Police Scotland officers and staff suffering psychological problems took nearly 200,000 sick days over the last three years, new figures show.
The force said mental health issues resulted in 141,230 lost days among front-line officers.
The Liberal Democrats said the figures showed evidence of a force “being stretched to breaking point”.
The Scottish government said the welfare of officers and support staff was taken “very seriously”.
Police Scotland released the figures to the Lib Dems under Freedom of Information laws.
The party’s justice spokesman Liam McArthur said police officers and civilian staff were not getting the support they needed from the Scottish government.
He said: “The savings that were promised by the SNP before the creation of Police Scotland have not materialised.
“As a result, officers and civilian staff are being asked to do more and more with less. With the chief constable warning that further cuts are coming, the pressure on staff is only likely to get worse.”
He added: “We have already seen staff surveys which show morale is at rock bottom. The shortages are affecting the health of officers and civilian staff and these new figures are a huge concern.
“Policing is a high-stress profession at the best of times. The changes that the SNP forced through are stretching the mental health of officers and civilian staff to breaking point.
“This means giving police management the freedom to put resources where they are needed.
“Extra money is also required to plug the hole in the national force’s budget and avert the loss of staff which would only put those remaining further under the cosh.”
A Scottish government spokesman said Police Scotland would be expected to have “robust policies” in place to support staff and manage their health at work.
The spokesman added: “They have a number of targeted activities to support wellbeing and occupational health across the organisation.
“We have committed to protecting the police revenue budget in real terms, safeguarding policing from Westminster budget cuts and delivering an additional £100m of investment by the end of this parliament, in addition to £55m of reform funding in 2016-17.”