5.10 Mood Disorders (Depression and Bipolar) Psychiatry Review for the USMLE Step 1 exam Mood disorders are persistent disruptions in emotion, categorized into bipolar disorders and depressive disorders. Bipolar disorders are characterized by manic or hypomanic episodes, while depressive disorders feature periods of depression. Major Depressive Disorder (MDD) is characterized by feelings of sadness, guilt, worthlessness, and anhedonia lasting for at least two weeks. SIG E CAPS is an acronym used to remember the symptoms of depression: Sleep changes, Interest loss, Guilt, Energy loss, Concentration difficulties, Appetite changes, Psychomotor retardation, and Suicidal ideation. In MDD, at least 5 of the SIG E CAPS symptoms must persist for more than 2 weeks. Persistent Depressive Disorder (dysthymia) is a chronic, low-grade form of MDD that lasts for at least two years. Mania is a symptom common to all bipolar disorders, characterized by elevated or irritable mood and increased activity or energy. Mania lasting for at least 1 week is called a manic episode, while hypomania is a less severe form lasting longer than 4 days. The symptoms of mania can be remembered using the mnemonic DIG FAST: Distractibility, Irritable mood/insomnia, Grandiosity, Flight of ideas, Agitation/increased activity, Speedy thoughts/speech, and Thoughtlessness. Bipolar I involves manic episodes, and bipolar II involves hypomanic episodes and major depressive episodes. Bipolar I requires at least one manic episode, while bipolar II requires depressive episodes. Mood stabilizers such as lithium, valproate, carbamazepine, and lamotrigine are used to treat bipolar disorders. Litium is the best (notable exeptions however). Antidepressants are contraindicated for bipolar patients due to the risk of flipping into mania. The risk of suicide is high in bipolar patients, with 25-50% attempting suicide and 10-15% dying by suicide. Cyclothymia is a less common form of bipolar disorder characterized by cycling between hypomania and mild depression over many years.