With 10 kids in the family, four of them teen-agers, Jimmy's father had read all the pamphlets on drug use. He had even given talks on drugs to groups of parents. He knew the signs.

When Jimmy was about 16, his father noticed that Jimmy semmed incoherent much of the time. His blue eyes, so like his father's, looked as though you could see right through them, his father recalled. He would just break off in the middle of a sentence. He seemed incapable of remembering anything.

One day, Jimmy's father went to the boy's room and "sniffed around."

There, tucked inside a stereo speaker were a dozen neatly rolled marijuana joints. In a hole in the wall, concealed by a picture, lay several small one-ounce bags of phencyclidine, the mind-altering drug known as PCP, called "angel dust" and "killer weed" on the streets. It is a drug that is fast surpassing marijuana in popularity among the nation's youth. It can cause drastic personality changes in the habitual user.

Jimmy's father looks back now on that discovery as "a day of total devastation."

"Here are the things you find that you hope aren't there . . . Here is one of your own who's doing it . . . When you face it, it blows your whole world apart. You ask yourself, "what do I do now? Where do I go from here?"

The things that happened to Jimmy's family over the past four years seem out of context in the familial suburban atmosphere where they were played out. But somehow it all happened to this otherwise close-knit Catholic family from Wheaton as they watched PCP turn the youngest in a row of four boys from a happy-go-lucky affectionate youngster into a liar a thief and a drug dealer - a half-crazed young man capable even of threatening to "slash to pieces" the members of his own family.

It is a story of a father who chaperoned at high school dances, who raised money for the Catholic Church and for his children's school, the recipient of "outstanding parent award," and of a mother who never spent more than 10 days away from her family, who is warm, gentle and active in church affairs.

It all seemed to fail Jimmy. He saw himself as an outsider, the black sheep of the family who needed to prove that he was special.

Blessed with good looks and charm, Jimmy, at 19, has been jailed, stabbed, nearly beaten to death, and at one point, banished from his own home.

After four years of daily PCP use, two mental hospitals and numerous psychiatrists, Jimmy says he is now ready to pick up the pieces of his life and start afrresh.

"I'm tired . . . I'm tired, man. I got . . . I mean . . . I just got so much to look forward to in life." he says in a slurred, slow-paced speech - a legacy of his years of PCP use. It seems that something is going to explode inside him everything he starts to speak.

Whether Jimmy will make it still a question mark for his parents. But the lingering question that gnaws at them constantly, they say, is "how did this happen to us?"

I was always a curious kid," Jimmy says as he begins to relate his story outside the family's Montgomery County home. There are bicycles in the driveway, a basketball hoop on the garage, swings in the backyards. A flag is displayed for Flag Day.

When Jimmy was 11, and a student in elementary school, he picked up an older brother's baseball glove. Stashed inside was a small plastic bag full of pot.

"I didn't know what it was, so I took it to school. This one kid, he knew what it was so we smoked it. I choked, I coughed, like I got sick, I couldn't stand it."

But just as he'd grow accustomed in the sixth grade to smoking cigarettes, by eighth grade, Jimmy and his friends were smoking pot before and after school and during recess. Whenever the teachers would let them outside for gym, they'd sneak off to a wooded area near the school and smoke pot.

Jimmy liked the sort of familial bond his pot-smoking created between him and his friends. It set them apart from the other kids at school. Most important to Jimmy was the way it made him feel superior to his older brothers.

"I have a lot of brothers . . . They always told me to get lost, you know. 'Get lost, you're nothing but trouble.' That's what they'd say. They put me down, man. They put me down really bad."

He constantly got in trouble in those days, Jimmy's mother recalls. The first time Jimmy was caught shoplifting - six Bic pens from a Montgomery Ward store - she remembers how upset she became.

"I was shocked to think he would do something like that . . . That was breaking the law and breaking God's commandment."

Jimmy's mother says she used to break down and cry whenever a policeman would come to the door with Jimmy because he was found drunk or involved in something like shooting slingshots at cars. She soon learned - through habit - to take these things in stride.

In the ninth grade, Jimmy went to a school where his brothers were known as athletes and serious students and parents were involved in several activities. Jimmy took an after-school job mowing the lawn for two men who rented a house near his home.

One day he say the men mixing an odd-smelling liquid substance in a container in the kitchen. The two men caught Jimmy looking and threatened him if he reported what he saw to the police. In return for keeping silent, he got to take his first couple of "hits" of PCP.

For the next two years, during the 10th and 11th grade, Jimmy says he smoked an ounce of PCP a day.Most PCP users smoke the drug, as Jimmy did, sprinkled on parsley or basil leaves. Because it looks like marijuana and is smoked, many youths, who don't know of PCP's added potency and who would otherwise stay away from harder drugs, are tempted to try it, drug officials say.

"I just kept getting high, getting more burnt out, more burnt out. Kept going down, down," Jimmy says.

At home his presence was like a time bomb ticking away for every member of the family. Things began disappearing around the house, "little things like this ring," Jimmy's father says, fingering the silver pinkie ring he wears," which I'd find later in Jimmy's room."

Jimmy began stealing money from his parents and birthday money from his brothers and sisters. Once he stole a large sum of money his father had raised for his high school and his father then had to replace the money.

Things also appeared mysteriously. Stereos, stereo equipment, cassettes, eight track tapes, car radios.

Jimmy broke into a neighbor's house and stole a stereo only to return it the next day. Soon he was being blamed for whatever went wrong in the neighborhood. One neighbor, whom Jimmy's family had been friendly with for almost 20 years, sarcastically told Jimmy's mother one day that the neighbors were thinking of taking up a collection to send Jimmy away.

Soon Jimmy learned that PCP wasn't only a good way of getting high. It also meant money. Lots of it. Once he got his hands on just an ounce of PCP, he could make a $200 profit on a $150 purchase. Soon he was making $3,000 to $6,000 a week.

He began buying leather jackets, $300 suits.

The PCP was apparently easy enough to find. 'All you had to do," Jimmy says, is "walk down the street . . . or go to a party and say, 'Hey, man, where can I get some KW?Where can I get some Green?"

At home, it was a nightmare, Jimmy's parents recall, as their son seemed less and less in touch with reality.

"One night Jimmy came home flying high on something. And he spent the whole night in my arms, crying like a baby, and you know that he's over six foot. I thought to myself, this has got to be it, he can't get much lower than this. I thought now he'll wise up.

"The next morning when he got up from bed, he didn't remember a thing about what had happened," recalled Jimmy's father, a burly soft-spoken man who worked himself up from construction equipment operator to a field supervisor.

It was about that time that he found the drugs in Jimmy's room. "We knew something had to be done, but what? Who do you go to? The police? . . . I tried to talk to Jimmy. I told him "Look, you only have two more years of (high) school. We'll do the best we can for you, but you've got to help yourself.

"(He'd say) Why are you always lecturing me, Dad."

Jimmy's mother had little more success with her son than her husband.

"There was this one time when I was really afraid he'd do something to the little kids. I was sitting at the table, helping one of the little kids with homework and Jimmy leaned in over the doorway next to the kitchen. He had this strange expression on his fact. He said. 'You know, I could just kill you all.'

"I know now this was his way of crying out for help."

Although there were no overt attempts at suicide, Jimmy seemed to be on an extended dare with deaths. He swallowed quaaludes with beer. He drank fifths of vodka in a singe evening.But most of all, he found himself in the midst of fights, usually with drug thefts.

After one of these fights, for which he was hospitalized, Jimmy's parents asked that he be examined for drug use. The hospital found that he was a heavy user of PCP.

"We had to do something," Jimmy's father said. So they enrolled him in a drug day care program based at Montgomery General Hospital. The family began receiving counseling at Bethesda Community Psychiatric Clinic. Jimmy went to his therapy sessions only a few times, then withdrew. His parents meanwhile continued with the counseling.

To this day, Jimmy's parents disagree over the benefits of counseling. "They'd ask us a lot of questions, but if you ask them what can be done, they don't give any answers," Jimmy's father said.

"They asked me, what kind of pregnancy did you have? When did Jimmy first talk, when was his first smile. I guess some mothers write these things down. But I didn't," Jimmy's mother said.

So she began keeping notes on Jimmy's teen-age behavior in a black-covered record book. Now, however, the entries were not about first smiles or first words. They said things like "Using pot heavily . . . weekly (counseling) sessions not enough . . . Jimmy is stabbed in the back."

As the family's attention centered more and more on Jimmy, jealousy grew among the other members of the family.

"We were spending all this money on Jimmy . . . At one point we had used up all the family's savings. We had to say to the older boys, you can't have this or that right now because we just don't have the money. It was hard for them to understand," Jimmy's mother said.

She and her husband became more suspicious of their other children - and the kids noticed it. "They say to us we weren't being fair to them, and we weren't," Jimmy's mother said.

Jimmy's father began scouting around for a mental hospital to place the boy in. He found that most were far more expensive than he could afford. Then he learned that the juvenile court will help pay for the rehabilitative care of youths who are deemed beyond parental control.

So one day in July, 1975, Jimmy's parents told the juvenile court they could no longer control their son.

"It was just terrible. It was admitting that you are a failure as a parent," Jimmy's mother said of the court appearance.

But through the court, Jimmy was able to enter a hospital but seemed to make little progress.

After he came home, Jimmy soon slipped back into his old life style. He was dealing drugs regularly, and then, in a fight with a man who claimed Jimmy had stolen PCP from him, Jimmy was stabbed in the back on the lawn of a Silver Spring apartment building. The knife had ripped into one of his lungs, causing it to collapse.

When Jimmy was released from the hospital, he was 18 years old and his father asked him to move out of the house.

"It had just gotten too much for my husband. He had just been hurt too much," Jimmy's mother said.

Jimmy subsequently spent a month on the West Coast with relatives. When he returned, he told his parents he had changed.

"I just looked at myself in the mirror. I thought, hey man, this isn't me. I looked like a ghost, a skeleton . . . I just had to get it together."

Now Jimmy has a steady job and his own place to live. He talks about trying to get into TV commercials like a girl he knows who's been in Coca Cola ads. He thinks he'd like to write about his experiences, so he might prevent other kids from using PCP. He would call the book "The KW Connection," he says, because those are the initials of Killer Weed, and of the Kensington-Wheaton area where he grew up.

His relationships with his family seem to be improving. One morning last month, he hailed his father in the street to give him a Fathers Day present.

"My father, you know, like, he smiled at me."