There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
He made his money in mining and is the 442th richest person in the world. His money is the result of purchasing of low-producing gold mine shafts in 1994, which he made profitable. Since then, he has built African Rainbow Minerals, benefiting as a result of South Africaâs Black Economic Empowerment (BEE) laws.