Abu Zayd al-Balkhi

Abu Zayd Ahmed ibn Sahl Balkhi was a Persian Muslim polymath: a geographer, mathematician, physician, psychologist and scientist. Born in 850 CE in Shamistiyan, in the province of Balkh, Greater Khorasan, he was a disciple of al-Kindi. He also founded the "Balkhī school" of terrestrial mapping in Baghdad. Al-Balkhi is believed to have been one of the earliest to diagnose that mental illness can have psychological and physiological causes and he was the first to typify four types of emotional disorders: fear and anxiety; anger and aggression; sadness and depression; and obsessions.