A forensic psychologist took the stand Monday in the murder trial of Lindsay Clancy, testifying that the Massachusetts mother has been diagnosed with bipolar disorder. The testimony is central to Clancy's defense, which argues she was suffering from severe postpartum mental illness at the time she killed her three young children in January 2023.

The judge presiding over the trial denied a defense motion for mistrial after a witness made an unsolicited reference to religion during testimony. The judge ruled the comment did not rise to the level of prejudice warranting a new trial, and proceedings continued.

Clancy, a labor and delivery nurse, allegedly strangled her children — ages five years, three years, and eight months — at the family's Duxbury, Massachusetts home before jumping from a window. She survived with serious injuries. Her defense team has argued that a cascade of prescribed psychiatric medications contributed to a mental breakdown, while prosecutors contend she acted with intent and must be held accountable.

The forensic psychologist's testimony detailed Clancy's psychiatric history and argued her mental state at the time of the killings was severely compromised. Prosecutors are expected to challenge that assessment with their own expert witnesses. The case has drawn national attention and prompted broader public debate about postpartum psychiatric conditions and criminal responsibility.