Last week, a Massachusetts judge declared a mistrial in the case of Lindsay Clancy who has admitted to strangling her three children to death in 2023. Three jurors interviewed by NBC10 Boston said there was one juror who held out on acquitting Clancy. According to one juror, the holdout admitted that he had reasonable doubt but said, “I’m still not going to say that she’s not guilty by reason of insanity.” The defence argued that Clancy suffered from postpartum psychosis and that she didn’t receive appropriate medical care. As David Rossman, criminal law expert and emeritus professor at Boston University wrote in an email to PBS, “The jury in a case like this really acts as a proxy for the moral sense of the community.” 

What is postpartum psychosis?

Postpartum psychosis is a condition that impacts a person’s sense of reality after childbirth. It can cause delusions, hallucinations, and paranoia among other issues. In some cases, postpartum psychosis is diagnosed as schizophrenia, a chronic mental health disorder that can also cause people to lose touch with reality. Women’s health specialists have been pushing for postpartum psychosis to be added to the Diagnostic and Statistical Manual of Mental Disorders. But the evidentiary threshold for inclusion in the DSM is hard to overcome. Only one new diagnosis has been added since 2013, and the stakes are high – postpartum psychosis can occur in women who have no history of mental illness and can lead to suicide or infanticide.  

Understanding the evidentiary threshold a diagnosis must meet for inclusion in the DSM

Generally speaking, a diagnosis must pass through four categories of evaluation before being included in the DSM: diagnostic validity, diagnostic reliability, clinical utility and harm reduction, and public review. Diagnostic validity measures whether the diagnosis is measuring something distinct. Diagnostic reliability checks whether multiple clinicians come to the same diagnosis using the proposed criteria. Clinical utility and harm reduction ensures the diagnosis has a practical, clinical application and is not just academic. This also ensures that normal human behaviour won’t be prematurely medicalized or pathologized and that people won’t be over-prescribed. Finally, public reviews put the proposed diagnosis under rigorous scrutiny from the psychiatry community. 

What is preventing postpartum psychosis from being entered into the DSM

One of the main reasons that postpartum psychosis hasn’t been entered into the DSM is that it’s considered a manifestation of bipolar disorder. At the moment, it’s recorded in the DSM as peripartum onset that’s attached to either a mood disorder or a psychotic disorder. Psychiatric nosology focuses on classification based on core symptoms rather than triggers or specific time windows of experience. Nosology is the branch of medical sciences that deals with classifying and grouping diseases. There’s also trouble getting consensus within the psychiatric community on whether there are distinct cognitive or diagnostic features. They find that there’s overlap with mania or certain affective states. 

What impact will postpartum psychosis’ inclusion in the DSM have on society?

If postpartum psychosis is already recognized as a manifestation of bipolar or mood disorders, what difference would it make to give it its own specific diagnosis in the DSM? According to advocates, DSM recognition of postpartum psychosis would lead to more training for doctors, more funding for research, and more judges taking it seriously as a mitigating factor in criminal cases. According to Dr. Veerle Bergink, director of Mount Sinai’s Women’s Mental Health Center, “This is the strongest phenotype in psychiatry, with such a clear onset, such a clear trigger, such a clear biology there.” A phenotype is the observable set of behaviour or characteristics that arise from how a person’s genes interact with their environment.

How have courts dealt with postpartum psychosis cases in the past

Postpartum psychosis, while dangerous, is considered relatively rare. So how have courts dealt with people who’ve used postpartum psychosis as an explanation for criminal actions? In the U.S., individuals have to meet their state’s definition of criminal insanity. It’s not enough to simply be diagnosed with a mental illness. Some definitions of criminal insanity require the defence to prove that the accused was not in a state to recognize that something was wrong or to understand what they were doing. In some cases, the defence has to prove that even though the defendant knew what they were doing was wrong, they couldn’t resist the impulse.