Police are to be given new national guidance on responding to people suffering from mental health issues.
Officers will also be provided with information on handling calls relating to suicide and bereavements.
Authorised professional practice has been compiled by the College of Policing to help forces in England and Wales provide a consistent response to the public regardless of where they live.
It replaces previous guidance published in 2010 and highlights actions that may help officers address the needs of mentally vulnerable individuals.
Inspector Michael Brown, the college's lead on mental health, said: "Mental health affects every area of policing and our aim is to ensure vulnerable people are not unnecessarily criminalised and instead get access to the crisis care they need.
"The new guidance and training is designed to assist officers in identifying vulnerable victims and suspects so they can get the right support.
"Police are not mental health professionals and our aim is to deal with any offences committed and protect the public from harm.
"It will continue to be the responsibility of health and welfare agencies to assist those in mental health crisis."
The guidance states that police cells are not suitable to detain people thought to have mental health problems.
The use of police custody as a "place of safety" for those detained under the Mental Health Act has prompted controversy.
Figures published last month showed the number of times cells in England and Wales are used to hold people suffering mental health crisis has more than halved.
Alison Cobb, of mental health charity Mind, welcomed the publication of new training and guidance by the college.
She said: "Mental health is core police business and that's why it's so important that all policing staff have the knowledge and expertise to help support someone with a mental health problem, including people at their most vulnerable in a mental health crisis and victims of crime."
Dorset Police and Crime Commissioner Martyn Underhill said the new training package "will help ensure consistency across the service and remove postcode lotteries for those with a learning disability or a mental illness."