Nightmares could signify the onset of autoimmune illnesses.
An increase in nightmares could be an indicator of autoimmune diseases
A study by the University of Cambridge and King's College London has found an increase in disrupted sleep, nightmares and daytime hallucinations preceded a "flare-up" of the condition lupus.
Three in five of the lupus patients surveyed said that they had experienced disrupted dream sleep several years before other symptoms.
The experts believe that the findings could enable them to recognise lupus flares earlier and allow sufferers to get treatment early.
Dr. Melanie Sloan, lead author of the study from the Department of Public Health and Primary Care at the University of Cambridge, said: "It's important that clinicians talk to their patients about these types of symptoms and spend time writing down each patient's individual progression of symptoms.
"Patients often know which symptoms are a bad sign that their disease is about to flare, but both patients and doctors can be reluctant to discuss mental health and neurological symptoms - particularly if they don't realise that these can be a part of autoimmune diseases."