In the last ten years of his life, John F. Kennedy suffered from Addison's disease, a disorder in which the adrenal glands fail to produce the hormone cortisol, which helps the body respond to stress. While JFK denied allegations that he had the disease, one of its side effects was to give him a bronzed glow, which may have helped him look healthy in TV debates against Richard Nixon. JFK was taking the drug cortisone to treat the disease; the possibility is examined that he may have been overdosing on this drug, causing increased anxiety, panic attacks, insomnia and an increased sex drive. JFK also suffered from chronic back pain for which he took painkillers. ""Dr. Feelgood"" Max Jacobsen supplied JFK with amphetamines, but claimed they were vitamins, hormones and enzymes. Drug addiction may have played a role in the Cuban missile crisis, JFK's rumored infidelity, and even his own assassination.