Chapter 16: Psychological Disorders Flashcards
Psychological Disorders
A pattern of behavioral or psychological symptoms that impact multiple life areas and/or create distress for the person experiencing these symptoms.
DSM-IV: approximately 26.2 million Americans over age of 18 meet criteria for a psychological disorder (2005).
Schizophrenia
“Split Mind”
Disturbances in reason, emotion, perception, social relationships.
Loss of contact with reality.
Inability to function in daily life.
Positive symptoms: –Hallucinations –Delusions & Paranoia –Disorganized speech (e.g., word salad) –Disorganized behavior Negative symptoms –Social and emotional withdrawal –Absence of normal cognition or affect (e.g., flat affect, poverty of speech) Cognitive symptoms –Poor "executive functioning" –Inability to sustain attention –Problems with working memory
Concordance Rate: Risk increases with genetic similarity.
Many genes, on many different chromosomes, contribute to Schizophrenia.
~1% of world’s population
2.5 million Americans in a given year.
Equally split between genders, males have earlier onset (18-25, usually).
Schizophrenia:
Positive symptoms
–Hallucinations
–Delusions & Paranoia
–Disorganized speech (e.g., word salad)
–Disorganized behavior
Schizophrenia:
Negative symptoms
–Social and emotional withdrawal
–Absence of normal cognition or affect (e.g., flat affect, poverty of speech)
Schizophrenia:
Cognitive symptoms
–Poor “executive functioning”
–Inability to sustain attention
–Problems with working memory
Genetics of Schizophrenia
Many genes, on many different chromosomes, contribute to Schizophrenia.
Risk increases with genetic similarity
A Possible Genetic Marker
A majority of schizophrenic patients and ~50% of their relatives show abnormal intrusions of saccades in smooth pursuit tasks.
Schizophrenia:
Prenatal Factors
Low socio-economic groups Abnormal fetal development Birth complications Maternal exposure to viruses during pregnancy –Seasons
Schizophrenia:
Paternal Age
Sporadic Schizophrenia
Damaged sperm: mechanisms to ensure correct DNA translation impaired in older men resulting in “de novo” mutations.
Diathesis-Stress Model of Schizophrenia
Diathesis: Genetic predisposition & vulnerability.
Stress: Life stressors can trigger disorder.
Schizophrenia:
Brain Structure & Function Abnormalities
Enlarged ventricles. Cellular disorganization. Decreased activation of the frontal lobe. Decreased hemispherical symmetry. Adolescent loss of gray matter.
Schizophrenia:
Cellular Abnormalities in Hippocampus
Hippocampus is smaller in individual with schizophrenia
Neurons in the hippocampus are disorganized.
Schizophrenia:
Hypofrontality
Lower activity in the frontal lobes; associated with negative symptoms (e.g., social withdrawal).
Lower levels at rest and during difficult cognitive tasks.
Decreased hemispheric asymmetry; ambiguous handedness; disease might be related to a failure in normal brain lateralization.
Schizophrenia:
Adolescent Loss of Gray Matter
Cortical gray matter growth at puberty.
Gray matter loss extends into 20s.
Schizophrenic teens loose large amount of gray matter.
The Dopamine Hypothesis
Drugs that increase dopamine produce positive symptoms even in people without the disorder.
Drugs that reduce dopamine (typical neruroleptics) reduce positive symptoms.
Therefore, Schizophrenia may be caused by excess dopamine
Problems with Dopamine Hypothesis
Different time course for speed at which drugs block dopamine receptors (hours) and behavioral effects (weeks).
25% of patients do not respond to dopamine antagonists.
Atypical antipsychotic drugs (e.g. clozapine) suggest other receptors and transmitters involved (serotonin).