Rob Reiner's Son Nick Diagnosed With Schizophrenia Before Allegedly Killing His Parents, New Medication Caused 'Alarming' Behavior

Rob and Michele Reiner's troubled son Nick was diagnosed with schizophrenia before he allegedly murdered both of his parents on Sunday, December 14.

According to a new report, the medication the 32-year-old was recently prescribed caused "alarming" behavior and made him become "erratic and dangerous."

Nick had previously entered a treatment facility, and about "three to four weeks" before the tragedy, doctors changed his medication — however, his behavior worsened. Medical professionals were trying to adjust the levels but hadn't found a solution, with an insider claiming Nick's drug abuse made things more stressful.

"Nick was out of his head," one source said of the situation.

Though Nick had a good relationship with his parents despite his years of substance abuse, things appeared to have changed within the past few weeks.

So much so, one insider claimed that the Princess Bride director admitted he was "petrified" of Nick the night before the murder.

An anonymous source claimed that at Conan O'Brien's star-studded Christmas party on December 13, Rob told people, "I can’t believe I’m going to say this, but I’m afraid of my son. I think my own son can hurt me."

As OK! reported, it's believed that Nick slit his parents' throat inside their Brentwood, Calif., home and ran off to a Santa Monica hotel. When a massage therapist couldn't get into the home on the afternoon of December 14, she called their daughter, Romy, 28, who discovered her father's dead body, which was already in rigor mortis.

Despite previous reports, Romy never told the cops they should consider her brother a suspect.

Nick was apprehended and arrested around five hours later.

Nick was charged with two counts of first-degree murder, and because he allegedly used a knife in the brutal slayings, he could face the death penalty or life in prison without parole if convicted.

Romy and her other brother, Jake, 34, put out a statement on Wednesday, December 17, asking for privacy as they mourn the unimaginable loss.

"Words cannot even begin to describe the unimaginable pain we are experiencing every moment of the day. The horrific and devastating loss of our parents, Rob and Michele Reiner, is something that no one should ever experience," they shared. "They weren’t just our parents; they were our best friends."

"We are grateful for the outpouring of condolences, kindness, and support we have received not only from family and friends but people from all walks of life," added the siblings, who made no mention of Nick in their message.