In its latest survey, the WHO found demand for mental health services was increasing as problems with bereavement, isolation, loss of income and fear mounted.
Mental health services in the region were chronically underfunded before the pandemic, it said, with less than 2 percent of national health budgets allocated to the sector.
But now, things had gotten worse, with most countries recording an increase in need and a severe disruption to what limited services are offered.
The WHO also said it was noticing increased levels of drug and alcohol use, and people were also likely experiencing more insomnia and anxiety.
It said governments should be allocating resources to mental health as an integral component of the responses to the Covid-19 pandemic.