If the Gospel is true then we don’t have to numb ourselves to our problems because there is real healing and real rest for our pain.
There are a number of reasons that people might be interested in doing drugs. Perhaps, they feel like it might relax them, or give them extra focus, or to get others to like them. But regardless of the specifics of the situation, the choice to use drugs is usually rooted in trying to overcome some sort of pain. The problem with trying to overcome discomfort with substances is this can easily cause an addiction. But we as Christians know that our hope and rest comes from the Lord.