EARLY THIS spring, Jerry Finley started acting in a way the text books describe as "socially inappropriate." Dressed in a secondhand pin-striped suit, red bow tie and sneakers, he approached women on the street saying, "Will you have sex with me?" Worse still, he subjected them to bizarre fantasies, the kind most of us have but know not to say aloud. It was embarrassing. Clearly, such offbeat behavior couldn't continue. Stopping it, however, was another matter.

Outlandish sexual advances were not part of Jerry Finley's medical profile. On the contrary, somewhere in the course of his 52 years he had learned to equate sex with the wrath of God. It probably happened way back in Tennessee when, as a 2-year-old boy, he was placed in an institution run by nuns because no one else wanted him. "If you look at a woman it's a sin," he would mutter angrily under his breath, his eyes transfixed on some distant point on the ceiling. Until now, he had been firmly convinced his destiny was Hell. "I'm nothing but a no good good-for-nothing," he told everyone on the days he was talking.

There is a long medical name for what's wrong with Jerry. It has to do with not preceiving reality like the rest of us. Jerry says he's just plain "crazy," blaming his scrambled mind alternately on the devil, the Roman Catholic Church and the electric shock treatment once administered to jolt him out of depression. Jerry had been depressed ever since he could remember. Periodically, he saw extraordinary pictures in his head and listened to voices no one else could hear.

Eighteen months ago Jerry entered a program where former mental patients learn to operate in a world that regards them with suspicion and fear.

Here the social workers possessed the kind of inspired love and dedication not learned in graduate school. They became the parents Jerry Finley never had, getting him to change his grimy, food-stained black trousers, gently teaching him that society prefers him clean to dirty, suggesting he shave once in a while.

The staff believed in responsibility, too - something mental patients learn to avoid in institutions - and encouraged Jerry to do chores around the building. At first he was on the ash tray emptying detail. Later he graduated to collecting dirty coffee cups and washing them. story continuing just continuing the article.

Later he graduated to collecting dirty coffee cups and washing them. Finally, last summer he got his first outside job - sticking labels on packages for a retail chain. "I earned a lot of money he said proudly, pulling four $20 bills out of his pocket, the first earnings of his 52 years.

At last, Jerry Finley was beginning to act more like the rest of us. At least, so everyone believed, until the "socially inappropriate" incidents.

If truth be known, Jerry's two special counselors at the center were secretly delighted by the embarrassing sexual advances. After all, wasn't such "socially inappropriate" behavior an affirmation of life? After years of depression, repression and staring zombie-like at ceilings in institutions, Jerry Finley was displaying symptoms of normality. Still, it presented a terrible dilemma.

Sex among the mentally ill is a taboo subject. The public, not unexpectedly, wants nothing to do with it. The medical profession likes to pretend it doesn't exist, hoping if will go away. To some extent it does. Many of the heavy tranquilizing drugs given to the mentally ill play strange tricks on the hormonal system. At worst, they make men impotent. Women grow fat and sprout mustaches.

In mental institutions, patients aren't supposed to have sex lives, although often they do - behind the shrubs on the grounds. "Bush Therapy" it is called, while the staff look the other way. That is, until a woman becomes pregnant. Family planning is not on the agenda at most mental hospitals.

In the case of Jerry Finley, something had to be done. The staff at the center was very worried. He needed a girl friend, they decided, if he wasn't to be arrested as a public nuisance and returned to the hospital. But how, and where? And what if Jerry did have a girl frient - would his libido sustain the challenge in the face of the drugs he had been taking? Just when they were discussing the possibility of finding a compassionate street lady and taking her fee from petty cash, Jerry met Ellen at a clinic where they both were waiting for refills of medication.

"I think you look nice," Jerry told the plump, middle-aged woman in the ill-fitting cotton dress. Like him, she had been in an out of mental institutions all her life.

"You are pretty. Will you have sex with me?" he said.

Unlike the women Jerry propositioned on the street, Ellen did not turn away in disgust and fear to seek the nearest policeman. "Crazy talk," after all, is the lingua franca in the world she inhabits. Instead, she paused, staring at this thin, middle-aged man who was nervously awaiting her reply.

"I'll think about it," she said. "I'm not sure now. I will have to get to know you better."

The following week Jerry invited Ellen to a party at the center. He wore newly purchased, second-hand blue jeans, rolled up trendy-style over his sneakers, and displayed the beginnings of a beard.

"I'm waiting to see how it turns out," Ellen said when asked if she liked the stubble on Jerry's chin.

They held hands like the teenagers they had never been and danced practically every number.

Alas, the romance was short lived, only about three weeks in all. Suddenly Ellen stopped coming to the center. No one understood why.

"She doesn't love me anymore, I suppose," muttered Jerry, turning away when people asked where she was.

Whether Ellen ever got to know Jerry well enough also remains a mystery. There were, after all, few places they could have gone to be alone. Ellen still lived in an institution, and Jerry shared a room in a community housing unit with two other mental patients.

Still, Jerry no longer frightens women on the street, though occasionally he gets fresh with female staff at the center. For a while he stopped washing, returning to incoherent mumblings about being "a no good good-for-nothing."

But recently, he's become more philosophical. "Women," he tells everyone who cares to listen, "are trouble. I don't want to get married. I'm not ready yet."