"The therapy of an addict," says Dr. Lawrence Hatterer, "always depends on a helper."

This person may be a mental-health professional, or a friend, relative, co-worker or peer addict.

He or she should be able to "keep (the addict's) confidences, have a strong ego and the capacity to tolerate other people's anxieties, depressions and emotion blackmail . . . without always expecting a proportional return."

Former addicts often make the best helpers, says Dr. Hatterer, since "It is essential that the helper understand the addictive process. A peer-addict knows how to be tough with peers."

Those who can't see limits for themselves, or who set unattainable goals for an addict, he warns, will not make good helpers. Before agreeing to become a helper, a person should become familiar with the responsibilities, and be aware of the difficulties and limitations.

"Modest goals are safe and most realistic," he says. "(The helper) must know which addicts will never be capable of overcoming the process and require life-long support or custodial care."

Among peer-addict self-help groups Hatterer lists:

Alcohol: Alcoholics Anonymous (Alanon/Alateen) 244-2274.

Gambling: Gamblers Anonymous, National Service Office, P.O. Box 17173, Los Angeles, Calif. 90017.

Drugs: Pills Anonymous (pills and other mood-altering drugs) P.O. Box 473, Ansonia Station, New York, N.Y. 10023, (212) 847-0700.

Food: Weight Watchers International Inc., 800 Community Dr., Manhassat, N.Y., 11030. Washington, D.C. office, 770-4115.