The real reasons Shemar Moore, Mandy Patinkin, Paget Brewster, and more quit Criminal Minds

Shemar is a fan favorite and was on the series for 11 seasons before calling it quits and spontaneously appearing as a guest star later on.

The star portrayed Derek Morgan for over a decade, however, he was ready to challenge himself in new ways acting-wise.

He revealed to TV Guide: "I've treated my acting career like school. The Young and the Restless: eight years. [That was] high school. Criminal Minds: college. Now I'm ready for grad school, a Ph.D., whatever you want to call it. I'm just ready to grow." 

He continued: "I just want to leap. And I don't know where I'm going to land, but I believe that I'm going to land. ... I'm not leaving to go be a big star. I'm not leaving to go make a bunch of money. ... I'm leaving because I just creatively want to be fueled and [am] excited to try new things and see what else I'm capable of."

Besides wanting a fresh start with new characters, Shemar also wanted to focus more on his personal life and self-development. 

He added: "I wanted to see what the next chapter of my acting career is and also have a little balance so I could pursue other avenues of my life. I want to get married, I want to have kids, I want to travel." 

Mandy played the character of FBI Special Agent Jason Gideon, however, he left during season three despite his growing popularity due to the show.

He left the series to protect his mental health, revealing to New York Magazine: "The biggest public mistake I ever made was that I chose to do Criminal Minds in the first place."

Mandy admitted: "I thought it was something very different. I never thought they were going to kill and rape all these women every night, every day, week after week, year after year. It was very destructive to my soul and my personality. After that, I didn't think I would get to work in television again."

Lola Glaudini portrayed FBI BAU Special Agent Elle Greenaway during the series.

She left the show after the second season because after someone shot her character during a violent scene, she began to suffer from PTSD, according to multiple reports.

On top of that, she also preferred living closer to family and friends on the East Coast.

Paget Brewster portrayed the character of Emily Prentiss and she replaced Lola's character Elle.

During the fifth season, she left the show and candidly explained why on X, previously known as Twitter.

She revealed: "'Creative Reasons' has been an Executive [expletive] excuse for decades. It is financial. AJ is a dreamboat. And yes, I am hurt too."

Paget made a comeback in season seven and then she officially returned in season 12 and became the team leader on the show.

Thomas played the character of FBI Special Agent Aaron "Hotch" Hotchner, and he had a different reason for leaving the show.

In 2016, Thomas had an on-set physical altercation with Virgil Williams, who was a writer and producer on the series, due to a disagreement over the plot. 

In 2010, Thomas was required to undergo anger management training due to an incident with an assistant director.

After the second aggression, he was initially suspended for two episodes, however, his past history led to him being ultimately fired from the series.