Sometimes people pretend that they have either a mental or physical illness when they don't have either. This is usually done for attention, or to enable them to get out of doing something. While it may not be malicious in intent, it is a form of manipulating and lying and it can really hurt other people who go out of their way to take care of this person, or it can stifle the development or opportunities for the person faking it. Whatever the case, being able to spot the pretense can provide a good opener for helping this person to find more constructive ways to deal with the underlying issues.