PSY 301 1st Edition Lecture 23Outline of Last Lecture I. GenesII. Dopamine HypothesisIII. Multiple NeurotransmittersIV. Prenatal InfluencesV. Physiological Reactions to StressVI. Mood DisordersVII. Clinical DepressionOutline of Current Lecture I. Bipolar DisorderII. ManiaIII. HypomaniaIV. Genetics and Mood DisordersV. Neurotransmitters and Mood DisordersVI. Brain Dysfunctions and Mood DisordersVII. Environmental Factors and Mood DisordersCurrent LectureBipolar DisorderLifetime prevalence rate 4%1. no gender difference2. all cultural and ethnic group3. all ages, less common in kids4. more in higher SESa. probably a matter of diagnosisBipolar I: alternation of depression and mania or hypomaniamania: 1. elevated, expansive mood2. grandiose to delusions of grandeur3. little sleep4. racing thought5. very talkative6. risk taking7. 15-20% develop psychotic delusions or hallucinationshypomania: shorter and less severePatterns of episodes vary:1. can be as short as a few hours or as long as a few months2. some alternate and some don’t3. some patients have many manic episodes and some have very few4. some patients have mania and depression together (mixed states: a combination of symptoms of both simultaneously)There is usually no external trigger1. sometimes there are early warning indicators2. stressful life experiences often precede episodes60% of people with bipolar disorder are alcohol or drug abusersHigh risk of suicide 1. greater risk even than for depression2. roughly 20% of bipolar patients commit suicideGenetics & Mood Disorders High heritability 1. Concordance rates are higher for identical than for fraternal twinsa. depression: identical 50% fraternal 20%b. bipolar disorder: identical 60%fraternal 12%2. Bipolar involves complex inheritance, not a single gene. 3. seem to be separate inheritance pathways for depression and bipolara. people with one of these disorders tend to have relative with that disorder, but not with the other mood disorder4. Kids adopted away from depressed or bipolar parents at higher riska. greater effect for bipolarNeurotransmitters & Mood Disorders3 critical neurotransmitters: 1. norepinephrine2. dopamine3. serotonin Mechanism is unclear but involves more than just too little or too much of the neurotransmitters1. in depression, antidepressant drugs immediately increase the available NTs but clinical effects don’t appear for several weeks 2. in bipolar the question pattern of cycling seems unconnected to neurotransmitter levels People are more vulnerable to mood disorders if they have the variant of the short allelefor the serotonin transporter geneBrain Dysfunctions & Mood DisordersDepression1. associated with heightened activity in the subgenual cingulate cortex (part of the limbic system) 2. low levels of brain activity in the left prefrontal cortex3. enter REM sleep more quickly and spend more time thereBipolar Disorder: 1. greater amygdala volumes 2. greater brain activity in subcortical emotion- generative brain regions such as the amygdalaEnvironmental Factors and Mood DisordersEnvironmental factors in depression:1. families with high levels of expressed negative emotionsa. predicts onset and relapse rates2. more negative life events as kids3. severe stressors in the 6-9 months prior to depressiona. one-third of these reflect genetic tendencies to high risk behavior4. lack of intimate relationships, especially for womenEnvironmental factors in bipolar disorders:1. high life stress predicts higher relapse rates and longer recovery
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