The New York City Police Department's use of the stop-and-frisk tactic has so badly damaged some communities' trust in police, according to a new study, that many young people won't report violent crimes.

The Vera Institute of Justice conducted a survey of 500 men and women in five "highly patrolled" New York City neighborhoods-- Jamaica in Queens, East Harlem, Bedford-Stuyvesant and East New York in Brooklyn, and the South Bronx--who were between the ages of 18 and 25, and who had been stopped by police at least once.

Forty-five percent of those surveyed, according to the report, encountered "an officer who threatened them, and 46 percent said they had experienced physical force at the hands of an officer." Twenty-five percent said they'd been involved in a stop in which a cop has drawn a weapon.

An alarming 44 percent said they'd been stopped repeatedly by police officers--at least nine times. Some even reported being stopped more than 20 times. (Here's The New York Times video profile of a young Brooklyn man stopped over 60 times.)

Only 29 percent of respondents said they'd been informed of the reason for being stopped.

Eighty-five percent said "illegal items such as weapons, drugs, or open containers of alcohol were never discovered during a stop they had been involved in"-- which matches up with the NYPD's own statistics. Eighty-nine percent of those stopped last year weren't arrested or issued a summons.

All of these factors, the study finds, contribute to a lack of young people's trust in New York's finest. “Our main finding is pretty plain and simple: Stop-and-frisk is compromising the trust needed for public safety,” Jennifer Fratello, lead researcher for the study, told The New York Daily News.

Eighty-eight percent of those surveyed said they believed their community did not trust the police. Only 40 percent said they'd be comfortable asking the police for help if they were in trouble.

Sixty percent said they would not talk to police even when they were the victim of violence.

The majority of those surveyed were black or Latino. In 2012, the NYPD stopped 533,042 people, 87 percent of whom were either black or Latino.

A federal judge ruled last month that the NYPD's use of stop and frisk was unconstitutional and amounted to widespread racial profiling. She appointed a federal monitor to oversee the department. Mayor Michael Bloomberg, who says stop and frisk keeps guns off the street and saves lives, appealed the ruling.

The New York City Council also passed two bills last month to rein in the NYPD's use of stop and frisk. One bill sets up the office of the inspector general, which will act as a watchdog over the department. The other bill makes it easier for New Yorkers to sue if they've been profiled based on their race, religion, or sexual orientation.

Related on HuffPost:

Loading Slideshow...
  • When we asked Caleb, 15, of Fort Greene, if he'd ever been stopped and frisked, he responded, "Nah, but most of my friends have. Only a matter of time, I guess."

  • Three weeks into a year's vow of silence, Matthew Swaye wrote on a piece of paper that he'd been arrested five times protesting stop-and-frisk since Oct. 21. Asked why he'd taken his vow, he wrote, "Men talking too much. :)"

  • New York City Council Member Daniel Dromm's district has the third-highest rate of stop-and-frisks in the city. People in his district had been stopped by police 18,000 times in 2011, he said. "It's outrageous and has a chilling effect," he said. Along Roosevelt Avenue, he added, cops targeted LGBT residents, disproportionately accusing them of prostitution. Dromm was joined at the protest Sunday by members of The Campaign To Stop False Arrests.

  • Ernest Johnston, of Harlem, said four years ago, a cop mistook him for somebody else and pulled a gun. The case of mistaken identity was cleared up, but it rattled him. Johnston is now an activist concerned with the stretch of Lexington Avenue between 110th and 125th Streets, which he says has the highest concentration of former prisoners re-entering society, often with criminal records that prevent them from getting jobs and housing.

  • George Mack, of South Jamaica, said Mayor Bloomberg, Police Commissioner Ray Kelly and City Council Speaker Christine Quinn are "trying to criminalize my children."

  • Richard said he was beat up by cops in 1996 and then charged with assaulting a police officer. His case went to trial and he was acquitted of the assault charge. <strong>Correction: A previous version of this article incorrectly stated that the assault charges were dismissed.</strong>

  • Carol Porteous said she's scared that her 15-year-old son will be harassed.

  • Reverend Michael Ellick of Judson Memorial Church is one of the founders of <a href="" target="_hplink">Occupy Faith</a>, an offshoot of the Occupy Wall Street movement. He said that ever since 9/11, "security" in New York has trumped everything else.

  • All this woman holding a Trayvon Martin sign would say is, "No justice, no peace."

  • Marty Brod, a New York native and World War II veteran, said Bloomberg's NYPD was creating a "police state." Stop-and-frisk, he said, is "demeaning" and doesn't reduce crime.

  • Kevin (right) said he'd been arrested twice in one week on charges that were later dismissed.