Drug use does not make a person lesser; irresponsible drug use does. There are a number of holistic, naturally occurring drugs that can be used responsibly and to useful effects by those who have a healthy amount of respect for them. Responsible drug use requires intelligence, awareness and good decision making, which highly intelligent people normally possess. The commonly observed traits of a responsible drug user are that they use experimentally, objectively and with restraint.
Not everyone uses drugs experimentally. This term is used mistakenly in many situations. Many people use drugs because of peer pressure, and others yet try drugs simply because they are bored. To legitimately use drugs experimentally indicates a particular level of intelligence. Experimentation, in the truest sense of the word, means you are using drugs in order to learn, putting yourself in the role of test subject. This is a trait of genius drug users.
Objectivity in drug use is another important way of approaching drug use like a genius does. Brilliant minds use drugs so long as they are increasing their intellect and perspective. The people who give drug use a bad name do so in part by using drugs for mere entertainment, or because they have become dependent on them. A brilliant mind is self aware and objective enough to recognize when this is beginning to happen to it, and will initiate restraint. People of high intelligence do not expect to be able to control the effects of a mind-altering drug. Instead, they experiment with them objectively and respond to them according to the effects that they have on them.
Lastly, a brilliant mind only uses drugs to the extent that they are useful to them. Drugs are highly unpredictable. They are known to effect different people in very different ways. A mind altering drug can have one type of effect on one person and a completely different type of effect on another. Highly intelligent people monitor their own reactions to drugs in order to understand how to use it, or how to discontinue it. For some, this may mean heavy use and for others it may mean sporadic use.