Doctor Su Tung-ping conducted a study at Taipei's Veterans General Hospital of more than 100 cases of insomnia. He discovered that one-third were primary insomnia, one-third were secondary, and one-third were a mix of primary and secondary insomnia.
榮總精神部主任蘇東平針對台北榮總一百多個失眠個案研究發現，原發性失眠、續發性失眠、原發性混合續發性失眠各佔三分之一。