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.
Tony Elumelu is a revered business man with investments in ventures including Transcorp, and real estate across Nigeria. He has a net worth of $ 1 billion and was ranked Forbes 26th richest African man in 2014. He owns major stock in the United Bank for Africa (UBA).