Theophanes, a monk (752-817), wrote in his Chronography that Muhammad suffered from epilepsy. From that time most historians repeated this opinion. When in the late 19th century better notions of psychopathology became common, this diagnosis was challenged. Some thought his disease was hysteria or hystero-epilepsy, although for most scientists epilepsy was excluded. There was no definitive answer to this question. A better scientific examination of the sources has made clear that all symptoms of acromegaly are present with some psychopathological paranoid traits. Acromegaly is caused by a small tumour of the hypophysis, beginning most of the time about the fortieth year and ending in the sixtieth year with an apoplexy of the hypophysis.According to the hadith Muhammad suffered from a long-lasting disease, which he treated by means of bleeding. He walked as somebody who comes down from a hill. His skin-colour was peculiar, not white, not too tanned, somewhat rosy. His eyebrows were conspicuous. He was sweating heavily, especially when he was receiving revelations. He heard the noise of bells and voices. He had a great appetite and suffered from hunger. Notwithstanding his sexual relations with ten young women, he remained quasi-sterile: one only child after the age of forty years. During his last illness he suffered from intense headaches, losses of consciousness, back- and intestinal pains.
He died at the age of 62 years. Psychologically he was known as trustworthy, somewhat retiring and prude. Initially, about at the age of forty years, he was depressed, retiring, and showed a tendency to suicide. He spoke slowly. Most typical were his great hands, dough feeling palms, great feet, a long fleshy nose, well developed ears and a peculiar voice.These indications suggest that he suffered from acromegaly. This hypothesis allows to explain almost all details found in the hadith.Acromegaly is caused by an adenoma of the pituitary, which causes an increase in growth hormone (somatotropine) and usually a deficiency or increase of other hormones such as gonadotropine. The disease begins in adult persons about the fourth decade of age. Most patients die about the age of 60 years. It is a long-lasting disease with slow progress, sometimes burning out. Most patients tolerate it reasonably well. The melanophore hormones secreted by the pituitary cause a peculiar straw-yellow skin-colour. Excessive sweating is sometimes caused by hyperthyroidism. Sweating can be oily and have an unpleasant odour. Patients suffer from high blood pressure. Some hirsutism is observed (eyebrows). The growth of all extremities after adult age causes also the vertebrae to extend and the spine to curve. This extension can cause pain as the nerves suffer pressure.