Pain often hides behind behavioral changes. A cat that stops jumping onto the counter might not just be "getting old"; it may be suffering from osteoarthritis.
Noise phobias (fireworks, thunder) are a major focus of veterinary behavioral health, often treated with short-term anxiolytics. The Role of the Veterinary Behaviorist
Similar to human OCD, animals can develop repetitive behaviors like tail-chasing or flank-sucking. These often require a mix of environmental changes and medication.