Monroe:
Comorbidity refers to the existence of two disorders or illnesses in a single person, and is very common with certain illnesses (i.e., in my case migraines and bipolar disorder have a strong statistical comorbidity). I've noticed (in therapy, etc.) that most people who suffer from a mental illness actually suffer from two or three different things (my brother has Asberger's syndrome and also has OCD). I know it's not really a direct answer, but it gives you the right term and a little bit of information to continue your searches and questions.
NoesMama