Lodestar by Phyllis Horn
1991, Paperback

Therapist Stephanie Scott and Judge Alice Cutter have enough problems with vicious threats to their lives because of a child custody case decided in favour of a lesbian mother.

Now Stephanie's ex-lover has come to her because Stephanie's replacement is being terrorized by mysterious phone calls. And Alice's son and his family have vanished into a commune named Enlightenment, where a chemical compound named Lodestar, unique to the Enlightenment commune's land, has turned its residents into compliant robots.