A police force attended almost 15 mental health incidents a day last year, figures obtained by the BBC show.
Devon and Cornwall Police has seen a 10% rise in mental health callouts from 4,891 in 2010 to 5,364 in 2014.
The force's police federation said officers were "frustrated that the NHS does not have the capacity to deal" with people with mental health issues.
The NHS said demand for services had risen, creating "pressure". The force refused to comment.
In November, a teenage girl with mental health problems was kept in police cells in Devon for two days because of a lack of care beds.
NHS England has since apologised and described her care as "unacceptable".
http://www.bbc.co.uk/news/uk-england-devon-31954293