AUGUSTA, Maine (NEWS CENTER) — People working in both the mental health and substance abuse fields say there is growing belief that a majority of opiate drug addicts also have an underlying mental health problem, such as depression or other conditions.

They say that problem needs to be treated along with the addiction in order to have a successful recovery.

Cumberland County Sheriff Kevin Joyce said he sees the evidence of co-occurring disorders among many of the inmates in the county jail.

» RELATED: National expert wants more attention on prescription drugs to fight addiction

The conference attendees even talked about changing the words to describe the addiction, saying the term should be "substance use disorder," instead of "substance abuse."

They say that would reflect the fact that many addictions are caused, or made worse by the accompanying mental health condition.