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.
Paranoia occurs in many mental disorders, but is most often present in psychotic disorders. Paranoia can become delusions, when irrational thoughts and beliefs become so fixed that nothing (including contrary evidence) can convince a person that what they think or feel is not true.