The trial of a Duxbury woman charged with murdering her three young children begins on Monday at Plymouth Superior Court and is expected to draw intense local and national attention.

Lindsay Clancy’s defense team isn’t expected to dispute that she committed these crimes. Instead, the trial is likely to center around the mental health treatment Clancy was receiving at the time for postpartum depression.

Clancy’s attorney, Kevin Reddington, has said Clancy was in a state of psychosis after being prescribed more than a dozen different medications that were supposed to improve her mental state. He plans to seek what is known as the insanity defense, arguing Clancy should not be held criminally responsible for her actions on the January evening in 2023 that she strangled her children, 5-year-old Cora, 3-year-old Dawson and 8-month-old Callan, at the family’s home.

Legal experts said it may be difficult for a jury to embrace this strategy. Several attorneys with experience in criminal defense said jurors are often reluctant to accept an insanity defense — especially in the case of a horrific crime involving young children.

“It’s a hard pill to swallow that the defense is gonna get up there and say, ‘Lindsay Clancy did everything that she’s accused of, find her not guilty,’ ” said Ryan Sullivan, a defense attorney who is not part of this trial.

After the killings, authorities said Clancy tried to kill herself by slitting her wrists and throat, and jumping from a second story window. She was left paralyzed from the waist down and is being held at Tewksbury Hospital, a state facility for those with mental and physical illnesses.

Even if the insanity defense is successful, Clancy would not be released from custody. She would remain in a state facility and undergo periodic reviews to determine whether she could return to live in the community.

Kevin Reddington, defense attorney for Lindsay Clancy, addresses Plymouth District Court during Clancy’s arraignment in February 2023. (David L. Ryan/The Boston Globe via Getty Images file)

The trial, which is expected to last about a month, has a witness list of nearly 200 people. They include Clancy’s husband, Patrick, as well as medical professionals, state and local police, and fire officials who responded to the crime.

The first step will be jury selection. It could take several days to seat 18 jurors, including six alternates. Legal experts say the makeup of the jury could play a key role in the trial’s outcome.

“It is going to be really hard to find fair jurors that are open to the idea of a mental health defense, but not predisposed toward it,” said Sullivan, the defense attorney who is not involved in this case. “It’s a razor-thin line.”

In pre-trial hearings, Plymouth Superior Court Judge William Sullivan ruled that prosecutors will be allowed to play a recording of the 911 call Patrick Clancy made when he returned home from getting takeout and found his wife on the ground outside the house. He then discovered his three children in the basement while on the phone.

But the judge also ruled that the defense cannot call other women who have experienced postpartum depression and postpartum psychosis as witnesses. Prosecutors argued that testimony could lengthen the trial.

Many women said they hope the trial will help educate people about how common it is for new mothers to struggle with their mental health. Amy Colozzo, board co-chair of the Massachusetts chapter of Postpartum Support International, said about one in five moms will experience a perinatal mental health disorder. The group describes perinatal mood disorders as “the most common complication of childbirth.” Colozzo said many people are reluctant to get treatment or admit they’re not having a rosy motherhood experience.

She is hopeful that this case will help educate people about how common perinatal mental health problems are.

“What we hope is that people understand the symptoms, know who they can talk to and get connected with treatment,” Colozzo said.

Perinatal mental health treatment is individualized, said Dr. Uruj Kamal Haider, medical director of the Massachusetts Child Psychiatry Access Project for Moms. She advises patients to strongly advocate for effective treatment and make sure they’re getting enough time with their providers, especially their psychiatrists.

Haider said patients, families and doctors should all be aware of the subtle warning signs indicating that postpartum mental health issues could escalate.

“Postpartum psychosis, perinatal psychosis — it’s a spectrum,” Haider said. “There does not have to be full blown auditory or visual hallucinations for a mom to be psychotic. The mom may just present as paranoid or confused or just very irritable and that can escalate very quickly especially with intense sleep deprivation.”

In addition to the criminal case, Clancy and her husband each have filed separate civil lawsuits against her healthcare providers.

Patrick Clancy’s lawsuit alleges that providers failed to properly monitor his wife’s prescription medications including Zoloft, Prozac, Klonopin, Seroquel and Ambien, among others. The lawsuit claims she was often overwhelmed and anxious, and had extended her maternity leave from her job as a labor and delivery nurse at Massachusetts General Hospital. His complaint outlines a timeline of her mental healthcare, saying his wife sought additional help and went to both outpatient and inpatient psychiatric care. It also alleges that she only had brief appointments with a psychiatrist, and that medical professionals did not take action when he reported that his wife was having panic attacks and thoughts of suicide.

“If Defendants had not acted negligently, and rather had provided adequate care, it is more likely than not that Patrick and Lindsay’s children would still be alive today,” his attorney argued in the complaint.

A police cruiser sits in the driveway at 47 Summer Street, the home of Lindsay Clancy in Duxbury, Massachusetts. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)

Whatever the outcome of the criminal trial, several medical professionals said it will be significant in drawing attention to postpartum mental healthcare. Dr. Michelle DiBlasi, a psychiatrist at Tufts Medical Center, said about 80% of women experience a mild version of postpartum depression — what she describes as “postpartum blues.”

“We do know there is a significant amount of women who are experiencing psychiatric symptoms that maybe they’ve never experienced before — feeling down, crying more, feeling more anxious,” DiBlasi said. “That’s why it’s really important to highlight for people that this is a common occurrence.”

She said treatment typically consists of antidepressants — though they don’t work for everyone. A patient may have to try out different medications to find something that works, DiBlasi said, and it can take about six weeks to determine whether a medication is effective.

While DiBlasi said more research could lead to better treatments for postpartum depression, there are new medications showing promise. Zuranolone, the first — and so far the only — FDA-approved medication for postpartum depression was cleared in August 2023, just seven months after the Clancy children were killed.

Resources: You can reach the National Suicide Prevention Lifeline at 988 and the Samaritans Statewide Hotline (call or text) at 1-877-870-HOPE (4673). Call2Talk can be accessed by calling Massachusetts 211 or 508-532-2255 (or text c2t to 741741).

The National Maternal Mental Health Hotline cal be reached at 1-833-TLC-MAMA.