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.
If excessive worrying and high anxiety go untreated, they can lead to depression and even suicidal thoughts. Although these effects are a response to stress, stress is simply the trigger. Whether or not you become ill depends on how you handle stress.