Bright sunlight, or fear of bright sunlight, is associated with panic attacks, according to new research.

Past studies have shown that seasons do affect panic disorder, but a new study has looked specifically at how light could trigger a panic attack, according to PsyPost.org.

Researchers from the University of Siena in Italy compared 24 panic disorder patients with 33 control patients who did not have a mental illness diagnosis. The healthy group was attracted to bright light, while the group with panic disorder demonstrated an aversion to bright light.

A Photosensitivity Assessment Questionnaire was used and asked patients to rate statements like "My ideal house has large windows," or "Sunlight is so annoying to me, that I have to wear sunglasses when I go out," PsyPost.org reported.

"There have been several hints 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, for example by wearing sunglasses," said lead researcher Giulia Campinoti.

"We believe that photophobia is one of the elements which may increase the risk of people suffering from panic attacks, but this is a small study, so it needs to be confirmed by a longer-term follow-up trial," Campinoti continued. "For example, we need to understand if the photosensitivity and panic attacks continue to be related over time.  If we can confirm this, then we may be able to take steps to avoid some of the triggers to panic attacks. It is important to note that our work shows an association, not necessarily a cause and effect. We don't yet know exactly what the relationship might be, but there is probably some underlying biochemical basis".

These findings confirm that depression, combined with anxiety, cannot be treated with light therapy.