Thyroid disease in cats is linked to heart disease and a fast heartbeat in conjunction with any other symptoms of thyroid problems is cause for a trip to the vet. Once the hyperthyroidism is treated, your cat's heart rate should return to normal.
Stress reaction â some studies have found that paranoia is more common in people who have experienced severe and ongoing stress â for example, prisoners of war. How stress can trigger paranoia is unclear.
Feelings of paranoia can be observed with many psychological disorders, including schizophrenia, as well as with a number of medical diseases, ranging from Alzheimer's disease to multiple sclerosis, that can affect brain function. Medically Reviewed by a Doctor on 6/25/2014.