Chapter 14 Psychological Disorders

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Chapter 14Psychological Disorders

• Module 14.2

• Mood Disorders

Module 14.3
Schizophrenia
Module 14.4
Autism Spectrum Disorders
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Mood Disorders
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Mood Disorders

• Unipolar disorder is characterized by
  alternating states of normality and depression.
• Symptoms include

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Depression

• Similar symptoms can result from
• hormonal problems
• head injuries
• brain tumors
• other illnesses

• Often comorbid with other disorders such as
• schizophrenia
• substance abuse
• anxiety
• Parkinsons disease
• Occurs at any age
• 10 lifetime prevalence

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Depression

• Childhood depression is equally common in both
  boys and girls.
• After puberty, depression is twice as common in
  females.
• The finding is consistent across cultures,
  suggesting a biological factor.

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Genetics of Depression

• Studies of twins and adopted children suggest a
  moderate degree of heritability.
• Risk is elevated if one has a relative with
  early-onset depression (before age 30).

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Genetics of Depression

• One gene has been identified that controls the
  serotonin transporter protein.
• Protein controls the ability of the axon to
  reabsorb the neurotransmitter after its release.
• Two short forms of the gene are associated with
  an increased likelihood of depression after
  stressful events.
• Perhaps alters the way people react to stressful
  events.

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Depression and Hormones

• Hormones are also involved with depression.
• A likely trigger for an episode of depression is
  stress and the release of the hormone cortisol.
• Prolonged elevated levels exhaust the bodys
  energies, impair sleep and the immune system.
• Set the stage for an episode of depression.

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Postpartum Depression

• Occurs after giving birth.
• Affects about 20 of women and most recover
  quickly.
• More common among women who
• have suffered depression at other times.
• experience sever discomfort during the times
  around menstruation.
• May be associated with a drop in estradiol and
  progesterone levels.

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Depression and Brain Activity

• Depression is associated with
• Decreased activity in the left prefrontal cortex
• Increased activity in the right prefrontal cortex
• Many people become seriously depressed after
  left-hemisphere damage.
• Occasionally, people with right hemisphere damage
  become manic.

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Treatment of Depression Antidepressant Drugs

• Categories of antidepressant drugs include
• Tricyclics prevent the presynaptic neuron from
  reabsorbing serotonin, dopamine, or
  norepinephrine
• Selective Serotonin Reuptake Inhibitors (SSRIs)
  block the reuptake of the neurotransmitter
  serotonin

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Treatment of Depression Antidepressant Drugs

1. Monoamine Oxidase Inhibitors (MAOIs) block the
   enzyme monoamine oxidase that metabolizes
   serotonin into an inactive form
2. Atypical antidepressants work by inhibiting the
   reuptake of dopamine and to some extent,
   norepinephrine but not serotonin.

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Treatment of Depression Electroconvulsive
Therapy (ECT)

• electrically induced seizure used for the
  treatment of severe depression
• used with patients who have not responded to
  antidepressant medication or who are suicidal
• fast-acting, but effects diminish rapidly
• best used in conjunction with other forms of
  therapy

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Treatment of Depression Electroconvulsive
Therapy (ECT)

• Side effects include memory loss.
• Memory loss can be minimized if shock is
  localized to the right hemisphere.
• increases the proliferation of new neurons in the
  hippocampus
• alters expression of at least 120 genes in the
  hippocampus and frontal cortex

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Treatment of Depression Transcranial Magnetic
Stimulation

• an intense magnetic field is applied to the
  scalp, to stimulate the neurons
• moderately effective

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Treatment of Depression Disruption of Sleep
Patterns

• Disruption of sleep patterns is common in
  depression.
• Typically fall asleep but awaken early and are
  unable to get back to sleep.
• Enter REM sleep within 45 minutes and have an
  increased average number of eye movements during
  REM sleep.
• Sleep pattern disruption also increases the
  likelihood of depression.

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Treatment of Depression Disruption of Sleep
Patterns

• A night of total sleep deprivation is the
  quickest known method of relieving depression.
• Half who experience relief become depressed again
  after the next nights sleep.
• Therefore, often best used in conjunction with
  other therapies

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Bipolar Disorder

• Bipolar disorder (manic-depressive disorder) is
  characterized by the alternating states of
  depression and mania.
• Mania - restless activity, excitement, laughter,
  self-confidence, rambling speech, and loss of
  inhibition.

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Bipolar Disorder

• Bipolar disorder I - characterized by full blown
  episodes of mania.
• Bipolar disorder II - characterized by much
  milder manic phases, called hypomania, of which
  anxiety and agitation are the primary symptoms.
• Affects approximately 1 of people.
• Average age of onset is in the early 20s.
• Brains use of glucose increases during periods
  of mania and decreases during periods of
  depression.

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Genetics of Bipolar Disorder

• Twin studies suggest monozygotic twins share a
  50 concordance rate.
• Dizygotic twins, brothers, sisters or children
  share a concordance rate of 5-10.
• Several genes are somewhat more common in people
  with the disorder.
• Genes simply increase the risk but do not cause
  the disorder.

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Treatments for Bipolar Disorder
These chemicals/drugs are used to stabilize mood

• Lithium - a salt that prevents relapse in mania
  or depression
• Anticonvulsant drugs such as valproate (depakote)
  and carbamazepine
• Usually prescribed for bipolar II.

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Seasonal Affective Disorder (SAD)

• form of depression that regularly occurs during a
  particular season.
• Patients with SAD have phase-delayed sleep and
  temperature rhythms most depressed people have
  phase-advanced patterns.
• Treatment often includes the use of very bright
  lights.
• Most likely explanation is that the light affects
  serotonin synapses and alters circadian rhythms.

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Schizophrenia

• Schizophrenia is a disorder characterized by
  deteriorating ability to function in every day
  life and some combination of the following
  symptoms

• Hallucinations abnormal sensory experiences
• Delusions unfounded beliefs
• Disorganized speech rambling
• or incoherent
• Grossly disorganized behavior
• Weak or absent signs of emotion,
• speech, and socialization
• Inappropriate emotional
• expression
• Thought disorder difficulty
• using and understanding
• abstract concepts

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Schizophrenia Inappropriate Emotional Expression

• Positive symptoms are behaviors that are present
  that should not be present.
• hallucinations
• delusions
• disorganized speech

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Schizophrenia Inappropriate Emotional Expression

• Negative symptoms are behaviors that are absent
  that should be present, including
• weak social interaction
• lack of emotional expression
• speech deficit
• working memory deficit
• Negative symptoms are usually stable over time
  and difficult to treat.

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Schizophrenia Incidence Rates

• Schizophrenia affects about 1 of the population
  and ranges in severity.
• Can be either acute or chronic
• Acute - condition has a sudden onset and good
  prospect for recovery.
• Chronic - condition has a gradual onset and a
  long-term course.

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Schizophrenia Incidence Rates

• Occurs in all parts of the world, but is 10 to
  100 times more common in the United States and
  Europe than in third-world countries.
• More common in men than in women by a ratio of
  about 7 to 5.
• More severe and earlier age of onset for men
  (early 20s versus late 20s).
• Likelihood increases as the age of the father
  increases.

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Schizophrenia Genetics

• Twin studies suggest a genetic component.
• Monozygotic twins have a much higher concordance
  rate (agreement) than dizygotic twins.
• But monozygotic twins only have a 50 concordance
  rate.
• Greater similarity between dizygotic twins than
  siblings suggests a prenatal/postnatal
  environmental effect.

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Schizophrenia Genetics

• Attempt to link adult-onset schizophrenia to an
  identified gene have provided inconsistent
  results.
• Schizophrenia most likely results from
  environmental factors in addition to biological
  factors.

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SchizophreniaNeurodevelopmental Hypothesis

• suggests abnormalities in the prenatal or
  neonatal development of the nervous system.
• Leads to subtle abnormalities of brain anatomy
  and major abnormalities in behavior.
• Abnormalities could result from genetics,
  difficulty during birth, or a combination of
  both.

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SchizophreniaNeurodevelopmental Hypothesis

• Supporting evidence includes
• Several kinds of prenatal or neonatal
  difficulties are linked to later schizophrenia.
• People with
• schizophrenia have
• minor brain
• abnormalities that
• originate early in life.
• Abnormalities of early
• development could
• impair behavior in
• adulthood.

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SchizophreniaNeurodevelopmental Hypothesis

• Prenatal risk factors increasing the likelihood
  of schizophrenia include
• Poor nutrition of the mother during pregnancy.
• Premature birth.
• Low birth weight.
• Complications during delivery.
• Head injuries in early childhood are also linked
  to increased incidence of schizophrenia.

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SchizophreniaNeurodevelopmental Hypothesis

• Mother/child blood type differences increase the
  likelihood of schizophrenia.
• If the mother has a Rh-negative blood type and
  the baby is Rh-positive, the child has about
  twice the probability of developing schizophrenia.

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SchizophreniaNeurodevelopmental Hypothesis

• The season-of-birth effect refers to the tendency
  for people born in winter to have a slightly (5
  to 8) greater probability of developing
  schizophrenia.
• More pronounced in latitudes far from the
  equator.
• Might be explained by complications of delivery,
  nutritional factors, or increased likelihood of
  viral infections

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Schizophrenia Brain Abnormalities

• Schizophrenia is associated with mild brain
  abnormalities
• Less than average gray and white matter
• Strongest deficits found in the left temporal and
  frontal lobe of the cortex
• Larger than normal ventricles
• Smaller than normal hippocampus
• Schizophrenics have deficits in working memory.

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Schizophrenia Development

• Schizophrenia typically develops after the age of
  20 but many show sign at an earlier age.
• Deficits in attention, memory and impulse
  control.
• Prefrontal cortex damage may not show signs of
  damage until later.
• Structure matures slowly and does not do much at
  an earlier age.
• Neurodevelopmental hypothesis is thus plausible
  but not firmly established.

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Schizophrenia Treatment

• Antipsychotic/neuroleptic drugs are drugs that
  tend to relieve schizophrenia and similar
  conditions.
• Chlorpromazine (thorazine) is a drug used to
  treat schizophrenia that relieves the positive
  symptoms of schizophrenia.
• Relief usually experienced 2-3 weeks after taking
  the drug, which must be taken indefinitely.

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Schizophrenia Treatment

• Two chemical families of drugs used to treat
  schizophrenia include
• Phenothiazines - includes chlorpromazine
• Butyrophenones - includes halperidol (Haldol)
• Both drugs block dopamine synapses.

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Dopamine Hypothesis of Schizophrenia

• suggests that schizophrenia results from excess
  activity at dopamine synapses in certain areas of
  the brain.
• Substance-induced psychotic disorder is
  characterized by hallucinations and delusions
  resulting from repeated large doses of
  amphetamines, methamphetamines, or cocaine.
• Each prolongs activity of dopamine at the
  synapse, providing further evidence for dopamine
  hypothesis.

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Glutamate Hypothesis of Schizophrenia

• suggests the problem relates partially to
  deficient activity at glutamate receptors
• especially in the prefrontal cortex
• Schizophrenia is associated with lower than
  normal release of glutamate and fewer receptors
  in the prefrontal cortex and hippocampus.

• Support comes from the effects of phencyclidine
  (PCP/angel dust).
• Inhibits the NMDA glutamate receptors.
• Produces positive and negative symptoms at high
  doses.

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Schizophrenia Treatment

• The mesolimbocortical system is a set of neurons
  that project from the midbrain tegmentum to the
  limbic system.
• Site where drugs that block dopamine synapses
  produce their benefits.
• Drugs also block dopamine in the mesostriatal
  system, which project to the basal ganglia.
• Result is tardive dyskinesia, characterized by
  tremors and other involuntary movements.

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Schizophrenia Treatment

• Second-generation antipsychotics (atypical
  antipsychotics) are a class of drugs used to
  treat schizophrenia but seldom produce movement
  problems.
• Examples clozapine, amisulpride, risperidone,
  olanzapine, aripiprazole.
• More effective at treating the negative symptoms
  and are now more widely used.

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Schizophrenia

• Schizophrenia cannot be explained by a single
  gene or single transmitter.
• Dopamine and glutamate may play important roles
  in schizophrenia to different degrees in
  different people.
• Schizophrenia involves multiple genes and
  abnormalities in dopamine, glutamate, serotonin
  and GABA.

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Autism Spectrum Disorders

• Primary characteristics
• Deficits in social and emotional exchange
• Deficits in gestures, facial expression and other
  nonverbal communication
• Repetitive behaviors
• Resistance to change in routine
• Unusually weak or strong emotional reactions

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Autism Spectrum Disorders

• Worldwide prevalence estimated at 1 in 160 people
• More common in boys than girls

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Autism Spectrum Disorders

• Often comorbid with Attention Deficit Disorder
  (ADD)
• Can involve cerebellum, resulting in movement
  deficit

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Autism Spectrum Disorders

• Many genes have been linked to autism, but no
  single gene is found in a high percentage of
  people with autism
• Most cases probably result from new mutations or
  microdeletions in multiple genes.