Dissociative Disorders

Dissociation is a common defense/reaction to stressful or traumatic situations. Severe isolated traumas or repeated traumas may result in a person developing a dissociative disorder. A dissociative disorder impairs the normal state of awareness and limits or alters one’s sense of identity, memory or consciousness. Once considered rare, recent research indicates that dissociative symptoms are as common as anxiety and depression, and that individuals with dissociative disorders (particularly Dissociative Identity Disorder and Depersonalization Disorder) are frequently misdiagnosed for many years, delaying effective treatment.

An example of this is Bipolar disorder.

https://www.nami.org/Learn-More/Mental-Health-Conditions/Dissociative-Disorders