When former Boston Celtic (2000-2001) Chris Herren was in college, he had to listen to a former NFL player talk about his struggles with substance abuse.

Though Herren did not want to attend the assembly because he thought it did not pertain to him, his coach said it was mandatory for all athletes or he would be suspended for a game. Reluctantly, Herren went, sitting in the top left corner of the bleachers.

“I sat there and said, ‘I will never ever turn out to be him,'" Herren said. "And that’s the moment I remember the most. Because I would give anything to get back to the seat that you’re sitting in today and pay attention and change the way I was living.”

Herren never thought he would be the man with the microphone almost 20 years later.

At 18-years-old, not long after that assembly, Chris Herren tried cocaine for the first time. He vowed he would do it once, and never again. But since that day for the next 14 years, he struggled with drug abuse and ended his professional basketball career early. More importantly, he was not there for his wife and children.

While playing for the Denver Nuggets (1999-2000), Herren became addicted to OxyContin. He tried cleaning up in 2000, breaking out in cold sweats and vomitting. Then his phone rang, with Rick Pitino on the other line, welcoming him to the Boston Celtics.

"And what was probably supposed to be the best day of my life, why I practiced in gyms across Massachusetts, that moment was one of the worst days of my life, because I knew I was going right back to these oxys," Herren said.

After a long journey and almost killing himself by overdosing on several occasions, Herren finally got the help he needed and has been drug-free since June 4, 2008 and alcohol-free since Aug. 1, 2008. He now shares his story with students in hopes that they will learn from his mistakes.

Herren recalled one teenage girl from an appearance he made who emailed him, admitting her own drug problems. The next day, Herren returned to the school to speak with the girl. She gave him the drugs she had in her backpack.

“You kids need to know there is no reason to change who you are,” Herren said. “There’s no reason to go out Friday or Saturday night smoking and drinking beer and changing who you are. Because you are perfect just the way you are.”

At the end of the presentation, Norton High School principal Raymond Dewar presented Herren with a purple Lancers basketball jersey.

Norton High students will be reading his memoir, “Basketball Junkie” written with Bill Reynolds for the One School One Book program.

Norton Police Department and its unions paid for half of the presentation, while money was also brought in by the Boosters organization and student activities.