Conventional wisdom long held that you couldn't help an alcoholic until the alcoholic wanted to be helped.

The premise of intervention is that such conventional wisdom is dangerous bunk.

Intervention is "not all that mystical and mysterious," said Lois Chatham, director of basic research for the National Institute on Alcoholism and Alcohol Abuse. "It's about breaking down denial."

Interveners may include a spouse, child, sibling, parent, boss, friend, co-worker or neighbor -- anyone who has emotional clout with the alcoholic. They surprise the alcoholic in a prearranged setting where they can sit in a close circle and speak directly, one by one. Using prepared notes if necessary, each intervener recounts specific instances where the alcoholic has embarrassed, frightened or endangered them by excessive drinking.

Often the format is a list of bad memories:

"You were two hours late for dinner Tuesday, and I was terrified because I knew you had been drinking."

"At the party last Friday, I was humiliated because you passed out with your face in the soup."

"You promised to help me with my homework, but then when you got home you just kept on drinking and you got madder and madder."

Interventions must be carefully planned and thought out, said Babette Wise, social worker in the alcohol-drug program at Georgetown University Medical Center. "A family running in and confronting a relative on their own usually doesn't work."

In rehearsals and role-playing sessions supervised by trained counselors, participants learn to anticipate the alcoholic's excuses, denials and protests. They stick fast to their demand that the alcoholic seek professional treatment immediately -- not next week, not tomorrow, but today.

Usually they have a car ready, and sometimes even a suitcase packed.

The statements to the alcoholic must be made calmly and without malice, said Sandy Clunies, director of community relations for the Seneca Melwood Treatment Centers in Montgomery County. But they must be honest and specific enough to pierce what she calls "the sincere delusion" that envelops alcoholics and the "enablers" around them.

Simply reasoning with an alcoholic is not enough, said Scott McMillin, director of the addiction treatment center at Suburban Hospital in Bethesda, because many alcoholics and drug addicts build up so much denial that they won't believe the facts about their own problem.

"And the family may have trained them not to listen by going back on their word so many times," McMillin said.

The format of an intervention cuts against natural familial instincts: It requires planning behind the alcoholic's back and relies on a rehearsed all-or-nothing confrontation rather than a conversational give-and-take.

Hardest of all, interveners must be prepared to draw a high-stakes bottom line -- and stick to it -- if the person won't seek immediate help. A spouse may threaten to leave, a boss may threaten a layoff, children may threaten to stop covering up for Dad.

But it's not a ganging-up to humiliate the alcoholic, and in most interventions the person agrees to treatment without the need for any bottom-line threats.

Proponents say they know from experience that in a field littered with depressing statistics, intervention can succeed. "We don't have research proving that it works," said NIAAA's Chatham, "but the clinical wisdom is that it does."