In many studies, debt has been shown to be a key cause of mental illness.
Linked to this is unemployment; a key cause of isolation is not having a job to go to.
A key cause of this increase was stagnant real incomes, so credit was used to keep living standards constant.
The pressure to remain constantly in touch with managers and colleagues was reported to be a key cause.
Clearly, indifference by state policy makers has been a key cause of the Medicaid abuses in New York.
Federal revenues are at a historically low level and are a key cause of the federal budget deficit.
The EU's "open border" policy, which allowed unrestricted internal migration, was a key cause of concern among voters.
The rise in unit labour costs (see chart) has been a key cause of Italy's chronic lack of growth.
"There is overwhelming evidence that inequality is a key cause of stress, and also exacerbates the stress of coping with material deprivation," the report says.
The two groups referred to date labels as "a key cause of the high and rising rates of waste in the United States".
