Arlin Cuncic looks at the connection:
People procrastinate for many reasons, but the immediate goal is to bring a temporary sense of relief. The problem with procrastination is just that; the relief is temporary, and it is eventually replaced with anxiety about being behind in what you need to get done.
If you suffer with social anxiety disorder (SAD), you probably procrastinate out of fear of disapproval or failure. Perhaps you put off making phone calls, delay discussing difficult issues at work, or get behind scheduling health appointments, haircuts, or any other task that involves interacting with people.