the stomach :
1: food or Nutrients
2: Drug (medical drugs)
1: food is any substance that is solid or liquid, which when taken is digested and assimilated in the body to provide energy to the body and it protect the body against diseases.
2: Drug is any chemical substances which when taken, it changes the behavior of the person or function of the body.
We should not be confuse about the definition of drug that I made. There are medical drugs that we take in. they are also socially acceptable drugs that some people takes, and they are also illegal drugs that some people takes.
*Medical drugs*: medical drugs are drugs that will take with the prescription of a doctor or pharmacy when you we are sick or ill to feel better again. E.g paracetamol, and so on. It changes the function of the body, from sickness to healthy.
*Socially acceptable drugs*: are drugs that is not prevented neither is accepted, and a victim of it will be not be arrested for taking them but it is harmful to the body. E.g Alcohol, colanut, cigarette and so on.
*illegal drugs or hard drugs*: are drugs that are unacceptable or unlawful and a victim of it we be arrested and face the consequences. Because they are really harmful to the body system, physically, mentally and psychologically. E.g cocaine, Marijuana and so on. It changes the behavior of a person, from well-behaved to abnormal behavior.
But I know that OP is taking about hard drugs, which is very harmful to human systems which lead to distroying the person life and feature. Some people abuses medical drugs. Some are addicted to hard drugs and socially acceptable drugs. Which is not proper, because they may damage and destroy some parts of the body system. So, I advise my fellow brothers and sisters in this forum that are involved in any of this, should stop. So that we should maintain our health, because health is wealth. We need to prioritize our health, to secure a better future.