A 33-year-old woman is brought to the physician by her husband because of persistent sadness for the past 2 months. During this period, she also has had difficulty sleeping and an increased appetite. She had similar episodes that occurred 2 years ago and 9 months ago that each lasted for 4 months. Between these episodes, she reported feeling very energetic and rested after 3 hours of sleep. She often went for long periods of time without eating. She works as a stock market trader and received a promotion 5 months ago. She regularly attends yoga classes on the weekends with her friends. On mental status examination, she has a blunted affect. She denies suicidal thoughts and illicit drug use. Which of the following is the most likely diagnosis?

Major depressive disorder with seasonal pattern

Major depressive disorder with atypical features

A 29-year-old man comes to the physician with his wife because she has noticed a change in his behavior over the past 2 weeks. His wife reports that he is very distracted and irritable. His colleagues have voiced concerns that he has not been turning up for work regularly and behaves erratically when he does. Previously, her husband had been a reliable and reasonable person. The patient says that he feels “fantastic”; he only needs 4 hours of sleep each night and wakes up cheerful and full of energy each morning. He thinks that his wife is overreacting. The patient has been healthy except for a major depressive episode 5 years ago that was treated with paroxetine. He currently takes no medications. His pulse is 98/min, respirations are 12/min, and blood pressure is 128/62 mm Hg. Mental status examination shows frenzied speech and a flight of ideas. Which of the following is the strongest predisposing factor for this patient's condition?

Maternal obstetric complications

A 19-year-old woman presents to an outpatient psychiatrist after 2 weeks of feeling “miserable.” She has been keeping to herself during this time with no desire to socialize with her friends or unable to enjoy her usual hobbies. She also endorses low energy, difficulty concentrating and falling asleep, and decreased appetite. You diagnose a major depressive episode but want to screen for bipolar disorder before starting her on an anti-depressant. Which of the following cluster of symptoms, if previously experienced by this patient, would be most consistent with bipolar I disorder?

Impulsivity, insomnia, increased energy, irritability, and auditory hallucinations for 2 weeks

Insomnia, anxiety, nightmares, and flashbacks for 6 months

Elevated mood, insomnia, distractibility, and flight of ideas for 5 days

Impulsivity, rapid mood swings, intense anger, self-harming behavior, and splitting for 10 years

Auditory hallucinations, paranoia, and disorganized speech for 2 weeks

A 23-year-old woman is brought to the emergency department by her boyfriend 10 minutes after ingesting at least 15 acetaminophen tablets. She has been admitted to the hospital several times in the past few months after attempted self-harm. She claims that her boyfriend is “extremely selfish” and “does not care for her.” She says she feels lonely and wants her boyfriend to pay attention to her. Her boyfriend says that they have broken up 10 times in the past year because she is prone to outbursts of physical aggression as well as mood swings. He says that these mood swings last a few hours and can vary from states of “exuberance and affection” to states of “depression.” On examination, the patient appears well-dressed and calm. She has normal speech, thought processes, and thought content. Which of the following is the most likely diagnosis?

Borderline personality disorder

Narcissistic personality disorder

A 23-year-old woman is brought to the physician by her father because of irritability, mood swings, and difficulty sleeping over the past 10 days. A few days ago, she quit her job and spent all of her savings on supplies for a “genius business plan.” She has been energetic despite sleeping only 1–2 hours each night. She was diagnosed with major depressive disorder 2 years ago. Mental status examination shows pressured speech, a labile affect, and flight of ideas. Throughout the examination, she repeatedly states “I feel great, I don't need to be here.” Urine toxicology screening is negative. Which of the following is the most likely diagnosis?

Attention-deficit hyperactivity disorder

A 24-year-old woman presents to her primary care physician for a wellness exam. She currently has no acute concerns but has been feeling hopeless, has a poor appetite, difficulty with concentration, and trouble with sleep. She says that she has poor self-esteem and that her symptoms have been occurring for the past 3 years. She has had moments where she felt better, but it lasted a few weeks out of the year. She currently lives alone and does not pursue romantic relationships because she feels she is not attractive. She has a past medical history of asthma. Her mother is alive and healthy. Her father committed suicide and suffered from major depressive disorder. On physical exam, the patient has a gloomy demeanor and appears restless and anxious. Which of the following is the most likely diagnosis?

Disruptive mood dysregulation disorder

A 19-year-old female college student is brought into the emergency department by her boyfriend. The boyfriend reports that the patient got caught stealing from the company she works for and subsequently got fired. The boyfriend received a text that evening saying “I’ll miss you.” When he arrived at her dorm room, the patient was slumped in the shower covered in blood. The patient agreed to be driven to the emergency room. When asked about what happened, the patient replies “I just want out of this life.” The patient has bipolar disorder, and takes lithium as prescribed. She has a psychiatrist she sees every week, which the boyfriend confirms. She has never had a prior suicide attempt nor has she ever been hospitalized for a psychiatric disorder. The patient’s vitals are stable. Upon physical examination, a 4 centimeter vertical incision is noted on the patient’s left forearm. During the patient’s laceration repair, she asks if she will be admitted. She states, “these ups and downs are common for me, but I feel better now.” She verbalizes that she understands that she overreacted. She asks to go home, and her boyfriend insists that he will stay with her. They both confirm that neither of them have guns or know any peers with access to guns. Which of the following is the most appropriate management for the patient?

Involuntarily admit the patient

Have the patient sign a suicide contract before discharge

Set up a next-day appointment with the patient’s psychiatrist

Discontinue lithium and start valproate

A 38-year-old woman comes to the physician for a follow-up visit. She has a 2-year history of depressed mood and fatigue accompanied by early morning awakening. One week ago, she started feeling a decrease in her need for sleep and now feels rested after about 5 hours of sleep per night. She had two similar episodes that occurred 6 months ago and a year ago, respectively. She reports increased energy and libido. She has a 4-kg (8.8-lb) weight loss over the past month. She does not feel the need to eat and says she derives her energy ""from the universe"". She enjoys her work as a librarian. She started taking fluoxetine 3 months ago. On mental exam, she is alert and oriented to time and place; she is irritable. She does not have auditory or visual hallucinations. Physical examination shows no abnormalities. Which of the following is the most likely diagnosis?

Medication-induced bipolar disorder

Bipolar II disorder diagnostic criteria for USMLE Step 2 CK: High-Yield Psychiatry Lessons

Diagnostic Criteria - The Bipolar II Blueprint

Core Requirement: At least 1 hypomanic episode AND at least 1 major depressive episode.
Absolute Exclusion: There has NEVER been a full manic episode.
Hypomanic Episode Defined:
- Lasts ≥4 consecutive days.
- ≥3 symptoms from DIGFAST (4 if mood is only irritable).
- Unequivocal change in functioning, observable by others.
- NOT severe enough to cause marked impairment, hospitalization, or psychosis.
Major Depressive Episode Defined:
- Lasts ≥2 weeks with ≥5 symptoms of depression.

⭐ Bipolar II is frequently misdiagnosed as recurrent major depressive disorder. Always screen for a history of hypomania in patients presenting with depression.

📌 DIGFAST Mnemonic:

Distractibility
Indiscretion/Impulsivity
Grandiosity
Flight of ideas
Activity ↑
Sleep ↓
Talkativeness ↑

Bipolar I, Bipolar II, and Cyclothymia mood states

Hypomania vs. Mania - The Defining Difference

Core Feature: Both involve a distinct period of abnormally elevated, expansive, or irritable mood and increased energy, plus ≥3 other symptoms.
Mnemonic (Symptoms): 📌 DIGFAST
- Distractibility
- Indiscretion/Impulsivity
- Grandiosity
- Flight of ideas
- Activity (goal-directed) ↑
- Sleep need ↓
- Talkativeness (pressured speech)

⭐ A patient presenting with major depression who experiences a manic or hypomanic episode after starting an SSRI should be evaluated for an underlying bipolar disorder. Antidepressant monotherapy can induce mania.

Differential Diagnosis - The Mood Disorder Lineup

Major Depressive Disorder (MDD): Key distinction is the absence of any lifetime hypomanic or manic episodes.
Cyclothymic Disorder: Chronic (≥ 2 years) fluctuating mood with numerous hypomanic and depressive periods that do not meet full criteria for an episode.
Borderline Personality Disorder (BPD): Mood lability is moment-to-moment and reactive to interpersonal stressors, unlike the sustained days-to-weeks episodes in Bipolar II.
Substance/Medication-Induced: Symptoms are physiologically linked to intoxication or withdrawal.

⭐ The most common misdiagnosis for a patient with Bipolar II disorder is recurrent Major Depressive Disorder, as hypomanic episodes are often underreported or missed.

High‑Yield Points - ⚡ Biggest Takeaways

Diagnosis requires at least one hypomanic episode and at least one major depressive episode.

Crucially, there has never been a manic episode; this distinguishes it from Bipolar I.

Hypomania lasts for at least 4 consecutive days but doesn't cause marked functional impairment.

Hypomanic episodes are not severe enough to require hospitalization and lack psychotic features.

The major depressive episodes are often the reason for seeking treatment.

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