Whether or not such a person is "cheating" because they may be getting help with harmful emotions seems a very subjective and personal matter which is none of my business. If it helps people to navigate in this world a little better for awhile, where's the harm? And why pass any kind of judgment?
Is it cheating to take a tranquilizer to keep from getting an anxiety attack? Drugs are drugs; some are intended to normalize abnormal behavior. To not use them when they're available and intended to correct a particular behavior pattern would be ignorant.
Jesus taught us that self-mastery is an ideal worth striving for. Those of us who are lucky enough to have this revelation know that true self-mastery is a spiritual achievement which can be had through perseverance, determination, faith, trust, and prayer. But even so, just because a person takes medication to help them through a rough time in their life does not mean that they are failing at self-mastery. Seeking help may, in itself, be evidence of self-mastery. And spiritual work can surely be done even with medication.
How you get to self-mastery not be not the important thing—THAT you get there seems more important."