Chief Constable Gary Roberts says one in five incidents police are called to involve people with mental health issues.
He was giving evidence to Tynwald's Social Affairs Policy Review committee on Friday when he made the claim.
Mr Roberts was asked whether the number of such incidents had fallen after police began working with other agencies.
He said so far there'd been no change, although he did expect the figure to fall in future:
£7.7m cost by Manx Care staff sickness
Manx Care says staff sickness cost it £7.7 million last year.
30.5% hike to rates in Andreas
Andreas Commissioners say rates in their area will rise by more than 30 per cent this year.
Only some war pensions discounted from care charges
Health Minister Claire Christian says only some people on war pensions get them part-excluded when it comes to paying for their care.
Single car crash at Ballacraine
Police say they're dealing with a crash north of Ballacraine at Ballaspur, outside St John's.
Minister releases number of non-toilet trained school starters
Education Minister Daphne Caine says just 22 children who started mainstream education last year weren't toilet trained.
Yellow weather warning for hill snow
Ronaldsway Met Office has issued a yellow warning for hill snow later.
Reconsider cancer sufferer's tree felling application, says commissioner
The Tynwald Commissioner for Administration says the Department of Environment, Food and Agriculture should reconsider refusing to allow a cancer sufferer to fell a tree on their property.
Government asks what you think of drugs
Public Health Isle of Man has launched a survey about people's attitudes towards drugs on the Island.
