Rob Reiner's Son Nick's Severe Mental Health Disorder Revealed, New Meds Made Him 'Dangerous'

Nick Reiner, son of filmmaker Rob Reiner and Michele Singer Reiner, allegedly killed his parents in their Brentwood home.

Sources have now revealed that a recent medication change for his mental disorder, combined with substance abuse, left him "erratic and dangerous."

Arrested in Downtown LA, Nick Reiner faces two counts of first-degree murder with potential life without parole or the death penalty.

Nick Reiner, Battling Schizophrenia, Became 'Out Of His Head' On New Medication Before Allegedly Killing Parents

Nick Reiner, the middle child of Hollywood director Rob Reiner, had reportedly been struggling with schizophrenia, and sources say a recent change in his medication contributed to increasingly concerning behavior in the weeks leading up to the alleged killings of his parents, Rob and Michele Reiner.

According to TMZ, the 32-year-old's prescription adjustments, intended to stabilize him, instead made him "erratic and dangerous."

Combined with ongoing substance abuse, the changes reportedly further destabilized his mental state. Sources described him as being "out of his head" following the adjustment.

He had been receiving treatment at an exclusive Los Angeles mental health and substance abuse facility that reportedly charges around $70,000 per month.

Nick, who lived in his parents' Brentwood guesthouse, is expected to plead not guilty by reason of insanity. He has a history of violence, substance abuse, and homelessness, and has reportedly sought rehab nearly 20 times.

Nick Reiner Was Arrested And Charged In His Parents' Fatal Stabbing

Following their tragic passing, Rob, 78, and Michele, 70, were discovered by their daughter Romy Reiner stabbed to death in their home, with sources saying their throats had been cut. The LA County Medical Examiner confirmed the deaths resulted from "multiple sharp force injuries" and ruled the deaths a homicide.

Nick was arrested Sunday night near Exposition Park in Downtown Los Angeles after reportedly leaving behind bloody evidence at a Santa Monica hotel. He was initially booked at Parker Center Jail before being transferred to Twin Towers Correctional Facility, where he is being held without bail.

On Tuesday, he was charged with two counts of first-degree murder with a special circumstance of multiple murders, carrying a potential sentence of life without parole or the death penalty.

He made his first court appearance on Wednesday. With disheveled hair, he appeared stoic and somber, wearing an anti-suicide smock and shackled at both hands and feet. He spoke only to confirm to the judge that he wished to waive his right to a fast arraignment, saying, "Yes, your honor."

Nick Reiner's Arraignment Is Set For January 7 As Psychiatric Evaluation Pending

Following the hearing, Nick's attorney announced that his formal arraignment is set for January 7 and urged the public to avoid rushing to judgment, describing the case as "very, very complex and serious."

Seth Zuckerman, a criminal defense lawyer, told the BBC that this delay may be intended to allow for a psychiatric evaluation to determine whether Nick is fit to stand trial.

"The psychiatric evaluation is generally done before arraignment to see if he is even fit to stand trial," Zuckerman said.

LA Police Department Chief Calls The Murder Case 'Heartbreaking'

Prosecutors have stated that no decision has yet been made regarding whether the death penalty will be pursued.

If convicted, Nick faces the maximum penalties of life imprisonment without parole or the death penalty.

"This case is heartbreaking and deeply personal, not only for the Reiner family and their loved ones, but for the entire city," LA Police Department chief Jim McDonnell said.

Rob And Michele Reiner's Children Speak Out, Describe Loss As 'Unimaginable' And Request Privacy

Rob was a celebrated filmmaker whose work spanned multiple genres, directing iconic films such as "This Is Spinal Tap," "Misery," and "A Few Good Men." Michele was an actress, photographer, producer, and founder of Reiner Light, a photography and production company.

For the first time since the tragedy, Rob and Michele's surviving children, Jake and Romy Reiner, issued a public statement. They described their grief as "unimaginable" after the "horrific and devastating loss" of their parents.

They added: "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."

They concluded their statement by  requesting privacy and asking that their parents be remembered for "the incredible lives they lived and the love they gave."