<a href="/keyword/mood-disorders/" >mood disorders</a> Part II ONSET, COURSE, PREVALENCE, GENDER DIFFERENCES: MAJOR DEPRESSIVE DISORDER * Onset: - onset may be at any age - average onset: mid to late 20's - trend: earlier and earlier * Course: - with each episode, more episodes likely - after 3 episodes, life-long MDD likely Lifetime Prevalence: - 10-15% Gender differences: - 2:1 ratio (female: male) * * DYSTHYMIC DISORDER * Onset: - usually childhood or teens - onset is slow * Course: - chronic by definition (at least 2 years of duration) - may develop into unipolar MDD Lifetime Prevalence: - 6% of population will develop dysthymia in their lifetime Gender differences: - 5:2 (female: male) * * BIPOLAR I DISORDER * Onset: average 18; 50% started by adolescence trend: earlier and earlier rarely starts after age 40 more acute onset than MDD - Precursor symptoms: labile affect, ADHD-like presentation (temper tantrums, hyperactive, impulsive); anger and violence; high sensitivity; quick to cry, sensitive to criticism and rejection; easily overwhelmed, easily over-stimulated); poor sleep pattern, violent nightmares * Course: - worse with childhood onset risk of deterioration without treatment pattern may change throughout life chronic disorder, but manageable with medication * * Lifetime Prevalence: - about 1.5% Gender differences: - 1:1 (female: male) - males have more manic, females have more depressive episodes BIPOLAR II DISORDER * * * * Onset: - average of 22 Course: - may develop into bipolar I disorder Lifetime Prevalence: - about 1-2% Gender differences: - 3:2 (female: male) - males have more hypomanic, females more depressive episodes CYCLOTHYMIC DISORDER * Onset: - teenage years - onset tends to be slow * * * Course: - 50% later meet criteria for bipolar I or bipolar II disorder Lifetime Prevalence: - about 1-2% Gender differences: - 3:2 (female: male) GENETICS OF <a href="/keyword/mood-disorders/" >mood disorders</a> * * No single gene is responsible for any of the <a href="/keyword/mood-disorders/" >mood disorders</a> <a href="/keyword/mood-disorders/" >mood disorders</a> are polygenic disorders Twin studies: * * * If one identical twin has major depressive disorder (MDD) - there is a 46% chance the other identical twin also has MDD If one fraternal twin has major depressive disorder (MDD) - there is a 20% chance that the other fraternal twin also has MDD If one identical twin has bipolar I disorder: - there is a 40% chance that the other identical twin also is bipolar - there is an 80% chance that the other identical twin is bipolar OR has MDD <a href="/keyword/mood-disorders/" >mood disorders</a> AND CREATIVITY * * * * * <a href="/keyword/mood-disorders/" >mood disorders</a> , (especially bipolar disorder) are over-represented among creative individuals such as poets, writers, and painters About 20% of famous poets found to be bipolar, vs. only about 1% in the general population Many of them committed suicide (e.g., Virginia Woolf, Sylvia Plath) High productivity and creativity especially in hypomanic state Exuberance, new associations, depth of feelings