VANCOUVER -- The BC Coroners Service says completed investigations of 872 overdose fatalities show more than half of those who died had been diagnosed with a mental health disorder or had evidence of being mentally ill.

The investigations represent about a third of the 2,545 overdose deaths in 2016 and 2017, the service said Thursday after releasing the report.

Chief coroner Lisa Lapointe said 80 per cent of the people in the completed investigations had contact with health services in the year before they died and when it comes to mental health, it's clear only a "hodgepodge" of services are available in B.C.

"We know from speaking with families of those who died that many times families are beside themselves trying to find help for their loved ones and trying to find help perhaps in that window of opportunity where the individual is looking for help or willing to accept help. To date it's been very challenging and it still is in this province for families to find evidence-based recovery."

Lapointe said it's "tragic" that British Columbia is still seeing an average of 121 overdose deaths every month.

British Columbia's mental health and addictions minister, Judy Darcy, was not available for an interview.

Fardous Hosseiny, national director of research and public policy at the Canadian Mental Health Association, said mental health and addiction often go hand in hand when people suffering from mild to moderate anxiety or depression start self medicating with potentially deadly substances while on a wait list for services beyond their family doctor's office.

He said one in five Canadians deal with a mental illness every year but a lack of integrated services between family doctors, psychiatrists, social workers and peer-support workers means the patients' condition can worsen to a point that it becomes a serious disability.

Federal funding allocated specifically for community mental health services is needed but Canada invests the least amount of money compared with other G7 countries, Hosseiny said.

"I think that would address dealing with this opioid crisis because a lot of it is people numbing their psychological suffering, maybe due to violence, trauma, colonialization, racism, whatever it may be."

Last week, the Canadian Mental Health Association called on the federal government to introduce a so-called mental health parity act, similar to legislation in the United Kingdom, for example, to value treatment for mental health equally with physical health.

"What we know is that there are 1.6 million Canadians with unmet mental health needs each year," Hosseiny said.

The report from the Coroners Service said more than two-thirds of those who fatally overdosed used drugs alone and 45 per cent of those who died had reported pain-related issues.

It said 63 per cent of the deaths occurred in homes, but that number shot to 74 per cent in the Fraser Health authority, the largest of the six health regions that serve the province.

The report says most of those who died were men between the ages of 30 and 49 but women were more likely to use injection as a way to consume drugs versus smoking, snorting or ingesting them.

Illicit fentanyl was the most commonly detected street drug, especially in deaths among those aged 15 to 29, the report says, adding more than half the victims worked in the trades and transport industries.

The Coroners Service has recorded over 3,400 deaths since January 2016 as part of a crisis fuelled by the opioid fentanyl but it says the number of fatalities decreased by 27 per cent this August compared with July.

The top four drugs involved in illicit-drug deaths were fentanyl, cocaine, methamphetamine and heroin.