A new study has unveiled some negative aspects of anxiety. The study suggests that when people are anxious, smells they once found neutral or pleasant become distasteful.

Scientists used powerful new brain imaging technologies to understand the pros and cons of anxiety. The study revealed how anxiety or stress can rewire the brain, linking centers of emotion and olfactory processing, to make typically benign smells malodorous.

Researchers led by Wen Li, a professor of psychology at the University of Wisconsin-Madison Waisman Center, said that the brains of human subjects experience anxiety induced by disturbing pictures and text of things like car crashes and war transform neutral odours to distasteful ones, fuelling a feedback loop that could heighten distress and lead to clinical issues like anxiety and depression.

The study serves crucial for mankind as it may help scientists understand the dynamic nature of smell perception and the biology of anxiety as the brain rewires itself under stressful circumstances and reinforces negative sensations and feelings.

“After anxiety induction, neutral smells become clearly negative. People experiencing an increase in anxiety show a decrease in the perceived pleasantness of odours. It becomes more negative as anxiety increases,” Li said.

The scientists used Functional MRI to understand the effects of anxiety during the study. Functional MRI is a technology that enables clinicians and researchers to observe the working brain in action. In the course of the experiment, researchers observed that two distinct and typically independent circuits of the brain – one dedicated to olfactory processing, the other to emotion – become intimately intertwined under conditions of anxiety.

The study was published in the Journal of Neuroscience.