Mood disorders

The following types of disorders are classified under mood disorders:

Major depressive disorder or MDD

Major depressive disorder is characterized by depressed mood or anhedonia (lack of pleasure) plus at least 5 out of 9 of the following symptoms (SIGECAPS):

• S. sleep disturbances. These include early morning awakenings and repeated nighttime awakenings. EEG shows decreased slow-wave sleep, decreased REM latency, and increased total REM sleep.

• I. loss of interest

• G. guilty feelings of worthlessness

• E. loss of energy

• C. loss of concentration

• A. changes in appetite or weight

• P. psychomotor agitation or retardation

• S. suicidal ideation

Symptoms should last at least 2 weeks.

Atypical depression: This is the most common subtype. It’s characterized by hypersomnia, overeating, mood reactivity (highs and lows), and leaden paralysis (legs and arms feel heavy).

Dysthymic or persistent depressive disorder: This involves symptoms of depression that last for > 2 years. It’s often milder, and >2 symptoms in SIGECAPS is needed for diagnosis.

Seasonal affective disorder or MDD with seasonal pattern: This is characterized by seasonal, recurrent depressive features (more commonly atypical depression features). Symptoms occur during fall and winter, or rarely in summer months, for at least 2 years. It’s more common in younger females who live in colder climates with less sun exposure. Patients with seasonal affective disorder have more serotonin transporter protein, less serotonin and Vit D, and higher melatonin in winter.

Bipolar disorder types I and II: This is characterized by periods of extremely “up,” elated, irritable, or energized behavior (known as manic episodes) alternating with very “down,” sad, indifferent, or hopeless periods (known as depressive episodes). Less severe manic periods are known as hypomanic episodes. Some patients may have mixed episodes.

Bipolar I Disorder: This is defined by manic episodes that last at least 7 days, or by manic symptoms that are so severe that the person needs immediate hospital care. Depressive episodes usually occur as well, typically lasting at least 2 weeks.

Bipolar II Disorder: This is defined by a pattern of depressive episodes and hypomanic episodes, but not the full-blown manic episodes that are typical of Bipolar I Disorder.

Cyclothymic Disorder: This is defined by periods of hypomanic symptoms as well as periods of mild depressive symptoms lasting for at least 2 years (1 year in children and adolescents). Symptoms are milder.

Role of lithium in bipolar disorder

• First line therapy for bipolar disorder. It helps treat acute manic episodes and depressive episodes, reduces recurrence of symptoms, and decreases the risk of suicide.

• Lithium inhibits glycogen synthase kinase 3, leading to decreased neuronal apoptosis and cell death and an increase in gray matter in the anterior cingulate gyrus, amygdala, and hippocampus, which are involved in emotional processing and cognitive control.

• It also blocks inositol monophosphatase, decreasing the levels of myoinositol, IP3, and DAG in the brain.

• Adverse effects of lithium include nausea, diarrhea, dry mouth, polyuria (treat with amiloride or thiazides), tremors, weight gain, amnesia, cognitive effects, sexual dysfunction, acne, psoriasis, nephrogenic diabetes insipidus, hypothyroidism, hypercalcemia, hyperparathyroidism.

• Lithium is teratogenic, causing Ebstein anomaly in the fetus.

• Worsening tremors, slurred speech, ataxia, and cognitive defects are signs of lithium toxicity.

• ACEIs and NSAIDS decrease lithium excretion and increase the risk of toxicity.

• Hemodialysis is needed to treat severe lithium toxicity.

Table showing the types of postpartum depression

Premenstrual dysphoric disorder (severe PMS or late luteal dysphoric disorder): This is characterized by mood changes such as irritability, lethargy, difficulty concentrating, depressed mood, anxiety, anger, and decreased interest. It can also include sleep disturbances and weight changes, breast tenderness, and joint and muscle aches. These symptoms cause significant impairment in functioning and are associated with the menstrual cycle (typically up to a week before menses).