Lindsay Clancy, a Massachusetts labor-and-delivery nurse, admitted to strangling her three young children in January 2023. Her defense argued she was in the grip of postpartum psychosis and wasn't criminally responsible. But the clinicians who saw her in the weeks before the killings weren't treating her for psychosis. They were treating her for suicidality and other postpartum psychiatric symptoms.

Prosecutors argued she knew what she was doing and had planned it. After five weeks of testimony, more than 80 witnesses, and seven days of deliberation, the jury couldn't agree. A mistrial was declared September 4. Prosecutors have not yet said whether they'll retry the case.

It's easy to see why this case has captured so much attention. The legal question alone is complicated, but the case leaves clinicians with harder questions to sit with: “Would I recognize postpartum psychosis if it showed up in my practice? Would I have caught it?” Probably not every time, if we’re honest. 

Postpartum psychosis is rare—roughly 1–2 cases per 1,000 births—but it's a psychiatric emergency. It can include delusions and hallucinations, but also mania, severe depression, confusion, insomnia, agitation, and rapidly shifting symptoms.

We tend to imagine psychosis as obvious: a patient who is hallucinating, paranoid, or disorganized. But postpartum psychosis isn't necessarily that tidy, and the Clancy case shows how murky the picture can be before psychosis is obvious, if it emerges at all.

 In the weeks before the killings, Clancy made two trips to the ER, called suicide hotlines twice, and voluntarily admitted herself to a psychiatric hospital for five days. Her documented treatment focused largely on suicidality, intrusive thoughts, depression, anxiety, and insomnia rather than psychosis. Intrusive thoughts of harming a baby can occur in postpartum OCD and, when ego-dystonic, are very different from psychotic beliefs or commands. For example, a mother with postpartum OCD might have the thought, “What if I smother my baby?” and be horrified by it, recognize it as irrational, and take steps to make sure she never acts on it. A mother with psychosis, by contrast, might believe that her baby is possessed and that killing the baby is necessary to save the baby's soul. The challenge is figuring out when a disturbing thought is an obsession, and when it reflects a loss of reality testing.

Even the expert witnesses disagreed in hindsight. The prosecution's mental health experts testified Clancy was not psychotic at the time of the killings; the defense's forensic psychiatrist, Phillip Resnick, MD, testified that she was. If experts examining the same history after the fact can't agree, it's not surprising that clinicians seeing her in real time struggled to determine what was happening.

 Some warning signs deserve particular attention, even when psychosis itself isn't yet obvious:

• Severe or rapidly worsening insomnia, especially a decreased need for sleep
• Abrupt mood elevation, irritability, agitation, or mixed/manic symptoms
• Confusion, disorganization, or markedly unusual behavior
• New paranoia, unusual beliefs, hallucinations, or impaired reality testing
• Suicidality or rapidly escalating psychiatric symptoms
• Thoughts about the baby that are no longer clearly experienced as unwanted or irrational

None of this tells us whether Clancy was psychotic when she killed her children, and it’s not up to us to decide. But we can take away important lessons from it for our clinical practice: A reassuring mental status exam is a snapshot only; there’s no guarantee what tomorrow will look like, especially in a postpartum patient whose symptoms are still evolving.

When a postpartum patient is deteriorating, pay attention, particularly with severe insomnia, suicidality, unusual thinking, or emerging manic symptoms. Ask yourself, "Is she psychotic right now?" but also, "Could postpartum psychosis be emerging?" If the answer is plausibly yes, our threshold for urgent reassessment, collateral information, and, when safety is uncertain, hospitalization should be low. 

Postpartum psychosis is uncommon but missing it can be catastrophic. And while the Clancy case remains unresolved, its clinical warning is clear. For a deeper dive into postpartum psychosis, see "Postpartum Psychosis: A Primer" in CHPR, Oct/Nov/Dec 2023. For a more comprehensive review, we suggest our course, Mood Disorders in Pregnancy, Postpartum, and Breastfeeding: A Carlat Review Course. And for more on the forensic side of cases like this one, don't miss our interview with Jacqueline Landess, MD, JD, DFAPA, "Competency to Stand Trial: A Primer for Psychiatrists."

Sources: NPR, CNN, and Boston Globe trial coverage, August–September 2026.