What could cause a loss of self worth and social isolation?

The answer is: It may be a sign of depression or an anxiety disorder. Or maybe even a more serious psychological condition. You or the person suffering from these sx should see a counselor to determine what is the exact condition or what are the possible conditions. You will then be able to get help. Counseling of various types and medication if needed.

Self Worth: Being hurt by others that matter to you, early hurts that have not been resolved that make possibly make you extra sensitive to others opinions. Isolation leaves to your own negative thoughts which can make your mood lower even more, this is a time you need to push yourself what is needed not what you feel like doing. Consult a clinical psychologist who can help you regain your esteem. Best.