An<unk>  (or<unk>  is one type of emotional and behavioral disorder, along with externalizing disorders, and low incidence disorders. People who have an<unk>  will keep their problems to themselves, or internalize the problems.
Internalizing disorder
Externalizing disorder
Mixed anxiety–depressive disorder
Psychopathy
Personality disorder
Identity disorder
Dissociative identity disorder
Body dysmorphic disorder