Watch: Why Millie Bobbie Brown and David Harbour Both Missed Stranger Things Event in NYCDavid Harbour is sharing how he keeps his mental health right side up. Indeed, the Stranger Things star-who has been open about his experience with bipolar disorder-recently detailed how psychotherapy positively impacted his mental health. "I have been in therapy since I got sober in 1999," David told Future of Personal Health in a recent interview. "When I quit drinking, it forced me to confront a lot of demons that rose to the surface. I was very poor.