The Lindsay Clancy murder trial is nearing its conclusion — and the battle over her state of mind has never been more intense.

On today’s Hot Mics with Billy Bush, Billy breaks down the explosive cross-examination of prosecution forensic psychiatrist Dr. Avram Mack by Lindsay’s defense attorney, Kevin Reddington.

Reddington challenges Mack over his experience treating women with postpartum mental illness, his evaluation of Lindsay years after the deaths of her children, and his conclusion that Lindsay suffered from major depressive disorder — not psychosis — and understood that what she was doing was wrong.

Billy plays the highlights from an increasingly contentious confrontation between Reddington and Mack and explains why he believes the testimony may have done more damage than good to the Commonwealth’s case.

But the larger question goes far beyond one expert witness:

What happens when a mother repeatedly asks for help — and the mental-health system fails to recognize what is happening to her?

Before the deaths of her three children, Lindsay experienced debilitating insomnia and intrusive thoughts. She visited emergency rooms, attended a day program, called a suicide hotline, entered a residential treatment program and repeatedly sought psychiatric help. Over the course of her treatment, she received numerous prescriptions involving 13 different medications.

Yet no one diagnosed her with postpartum psychosis.

As closing arguments approach, Billy examines the difficult question at the center of the trial: Should Lindsay Clancy be treated as an ordinary murderer, or was she suffering from a catastrophic mental illness that left her incapable of criminal responsibility?

Billy also revisits his memorable 2005 interview with Tom Cruise over psychiatry and psychotropic medication, including Cruise’s controversial criticism of Brooke Shields after she publicly discussed using Paxil to treat postpartum depression.

Finally, Billy delivers his own closing argument in the Lindsay Clancy case — and explains why he believes this tragedy represents not only the deaths of three children, but a profound failure of America’s mental-health system.