13 of 14

Self-doubt

Persistent self-doubt and second-guessing is a common feature of anxiety disorders, including generalized anxiety disorder and OCD. In some cases, the doubt may revolve around a question that's central to a person's identity, like "What if I'm gay?" or "Do I love my husband as much as he loves me?"

In OCD, Winston says, these "doubt attacks" are especially common when a question is unanswerable. People with OCD "think, 'If only I would know 100% for sure whether I was gay or straight, either one would be fine,' but they have this intolerance for uncertainty that turns the question into an obsession," she says.