The doctor is on. Harold Kaufman, the well-known Washington psychiatrist, is back on the bandstand, leading Monday night jam sessions at Charlie's, Georgetown. The pianist is perhaps best remembered for his tiny but always active Dupont Circle jazz club, the Rogue and Jar. It closed several years ago, permitting Kaufman to concentrate on his psychiatric practice without the full-time responsibility of running a club and restaurant.

The Charlie's jam offers a bridge between work and hobby for Kaufman. "Jazz music is spontaneous improvisation, and what goes on in psychiatric sessions is usually spontaneous and improvised," Kaufman says. "One medium happens to be verbal, the other musical. I find myself quite comfortable with a situation where there is structure but there is pre-form within that structure. The process is similar -- you have an idea of where you're going but you don't know what's going to happen until it happens."

Among the fine Washington musicians who have shown up so far: Buck Hill, Shirley Horn, Ron Elliston, Bill Glaser and Marshall Keys. "We try to keep it spontaneous and unrehearsed," Kaufman says. "When we get rolling, the only breaks are when people get off the stage and others get on."