Transcript Untitled [psychology.okstate.edu]

Mood Disorders: Etiology
Chapter 6
Mood Disorders: Familial and Genetic
Influences
 Family Studies
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Rate of mood disorders is high in relatives of probands
Relatives of bipolar probands are more likely to have
unipolar depression
 Twin Studies
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Concordance rates for mood disorders are high in identical
twins, highest for bipolar disorder
More severe mood disorders have a stronger genetic
contribution (.e.g., bipolar)
Heritability unlikely related to single gene, but interaction
of many genes creates biological vulnerability
Mood Disorders: Neurobiological Influences
 Neurotransmitters
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Mood disorders are commonly related to low levels of
serotonin (5-HT) and norepinephrine (the “catecholamine
hypothesis”)
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Low levels of serotonin metabolites (5-HIAA) in CSF
Effectiveness of antidepressant that act on this system
The “permissive hypothesis” and the regulation of other
neurotransmitter systems
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One function of the serotonin system is to regulate other
neurotransmitter systems within adaptive bounds, including
noradrenergic (norepinephrine) systems
Underactive noradrenergic systems  depression
Overactive noradrenergic systems  mania
Mood Disorders: Neurobiological Influences
 Endocrine system and “stress hypothesis”
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Depression may be linked to excess Cortisol (the “stress
hormone”
Hypothyroidism and Cushing’s Disease
Postpartum Depression
Dexamethasone Suppression Test (DST) – not supported as
specific to depression
Mood Disorders: Psychological Influences
 The Learned Helplessness Theory of Depression
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Related to lack of perceived control over life events
Hopelessness, not just helplessness, may be key to
development of depression
 Learned Helplessness and a Depressive Attributional
Style
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Internal attributions – Negative outcomes are one’s own
fault
Stable attributions – Believing future negative outcomes
will be one’s fault
Global attribution – Believing negative events will disrupt
many life activities
All three domains contribute to a sense of hopelessness
Mood Disorders: Psychological Influence
 Aaron T. Beck’s Cognitive Theory of Depression
 Depression – A tendency to interpret life events less adaptively
 Depressed persons engage in cognitive errors
 Types of Cognitive Errors
 Arbitrary inference – Overemphasize the negative
 Overgeneralization – Generalize negatives to all aspects of a
situation
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Cognitive Errors and the Depressive Cognitive Triad
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Think negatively about oneself (incompetent, unattractive, etc.)
Think negatively about the world (dangerous, cold, etc.)
Think negatively about the future (unchanging, painful, etc.)
 Negative Schema (things are usually my fault)
Mood Disorders: Social and Cultural
Dimensions
 Social Support
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Extent of social support is related to depression
Lack of social support predicts later onset of depression
Interpersonal theory of depression hypothesizes that cause
of depression is strain or loss in interpersonal relationships,
alienation from social world
Substantial social support predicts recovery from
depression
Integrative Model of Mood Disorders
 Shared Biological Vulnerability
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Overactive neurobiological response to stress
 Exposure to Stress
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Activates hormones that affect neurotransmitter systems
Turns on certain genes
Affects circadian rhythms
Activates dormant psychological vulnerabilities (i.e.,
negative thinking)
Contributes to sense of uncontrollability
Fosters a sense of helplessness and hopelessness
 Social and Interpersonal Relationships/Support are
Moderators
Challenges to Understanding Etiology
 Diagnostic ambiguity – one disorder or many?
Distinct from anxiety?
 Complex interactivity of biological influences
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Endocrine responses and genetic expression
Interaction of endocrine and neurotransmitter systems
Interaction of different neurotransmitter systems
 Acute vs. delayed responses to biological
interventions
 Cause vs. effect