PSYC 273 Lecture Notes - Lecture 12: Frontal Lobe, Auditory Hallucination, Mental Disorder
Chapter 12 Notes
Toll of psychiatric disorders is huge.
• Psychiatric disorders are diagnosed based on behaviors and feelings.
• Diagnostic and Statistical Manual of Mental Disorders (DSM-5): provides a standardized
system for diagnosing and classifying the major psychiatric illnesses according to current
knowledge.
• More prevalent in females and students in higher education, but for males, drugs and
alcohol are more common problems.
• Early people submitted suffered from Paralytic dementia: thought to be caused by weak
character, but found to be caused by syphilis.
o Delusions: a false belief that is strongly held in spite of contrary evidence.
o Grandiosity.
o Euphoria.
o Poor judgement.
o Impulsive behavior.
o Disordered thoughts.
o Physiological signs.
Schizophrenia is a major neurobiological challenge in psychiatry.
• Schizophrenia: a severe psychopathological disorder characterized by negative
symptoms such as emotional withdrawal and flat affect, and by positive symptoms such
as hallucinations and delusions.
o Affects about 1% of the population.
• Schizophrenia is characterized by an unusual array of symptoms.
o Typically characterized by:
▪ Auditory hallucinations (perception).
▪ Highly personalized delusions.
▪ Changes in affect (emotion).
o Positive Symptoms: an abnormal behavior state that are absent in the normal
population.
▪ Examples include hallucinations, delusions, and excited motor behavior.
o Negative Symptoms: an abnormality that reflects insufficient functioning that is
normally seen in the regular population.
▪ Examples include, emotional and social withdrawal, attention deficits,
memory problems, reduced conversation, and blunted affect.
▪ Dissociative Thinking: impaired logical thought, disturbed thought
process and difficulty relating to events.
o Cognitive Impairment.
o Current Symptoms:
▪ Psychosis: hallucinations, delusions, and disorganization of speech and
thought.
▪ Emotional Symptoms: depression and reduced emotional expression.
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▪ Motivational Impairment.
▪ Cognitive Impairments: memory, attention, and social perception.
• Schizophrenia has a heritable component.
o Family studies.
▪ Multiple genes involved.
▪ Heredity shown in parents and siblings. Family members that are closer in
lineage to the person with schizophrenia are more likely to also have
schizophrenia.
o Adoption studies.
▪ Confirm strong genetic factor to schizophrenia.
o Twin studies.
▪ Concordance: sharing of characteristics by both individuals of a pair of
twins.
• Monozygotic= identical twins= high concordance.
o Ol aout 50%, so gees a’t e the ol eplaatio.
• Dizygotic= fraternal twins (only have 50% of the same gene) =
lower concordance.
▪ Show that schizophrenia has biological and environmental origins.
o Individual genes. Wh a’t e just test soeoe’s DNA.
▪ Over 100 genes INFLUENCE development, but do not cause.
• Glutamate, dopamine, and norepinephrine.
• Cellular Metabolism
• Genes involved in growth and changes of neurons
(neuroplasticity).
▪ Scattered across many different chromosomes.
▪ Epigenetic Factor: paternal age: older men are more likely to have kids
with schizophrenia.
▪ Stress can be a cause.
▪ Environmental factors + genetics = could be schizophrenia.
▪ Complicated genetics: genetic and epigenetic factors might influence
development.
• An integrative model of schizophrenia emphasizes the interaction of multiple factors.
o Stress in the transition to adulthood.
o Stress of city living.
o Prenatal stress.
▪ Season Birth Effect: mothers are more likely to catch a cold in the winter.
▪ Incompatible blood types.
▪ Maternal diabetes.
▪ Low birth weight.
o Relatively minor stress + genetics = could be schizophrenia.
• The brains of some patients with schizophrenia show structural and functional changes.
o There are consistent anatomical differences in the brains of many patients with
schizophrenia.
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o Ventricular abnormalities.
▪ Enlarged cerebral cortex.
• Enlarged ventricles. Come at the expense of brain tissue.
o DISC1: could cause enlarged ventricles. The protein is
involved in neurite outgrowth and cortical development
through its interaction with other proteins.
o Due to hippocampus and amygdala.
o Cortical abnormalities.
▪ Different structure and function of corpus callosum.
▪ Accelerated loss of gray matter.
o Differences in brain activity.
▪ Frontal cortex activity differences?
▪ Hypofrontality Hypothesis: the idea that schizophrenia may reflect
underactivation of the frontal lobes.
• PET scans: whereas controls have about equal activation of frontal
and posterior lobes, in schizophrenia patients there is more
activation in the posterior than frontal lobes.
• Disconcordant: reduced frontal blood flow only affected in one
twin.
• Effective drugs increase activity of frontal lobe.
• Frontal cortex neurons show reduced dendritic spines with
schizophrenia patients.
• Cognitive tasks: WCST prefrontal activation is not greater than
baseline, unlike controls.
• Antipsychotic medications revolutionized the treatment of schizophrenia.
o Lobotomy: the surgical separation of a portion of the frontal lobes from the rest
of the brain, once used as a treatment for schizophrenia and many other
ailments.
o Long term effects of antipsychotic drugs.
▪ Dyskinesia: difficulty or distortion in voluntary movement.
▪ Tardive Dyskinesia: a disorder associated with typical antipsychotic use,
and characterized by involuntary movements, especially of the face and
mouth.
• Ex: cute old lady in book.
▪ Supersensitivity Psychosis: a eaggerated reoud pshosis that
may emerge when doses of antipsychotic medication are reduced.
o The dopamine hypothesis.
▪ Antipsychotic (Neuroleptic): any of a class of drugs that alleviate
symptoms of schizophrenia, typically by blocking dopamine receptors.
▪ Dopamine Hypothesis: the idea that schizophrenia results from either
excessive levels of dopamine or dopamine receptors.
• Evidence:
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Document Summary
Come at the expense of brain tissue: disc1: could cause enlarged ventricles. D2 receptor antagonism that characterizes the typical antipsychotics. Makes people feel dissociated from themselves and their environment: psychotomimetic: a drug that induces a state resembling schizophrenia, ketamine: a dissociative anesthetic drug, similar to pcp, that acts as an. Many who are stopped from committing this act do not go on to attempt suicide again. Increased amygdala and pfc activity (fear and executive functioning): decreased parietal/ posterior temporal cortex and anterior cingulate (attention related areas). Inheritance is an important determinant of depression: the brain changes with depression, decreases activity in the posterior temporal cortex and in the anterior cingulate cortex (impacted in attention). Inhibits the enzyme that breaks down monoamines: monoamines include: norepinephrine, dopamine, serotonin, etc. , says that depressed people did get enough mao, so it causes. Inhibit monoamine reuptake: selective serotonin reuptake inhibitor (ssri): an antidepressant drug that blocks the reuptake of transmitter at serotonergic synapses.
