Psychiatry
Bipolar II Disorder
양극성장애 2형
Recurring hypomania + major depression (no full mania)
- How common
- Lifetime 0.5–1.5%
- Typical age
- Mean onset mid-20s
What is it?
Similar to Bipolar I but milder elevated phase. Mood lability + depressive predominance.
Commonly affected: Amygdala, PFC, striatum
How it develops
- Genetic predispositionShares some loci with BD-I
- Hypomanic onset≥4 days elevated/irritable mood, function preserved
- Depression dominance>50% of lifetime in depressive states
- AD-induced switchSSRI monotherapy may switch to mania
Symptoms
- Major depressionSame as MDD
- Suicide riskHigher attempt rate than BD-I
- Hypomania ≥4dElevated mood, function preserved, no psychosis
- Decreased sleep needDuring hypomania
- Increased creativityOften perceived positively by patient
How it is examined
- DSM-5 BD-II≥1 hypomanic (≥4d) + ≥1 MDE, never manic
- MDQ screeningMood Disorder Questionnaire
- AD response historyPrior switch on SSRIs
Imaging
Similar MRI changes as BD-I.
- Amygdala changes
fMRI: altered emotion regulation circuits.
- Emotion circuit dysregulation
Non-surgical care
- Quetiapine (first-line BD depression)300 mg/day, proven for BD depression
- LamotrigineDepression prevention, minimal cognitive AE
- LithiumRelapse prevention, antisuicidal
- CBT/psychoeducationHypomania recognition, routine management
- Avoid AD monotherapySwitch risk; combine with stabilizer
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Treatment-resistant depression
Procedures that may be discussed
- ECT
- rTMS
- Ketamine (caution in BD)
Outlook
Chronic relapsing. >90% recur. Suicide attempts higher than BD-I.