A 26-year-old woman presents to the emergency department with her boyfriend because she has not been sleeping well for the past 2 weeks. The patient reports sleeping about 2 hours per night, but she feels like she has plenty of energy. Her boyfriend reports that the patient is not at her baseline and has been exhibiting “unusual behaviors” that are causing him concern. Of note she has made over 500 posts to her Instagram page in the last 5 days. The patient reports that she did not want to come to the emergency department but that she came to appease her boyfriend. During the interview, the patient’s speech is rapid and uninterruptable but fluent. The patient’s affect is expansive, and she gets up several times to pace the room during the interview. She reports that she has begun a new business venture allowing her to quit her previous marketing job. Her boyfriend confirms that she has founded a new business, but he has always known her to love her marketing job. When asked about her past psychiatric history she reports a history of a major depressive episode during college which resulted in her failing a semester. She currently denies suicidal and homicidal ideations. Physical examination is unremarkable. Complete metabolic panel and urine toxicology screen are unremarkable.
Which of the following is the most likely diagnosis?
- A) Bipolar 1 disorder
- B) Bipolar 2 disorder
- C) Borderline personality disorder
- D) Disinhibited social engagement disorder
- E) Insomnia disorder
B) Bipolar 2 disorder
Bipolar 2 disorder is a mood disorder that consists of at least 1 major depressive episode and one hypomanic episode. A hypomanic episode is a deviation from normal mood with increased energy/activity that consists of an elevated or expansive mood lasting at least 4 consecutive days. The change in mood must be noticeable by others and must cause impairment in functioning but is not severe enough to warrant psychiatric hospitalization. Three of the following must be present in addition to the mood disturbance: grandiosity, decreased need for sleep, increased speech, racing thoughts, distractibility, increased goal directed activities or physical movements, and increased involvement in activities that are risky.
In this clinical vignette, the patient meets the criteria for bipolar 2 disorder. She has a previous major depressive episode and is currently hypomanic. A hallmark of bipolar 2 is poor insight. She has an expansive mood with psychomotor agitation and is so distracted during the interview that she gets up from the exam table. She has a decreased need for sleep, pressured speech, and increased goal-directed behaviors. Her increased goal-directed behaviors consist of her increased posting to social media and have led to her risky decision to leave her job suddenly for a new business opportunity. The patient is not a harm to herself or to another person, and she is not psychotic, so she does not warrant an inpatient psychiatric hospitalization.
Answer choice A: Bipolar 1 disorder, is incorrect. Bipolar 1 disorder presents similarly to Bipolar 2 disorder, however the distinction in this vignette is that the patient does not meet criteria for a manic episode. To meet criteria for a manic episode the patient would have more severe symptoms necessitating psychiatric hospitalization.
Answer choice C: Borderline personality disorder, is incorrect. While there is not enough information in the vignette to rule out borderline personality disorder, it is not the primary presenting problem.
Answer choice D: Disinhibited social engagement disorder, is incorrect. Disinhibited social engagement disorder is exclusively a pediatric diagnosis.
Answer choice E: Insomnia disorder, is incorrect. In this case the insomnia present in the vignette is better explained by another mental disorder.
Key Learning Point
Bipolar 2 disorder is a mood disorder that consists of at least one major depressive episode and at least one episode of hypomania.