Beliefs are certainty of reality that we accept as true. What they give us is the basic mental scaffolding to understand and meaningfully engage with our world. These beliefs are extremely important to our behavior and identity, but they are not well understood.
Fixed, usually false, but strongly held beliefs not shared widely are called delusions. In prior work, we suggested that studying delusions is informative about cognition itself and how it can go away, as we try to understand unexpected sensory input or social communication considering existing beliefs, memories, and other social information. Then we evaluate our account against how well this explains our experience and how consistent this is with previous beliefs.
It is believed that it passes these criteria. Then it leads us to choose what we focus on and in thinking of other possibilities. Selected informative case studies have contributed to the study of delusions. Unlike large group studies, case studies provide researchers the opportunity to examine more in depth to origins and course of clinical features not accounted for in prevailing theories.
Recently Connors MH et al., published a paper in the international journal Cortex describing a unique case study of a woman who had a brief hospital admission for postpartum psychosis (characterized by hallucinations, delusions, mood swings, and confusion) in which she temporally experienced compelling delusions. Natalie (pseudonym) was otherwise said to have had no prior medical or psychiatric history. After giving birth to her second child, she developed post-partum psychosis in hospital.
Among her delusions, Natalie told of the belief that strangers were her parents-in-law in disguise (the Fregoli delusion). By treatment, Natalie recovered quickly. Interviews and observational data during her delusions and subsequent retrospective accounts provide a unique window into the onset and experience of her delusions. Natalie followed a full recovery and stated that her delusions were strongly held beliefs, she believed in them. They were, she said, like her conviction that her husband was her husband. And contrary to some theories that hold that delusions differ from normal beliefs.
Natalie disagreed and picked out particular features that were connected to her delusions. Natalie would believe strangers were her in-laws if she said they smelled like her in-laws or they held the same mannerisms, behaviors, and speech patterns as she remembers her in-laws. It was based on these cues and other factors that the delusion was thought to have developed by suggesting that inappropriate activation of memory representations of familiar people occurred. Natalie also remembered other beliefs, including that she was dead (known as Cotard’s delusion), which she did not tell doctors when she visited them. ‘It was an idea, because other explanations failed to explain my weird experiences, and I was watching a show on TV,’ she said and added that she had entertained this idea.
Natalie admitted that she eventually fobbed this off as far too implausible while remaining engaged with other delusions. The result implies that the evaluation of belief might depend on the specific delusion, leading to different thresholds for different delusions. And it draws attention to how some delusions are private affairs. Natalie had repeatedly told me that she was actively involved in trying to explain and cope with her experiences throughout all her delusions. She said, she had thought about other explanations and tried them by checking it out further. That implies pretty much the same way we normally form beliefs. ‘Television and movies had shaped Natalie’s ideas,’ she recalled. She also remembered how, when her delusions were established, she elaborated based on things around her.
Reference: Connors MH, Gibbs J, Large MM, Halligan PW. Delusions in postpartum psychosis: implications for cognitive theories. Cortex. 2024;177:194-208. doi:10.1016/j.cortex.2024.04.018
