Psychopathology: Biological Bases of Behavioral Disorders

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Psychopathology Biological Bases of Behavioral
Disorders

• Mental Disorders SZ, Depression, BPD
• Anxiety Disorders General, PTSD, OCD
• Infectious proteins (prions)

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Epidemiological Studies of Psychiatric Disorders

• 20 (6-month period)
• 50 in lifetime
• Early in life Schizophrenia (1-2 prevalence)
• Midlife (25-44) Depression
• Old age Cognitive Disorders (65 and older)

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History of Schizophrenia (SZ)

• Syphilis and psychosis
• Emil Kraepelin dementia praecox
• Eugen Blueler Schizophrenia (split brain)
• Core symptom dissociative thinking
• Kurt Schneider
• Positive symptoms hallucinations, delusions,
  excited motor behavior
• Negative symptoms slow and impoverished thought
  and speech, emotional and social withdrawal,
  blunted affect

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Heritability of SZ

• 50 MZ twin concordance / 17 DZ
• 6-17 first-degree relatives
• Adoptions studies
• Greater prevalence among biological relatives
• Mode of transmission complex
• Genetic component
• Spread across all but 8 of 23 chromosomes
• Gene for ACH, NMDA, GABA and ACh receptor
  regulation, COM-T (DA regulation)
• Environmental stressor(s)

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Anatomy of SZ

• Ventricular enlargement
• Disoriented hippocampal cells
• Degree R2 with severity of symptoms
• 2nd trimester exposure to influenza / temperature
  of gestating fetus
• Early cell development
• Regional anatomical abnormalities
• Adolescent SZs loose more gray matter and at
  faster rate
• Shrinkage of cerebellar vermis
• Thicker corpus callosum
• Abnormal fetal cell migration to prefrontal
  cortex
• Functional maps
• Frontal cortex hypofrontality in general and in
  response to WISC
• Antipsychotics alleviate
• Neurochemical changes
• Amphetamine psychosis

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Depression

• Prolonged unhappy mood loss of interests,
  energyand appetite age of onset (typical) 40
  yr, hereditary component
• Bipolar Disorder
• younger age of onset cycles of mania and
  depression
• lithium effective therapy
• 2-3 times more common in women
• 80 of suicides depressed individuals
• Lower 5-HT (contributes to depression in PD)
• Higher cortisol levels (contributes to
  CushingsDisease)

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Functional Maps / Neurochemistry of Depression

• Increased frontal cortex amygdala activity
• Decreased parietal and posterior temporal
  cortexactivity
• Monoamine theory
• Decreased 5-HTergic and noradrenergic activity
• Antidepressants
• Restore monoamine levels
• ECT
• Drugs that deplete monoamines exacerbate
  depression

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Depression and Adrenal Function

• Increased cortisol
• HPA axis unresponsive to feedback
• Dexamethasone suppression test fails
• Decreased neurotrophic factors (BDNF 5-HT and
  NE agonist increase)

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Depression and Gender

• 2-fold difference (women v. men)
• Psychosocial
• Social discrimination, low self assertion/ esteem
  depression
• Learned-helplessness
• Endocrine physiology no strong evidence
• Before menstruation
• Contraceptive pill use
• Following childbirth
• Menopause
• Amish women and men show same prevalence
• Alcohol banished men in typical US society mask
  depression w/ alcohol consumption?

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Depression and Sleep

• Decreased stages 3 and 4 SWS
• Increased stages 1 and 2 SWS
• Shortened REM onset / REM bouts more rigorous
• REM sleep deprivation improves depression

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Physiological Markers andTreatment for Anxiety
Disorders

• Temporal lobe abnormalities
• Increased parahippocampal basal activity
• High oxygen metabolism
• Anxiolytics pharmacotherapy
• Most common class - benzodiazepines

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Post Traumatic Stress Disorder

• Traumatic experience
• Witnessing, participating in mass killings
• Severe abuse
• Fear conditioning and behavioral sensitization
• Previously neutral stimuli evoke response
• Autonomic
• Fear, trembling
• Vivid memories
• Evoked by stressful circumstances

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Treatment for PTSD - I

• Cognitive-behavioral therapy (CBT)
• Work with cognition to change emotions
• Exposure therapy through imagery
• Flooding (all-at-once confrontation)
• Desensitization (gradual exposure)
• Learning coping skills
• Group Treatment
• Sharing traumatic narrative
• Sharing coping mechanisms

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Obsessive Compulsive Disorder

• Obsessions or compulsions
• Intrusive thoughts compelled to act on
• Insight
• Time-consuming
• Treatment
• CBT
• Exposure
• Pharmacotherapy
• Tricyclics (increaase monoamine)
• SSRIs (increase 5-HT)

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Prions, Mad Cows and Creutzfeldt-Jakob Disease

• Normal protein takes on new, abnormal shape -
  prions
• Induces other proteins to fold as well
• Leads to brain degeneration
• Bovine spongiform encephalopathy (BSE, mad cow
  disease
• Creutzfeldt-Jakob Disease ingested cows with
  BSE in Britons
• Treatment experimental / early stages of
  investigation and effective treatment

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Take Home Message

• Psychobiological approaches to understanding and
  treating psychiatric decline
• Schizophrenia
• Depression
• Anxiety Disorders
• Mad Cow Disease