We caught up with the writer Monday on "TMZ Live," where he reflected on his connection with the Bad Boy Records founder, and how he believes drugs changed Diddy's mindset over the years.

As Touré put it ... Diddy was a different person decades ago, describing the rapper as "extremely sharp, motivational, [and] very strategic" in the early days of his career. While Touré didn't get into specifics, he did say he thought Diddy's mind had been "clouded" for the last 15 years.

He added, "He's not in his right self ... It's been a haze of drug abuse and that's why he's making these horrendous decisions."

Touré made it clear he wasn't trying to excuse Diddy's behavior ... rather, he was trying highlight how Diddy ended up in this position.

TMZ broke the story ... Diddy was arrested last Monday at the Park Hyatt in Midtown Manhattan, 6 months after his Los Angeles and Miami homes were raided in connection with a federal criminal investigation.

The rapper was indicted the next day in an NYC courtroom, where he was charged with sex trafficking, racketeering conspiracy, and transportation to engage in prostitution. Prosecutors say Diddy's "Freak Offs" are central to their case ... claiming the rap mogul "used violence and intimidation" to ensure participation in the X-rated activities.

Following Diddy's arrest, his attorney, Marc Agnifilo, said his client was "not a perfect person," confirming his client had been wrapped up in "drug use" and "toxic relationships" ... but assured the media that Diddy was an "innocent man with nothing to hide."

Diddy has pled not guilty to all the charges in the federal indictment.