OPEN MINDS The Behavioral Health & Social Service Industry Analyst Industry News National Mentor Inc. has been purchased by Boston-based Lifetime Corporation. The purchase price included a four million dollar down payment (four million dollars in cash and one million dollars in Lifetime stock) and a long-term earn-out provision. Mentor, founded in 1983, provides home-based services for individuals with psychiatric disorders, developmental difficulties, substance abuse problems, and head injuries. It has 27 offices in 11 states and projected 1992 revenues of more than $20 million . . .