A new study from researchers at the University of Nottingham in England has uncovered a surprising connection between sleep quality and susceptibility to conspiracy theories. 

The findings, published in the Journal of Health Psychology, suggest that individuals with poor sleep habits, including those with clinical insomnia, are more likely to believe in conspiracy theories, particularly after being exposed to conspiratorial content.

“We know a lot about the cognitive biases, social influences, and personal traits that explain why people believe in conspiracy theories. However, previous research has typically overlooked how sleep, especially poor-quality sleep, may impact conspiracy beliefs,” the study’s lead author, Daniel Jolley, who holds a PhD in social psychology, tells Study Finds.

The research involved more than 1,100 participants across two studies. The first study examined how participants’ sleep quality influenced their belief in a conspiracy theory related to the 2019 Notre Dame cathedral fire. Those with poor sleep were markedly more likely to believe in conspiratorial theories about the origins of the fire—including unfounded rumors that it was a deliberate attack, perhaps by Islamic extremists—compared to their well-rested counterparts. 

The second study sought to understand the psychological mechanisms behind this connection, exploring factors like anger, paranoia, depression, and anxiety. The researchers discovered that depression played a particularly significant role in linking poor sleep to increased belief in conspiracy theories. 

“We also know from previous research that sleep deprivation can directly increase anxiety, anger, and feelings of depression, which are predictors of conspiracy beliefs. We argue that by prioritizing good sleep, individuals can improve both their mental and physical health, which will likely strengthen their ability to think critically and resist misinformation in an increasingly complex world,” Dr. Jolley said.

The team found that poor-quality sleep clouds judgment, leading to irritability and mental fog. This state of “fuzzy thinking” makes people more susceptible to the allure of conspiracy theories, the study found. These narratives, which often frame major events as secret plots carried out by powerful groups, might feel more coherent or emotionally validating to someone experiencing negative emotions.

In addition, the study highlighted what researchers call a “sleep cycle of conspiracy beliefs.” Poor sleep worsens mental health, leading to greater vulnerability to conspiratorial thinking. This, in turn, can further degrade sleep quality, perpetuating a harmful feedback loop.

One particularly concerning statistic from the study noted that 74 percent of people have reported worse sleep quality recently. This widespread sleep deprivation, coupled with societal stressors, could be quietly fueling the spread of conspiracy theories on a massive scale.

While the study firmly establishes a link between poor sleep and conspiracy beliefs, it stops short of proving causation. Dr. Jolley suggests further research is needed, including controlled experiments on sleep deprivation, to solidify the understanding of how sleep affects conspiracy thinking.