"Mental health disorders are maybe the most neglected of neglected diseases," said Peter Singer, head of government-funded Grand Challenges Canada.
He said that 75 percent of people with mental disorders around the world, or 350 million, were in developing countries.
"And 85 percent of these people are untreated," Singer told AFP.
The funding will go to support projects in Afghanistan, Belize, Ethiopia, Guyana, Haiti, Kenya, Malawi, Nepal, Nigeria, Pakistan, Sri Lanka, Uganda, Zambia and Zimbabwe.
Several of these countries are war-torn or rebuilding after natural disasters.
Singer said the aid will be used to train specialists, care for children with autism, as well as identify and treat problem drinking, people with dementia and severe post-war mental disorders, and expand global access to online mental health care.
The need is enormous. For comparison, Singer outlined that in Canada there is one psychiatrist available for every 8,000 people, while in Ethiopia one is available for every two million people.
In places like Afghanistan, which has suffered through decades of conflict, an estimated 50 percent of Afghans over 15 years old suffer from depression, anxiety, post-traumatic stress disorder or substance abuse.