Fear of bright daylight could trigger panic attacks, said a study.
There have been several hints in earlier research as well that photophobia is associated with panic disorder.
"For example, in some people, fluorescent light can induce panic attacks. It had also been noted that people with panic disorder often protect themselves from light by wearing sunglasses," said lead researcher Giulia Campinoti from the University of Siena, Italy.
To understand it further, researchers compared 24 patients with panic disorder against 33 healthy people.
Using a standard Photosensitivity Assessment Questionnaire, they found that healthy controls showed a slight tendency to be photophilic - to be attracted to bright light.
In contrast, the patients with panic disorder showed medium to high levels of aversion to bright light.
"We believe that photophobia is one of the elements, which may increase the risk of people suffering from panic attacks," Campinoti added.
We do not yet know exactly what the relationship might be but there is probably some underlying biochemical basis, he said.
The findings were shared at the 27th ECNP Congress in Berlin, Europe's largest meeting on applied neuroscience.
