A dozen years ago, Edward C. Donovan was a cop on a steep downhill slide.

The nightmare pressures of a Boston patrolman's life were mounting -- "riots, protests . . . little children burned to death. It's sickening. You go around a corner and cry. I got hardened to it, but I never got used to it. I'd take anti-anxiety pills.

"I was your average real cop. I rushed people to hospitals. I've gone into burning buildings. The boring calls. The standing in blood. The uncertainty.

"You can do everything right for 15 years and then in a split-second decision, you can mess up once, and you're in trouble. There's always that pressure."

Besides popping pills, Donovan took to heavy drinking. Ultimately, thoughts of suicide crept in.

"I put a gun to my head more than once," says Donovan, then a 12-year veteran of the force, in his late thirties with a wife and seven children. "I took my cruiser and aimed it at a tree, but I pulled out at the last minute."

Knowing then that he was about to hit bottom, "I asked for help."

For a policeman raised on the Hollywood image of the strong, silent cop able to handle anything, conceding frailty was one of the hardest things he ever did. To shatter the macho dark-blue uniform and side-holster facade would be unmanly, he thought, even while inside his guts trembled at what the next call on the car radio might bring.

Speaking up, however, turned out to be "the biggest favor I did for myself." He has subsequently become internationally known in the law-enforcement world for his work in counseling other police officers, encouraging them to voice their fears--as a way of easing them.

Still holding the rank of patrolman on the Boston force, Donovan, now 50, is director of that department's Police Stress Program; president of the International Law Enforcement Stress Society (which he formed); founding editor of "Police Stress," a quarterly journal that goes out to police agencies around the world, and a board member of the American Institute of Stress. Even the license plate on his battered Ford LTD reads "STRESS."

Once over the hurdle of asking for help, Donovan had himself admitted to an alcoholism recovery program, where he became aware of how major a role police stress -- and his inability to deal with it -- had played in his descent into alcoholism. He became interested in the research of stress expert Hans Selye of Montreal, and later studied under him.

Donovan -- "I'm in my 13th year of sobriety" -- became convinced that the kind of peer counseling and group meetings practiced by Alcoholics Anonymous would be valuable in treating other officers, "a cop helping a cop." This idea led to the formation in 1973 of the stress unit, one of the first of its kind in the nation. About 100 police departments, including several in the Washington area, now have stress programs.

"We knew a lot of hurting police officers who wouldn't go for outside help, who wouldn't go to a shrink."

Donovan has been invited to lecture on police stress by Harvard, Notre Dame, the FBI, the Secret Service and the International Chiefs of Police Association. He will be the keynote speaker tomorrow at a men's-issues conference on Long Island (cosponsored by the Coalition of Free Men and Adelphi University), where the topic is "Freeing Men for Healthier Life Styles."

That, of course, is the theme of Donovan's new life. Stress can be "a killer," and he is hard put to think of another profession more stressful than police work.

"The public's expectation of a cop," he has written, "requires that he be all things to all people -- a police officer, doctor, lawyer, judge, juror, psychiatrist, social worker, ambulance driver, plumber, veterinarian, locksmith and every other occupation in the public domain. It is an impossible demand.

"A cop is never off duty. He's paid to look for trouble -- to look for the negative in people. It causes trouble in marriages."

As the internal tensions mount, a great many police officers, Donovan has found, have no safety-release valve. The result is that as a profession police work ranks high in depression, domestic strife, alcoholism and suicide.

For many, he believes, the blame can be laid on the "male macho mystique."

"Did you ever see a cop approach a car he has stopped?" he asks. "He looks like a 10-foot gladiator. You don't know underneath he's a pussycat or a troubled man."

As a red-haired rookie (5-9, 135 pounds) he used to ask himself, "Who's ascared of me?"

The macho cop sees inner fears as a sign of weakness and tries to hide them not only from the public, but from colleagues. But, insists Donovan, there is nothing to be ashamed of. "Those teen-agers are testing you--it's scary."

Not, of course, that he believes cops shouldn't project authority. But they should know when "to take off that armor -- to be human." The focus of the Boston program is on getting the officer to open up -- to "ventilate."

The "No. 1 thing I tell them," says Donovan, "if something is bothering you, you've got to talk to someone."

Donovan operates out of a ramshackle white-frame cottage on the grounds of a city hospital at the edge of South Boston. The site was picked deliberately to isolate it from police headquarters.

The last thing a macho cop wants his cronies to know, says Donovan, is that he has sought help from the stress program. If an officer requests it, Donovan or one of his 30 volunteer counselors -- all members of the force -- will meet him or her in a car, bar or any other place of the officer's choice. Donovan wears civilian clothes -- typically jeans and a sports shirt -- to separate himself from department officialdom.

"Hey, are you thinking of 'swallowing' your gun?" Donovan asked a policeman recently, and then related his own contemplation of suicide. "That was his innermost secret, and here I was this guy admitting to it myself."

Not infrequently, a policeman will start crying. "I say, 'It's all right to cry. That's why we've got the tissue right there.' "

Beyond individual counseling, there are weekly "rap" sessions in which newcomers are encouraged to exchange insights into problems. Like AA, there's even a meeting for spouses, who experience their own fears and frustrations about police work: the odd hours, danger, wear and tear on family life. "We never," says Donovan, "treat an officer without the spouse."

Like many policemen, one older officer in the program had so played the macho role that he was overly strict and protective of his children. His 23-year-old son had refused to invite him to his wedding. In the rap sessions, colleagues told him in no uncertain terms he had been "making an ass of himself" (a "tough-love" tactic, says Donovan). Getting it from his peers, the officer accepted advice on behaving more positively toward his family. In time, he won back his son's friendship.

A major emphasis is counseling police officers who have killed in the line of duty. "It's not like a war with an unseen enemy -- he will read about this in the paper the next morning," says Donovan. "The ramifications of a shooting last for years. The officer begins to wonder if he could have done it differently. It takes a toll. The minute a cop is in a crisis, we get paged."

Police officers are encouraged to develop outside interests to help alleviate pressures, and to socialize with "positive people" in other lines of work. Simply rediscovering that the world has good people, claims Donovan, can be a morale booster.

About 900 Boston police officers -- in a current force of about 2,300 -- have participated in the stress program, and all new recruits get a stress seminar.

Those who have been involved, believes Donovan, become better people -- on the job and at home. "When they are in touch with their stress, they are better able to deal with it." Instead of quitting, "they're back on the streets."

Like himself, most cops come on the job "with all your altruistic goals, "wanting to do good." What they get is "a love/hate job. You love police work, but you don't like what it's doing to you."

Patrolman Donovan is trying to modify that equation.