Substance abuse is often a cause of homelessness. Addictive disorders disrupt relationships with family and friends and often cause people to lose their jobs. For people who are already struggling to pay their bills, the onset or exacerbation of an addiction may cause them to lose their housing. A 2008 survey by the United States Conference of Mayors asked 25 cities for their top three causes of homelessness. Substance abuse was the single largest cause of homelessness for single adults (reported by 68% of cities). Substance abuse was also mentioned by 12% of cities as one of the top three causes of homelessness for families. According to Didenko and Pankratz (2007), two-thirds of homeless people report that drugs and/or alcohol were a major reason for their becoming homeless.