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.
Stress has physical causes (I'm cold, I'm tired) and psychological causes (I'm confused, I'm worried) that can feed one another and grow to anxiety and then panic if not controlled. Many dive emergencies, like avalanches, start with a minor problem--a leaky mask, say, or a sticky power inflator.