Drug refers to a pattern of continuing substance use despite cognitive, behavioral, and physical symptoms.

Drug addiction / abuse reffers to a pattern of continuing substance use despite cognivite, behavioral and physical symptoms.

This can also be called susbtance use disorder. This disorder affects a person's brain and behavior due to the continuos and abusive using of the substance. The constant use makes the person incapable of self-control. It may affect its reasoning and behavior would be the consequences. Physical symptoms would be mostly the cause, in this case.

uhh idk for sure but i think it makes it difficult to pump the oil through the oil rigs