Carina is 50 years old,and her moods are rather unpredictable.Some days she is excited and happy,other days she is sad and withdrawn.Her symptoms seem fairly mild,but she has had mood swings of this type since she was in her early 20s.Which disorder is most consistent with Carina's symptoms

A)  dysthymic disorder 
B)  cyclothymic disorder 
C)  dissociative identity disorder 
D)  undifferentiated schizophrenia

Carina's symptoms are most consistent with cyclothymic disorder, which is characterized by mild mood swings that cycle between periods of depression and hypomania (mild mania). These symptoms have persisted over a long period of time, which also supports a diagnosis of cyclothymic disorder. Dysthymic disorder involves persistent feelings of sadness, but not necessarily mood swings; dissociative identity disorder involves distinct and separate identities or personalities, which is not mentioned as a symptom for Carina; undifferentiated schizophrenia involves more severe symptoms such as delusions and hallucinations.