Biological Bases of Psychological Disorders (7A) - MCAT Psychological and Social Foundations
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What is the core neurobiological mechanism of benzodiazepines?
What is the core neurobiological mechanism of benzodiazepines?
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Increase GABA-A receptor activity (greater Cl⁻ influx). Enhances inhibitory signaling by opening chloride channels.
Increase GABA-A receptor activity (greater Cl⁻ influx). Enhances inhibitory signaling by opening chloride channels.
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What is the core neurobiological mechanism of typical (first-generation) antipsychotics?
What is the core neurobiological mechanism of typical (first-generation) antipsychotics?
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D$_2$ receptor antagonism (dopamine blockade). Blocks dopamine receptors, reducing positive symptoms.
D$_2$ receptor antagonism (dopamine blockade). Blocks dopamine receptors, reducing positive symptoms.
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What is the core neurobiological mechanism of lithium in bipolar disorder (high-level description)?
What is the core neurobiological mechanism of lithium in bipolar disorder (high-level description)?
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Mood stabilizer that modulates intracellular signaling (e.g., second messengers). Affects multiple pathways including GSK-3 and inositol systems.
Mood stabilizer that modulates intracellular signaling (e.g., second messengers). Affects multiple pathways including GSK-3 and inositol systems.
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What is the most common neuroimaging finding in major depressive disorder regarding the prefrontal cortex?
What is the most common neuroimaging finding in major depressive disorder regarding the prefrontal cortex?
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Decreased activity in prefrontal cortical regions. Hypoactivity impairs emotional regulation and executive function.
Decreased activity in prefrontal cortical regions. Hypoactivity impairs emotional regulation and executive function.
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Which sleep abnormality is classically associated with major depressive disorder?
Which sleep abnormality is classically associated with major depressive disorder?
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Shortened REM latency (earlier onset of REM sleep). REM occurs sooner after sleep onset in depressed patients.
Shortened REM latency (earlier onset of REM sleep). REM occurs sooner after sleep onset in depressed patients.
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What is epigenetics in the context of psychological disorders?
What is epigenetics in the context of psychological disorders?
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Environment-driven changes in gene expression without DNA sequence change. Stress/trauma can alter gene activity via methylation/histones.
Environment-driven changes in gene expression without DNA sequence change. Stress/trauma can alter gene activity via methylation/histones.
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Which option best describes the monoamine hypothesis of depression?
Which option best describes the monoamine hypothesis of depression?
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Depression relates to reduced monoamine signaling (5-HT, NE, DA). Deficient serotonin/norepinephrine/dopamine causes depressive symptoms.
Depression relates to reduced monoamine signaling (5-HT, NE, DA). Deficient serotonin/norepinephrine/dopamine causes depressive symptoms.
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What is the core neurobiological mechanism of SSRIs?
What is the core neurobiological mechanism of SSRIs?
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Inhibit serotonin reuptake, increasing synaptic 5-HT. Blocks SERT transporter, prolonging serotonin's synaptic action.
Inhibit serotonin reuptake, increasing synaptic 5-HT. Blocks SERT transporter, prolonging serotonin's synaptic action.
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Which neurotransmitter is most associated with alertness and arousal and is targeted by SNRIs?
Which neurotransmitter is most associated with alertness and arousal and is targeted by SNRIs?
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Norepinephrine. Part of fight-or-flight response; dysregulated in anxiety/depression.
Norepinephrine. Part of fight-or-flight response; dysregulated in anxiety/depression.
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Which neurotransmitter is most associated with mood regulation and is targeted by SSRIs?
Which neurotransmitter is most associated with mood regulation and is targeted by SSRIs?
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Serotonin (5-HT). Low serotonin linked to depression; SSRIs block its reuptake.
Serotonin (5-HT). Low serotonin linked to depression; SSRIs block its reuptake.
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Which neurotransmitter is classically linked to reward, motivation, and positive symptoms of schizophrenia?
Which neurotransmitter is classically linked to reward, motivation, and positive symptoms of schizophrenia?
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Dopamine. Excess dopamine activity linked to hallucinations/delusions.
Dopamine. Excess dopamine activity linked to hallucinations/delusions.
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Which brain region is most associated with executive control and impulse regulation?
Which brain region is most associated with executive control and impulse regulation?
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Prefrontal cortex. Top-down control center for planning and inhibiting behaviors.
Prefrontal cortex. Top-down control center for planning and inhibiting behaviors.
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Which brain region is most associated with fear conditioning and threat detection?
Which brain region is most associated with fear conditioning and threat detection?
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Amygdala. Processes emotional salience and triggers fear responses.
Amygdala. Processes emotional salience and triggers fear responses.
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What is the diathesis–stress model of psychological disorders?
What is the diathesis–stress model of psychological disorders?
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Disorder risk = predisposition (diathesis) + environmental stressors. Combines genetic vulnerability with life stress to explain disorder onset.
Disorder risk = predisposition (diathesis) + environmental stressors. Combines genetic vulnerability with life stress to explain disorder onset.
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Which study design most directly separates genetic from shared environmental effects?
Which study design most directly separates genetic from shared environmental effects?
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Twin studies comparing monozygotic versus dizygotic concordance. MZ twins share 100% DNA; DZ share 50%, allowing genetic effect isolation.
Twin studies comparing monozygotic versus dizygotic concordance. MZ twins share 100% DNA; DZ share 50%, allowing genetic effect isolation.
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What does heritability estimate in behavioral genetics represent?
What does heritability estimate in behavioral genetics represent?
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Proportion of trait variance in a population due to genetic variation. Measures how much genes (vs environment) contribute to individual differences.
Proportion of trait variance in a population due to genetic variation. Measures how much genes (vs environment) contribute to individual differences.
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Which brain structure shows reduced volume most classically associated with PTSD and chronic stress exposure?
Which brain structure shows reduced volume most classically associated with PTSD and chronic stress exposure?
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Hippocampus. Stress hormones damage hippocampal neurons over time.
Hippocampus. Stress hormones damage hippocampal neurons over time.
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What is the HPA axis response pattern commonly associated with chronic stress and depression?
What is the HPA axis response pattern commonly associated with chronic stress and depression?
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Hyperactive HPA axis with elevated cortisol. Chronic stress dysregulates hypothalamic-pituitary-adrenal feedback.
Hyperactive HPA axis with elevated cortisol. Chronic stress dysregulates hypothalamic-pituitary-adrenal feedback.
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Which neurotransmitter is most associated with excitatory signaling and NMDA receptor hypotheses in schizophrenia?
Which neurotransmitter is most associated with excitatory signaling and NMDA receptor hypotheses in schizophrenia?
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Glutamate. Primary excitatory NT; hypofunction may contribute to psychosis.
Glutamate. Primary excitatory NT; hypofunction may contribute to psychosis.
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Which neurotransmitter is most associated with inhibitory signaling and anxiety reduction (target of benzodiazepines)?
Which neurotransmitter is most associated with inhibitory signaling and anxiety reduction (target of benzodiazepines)?
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GABA. Primary inhibitory NT; benzos enhance its calming effects.
GABA. Primary inhibitory NT; benzos enhance its calming effects.
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What is the primary mechanism of action of SSRIs?
What is the primary mechanism of action of SSRIs?
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Inhibit serotonin reuptake transporter to increase synaptic $5$-HT. Blocks SERT protein, preventing serotonin removal from synapse.
Inhibit serotonin reuptake transporter to increase synaptic $5$-HT. Blocks SERT protein, preventing serotonin removal from synapse.
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What is epigenetics as it relates to psychological disorders?
What is epigenetics as it relates to psychological disorders?
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Environmental effects on gene expression without changing DNA sequence. Modifies gene activity via methylation/histones, not mutations.
Environmental effects on gene expression without changing DNA sequence. Modifies gene activity via methylation/histones, not mutations.
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What is concordance in the context of twin studies of psychological disorders?
What is concordance in the context of twin studies of psychological disorders?
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Probability both twins show the same trait or disorder. If one twin has disorder, concordance = chance the other does too.
Probability both twins show the same trait or disorder. If one twin has disorder, concordance = chance the other does too.
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What is the primary mechanism of action of benzodiazepines in anxiety treatment?
What is the primary mechanism of action of benzodiazepines in anxiety treatment?
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Increase $GABA_A$ receptor activity (increase inhibitory signaling). Enhances GABA's inhibitory effect, reducing neural excitation.
Increase $GABA_A$ receptor activity (increase inhibitory signaling). Enhances GABA's inhibitory effect, reducing neural excitation.
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Which neurotransmitter is most associated with reward pathways and positive symptoms of schizophrenia?
Which neurotransmitter is most associated with reward pathways and positive symptoms of schizophrenia?
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Dopamine. Hyperactivity causes hallucinations; hypoactivity causes anhedonia.
Dopamine. Hyperactivity causes hallucinations; hypoactivity causes anhedonia.
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Which term describes one gene influencing multiple traits, potentially linking a gene to several disorders?
Which term describes one gene influencing multiple traits, potentially linking a gene to several disorders?
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Pleiotropy. Single gene affects multiple phenotypes simultaneously.
Pleiotropy. Single gene affects multiple phenotypes simultaneously.
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Which neurotransmitter is classically increased at the synapse by SSRIs to treat depression and anxiety?
Which neurotransmitter is classically increased at the synapse by SSRIs to treat depression and anxiety?
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Serotonin ($5$-HT). SSRIs block reuptake, increasing synaptic serotonin levels.
Serotonin ($5$-HT). SSRIs block reuptake, increasing synaptic serotonin levels.
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What does heritability ($h^2$) represent in behavioral genetics?
What does heritability ($h^2$) represent in behavioral genetics?
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Proportion of trait variance due to genetic differences in a population. Measures genetic contribution to phenotypic variation in populations.
Proportion of trait variance due to genetic differences in a population. Measures genetic contribution to phenotypic variation in populations.
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Which neurotransmitter deficit is most associated with Alzheimer disease and impaired memory?
Which neurotransmitter deficit is most associated with Alzheimer disease and impaired memory?
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Acetylcholine deficiency. Cholinergic neurons degenerate, impairing memory formation.
Acetylcholine deficiency. Cholinergic neurons degenerate, impairing memory formation.
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Which study design most directly estimates genetic influence by comparing MZ vs DZ twins?
Which study design most directly estimates genetic influence by comparing MZ vs DZ twins?
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Twin study (MZ vs DZ concordance comparison). MZ twins share 100% genes; DZ share 50%, revealing genetic effects.
Twin study (MZ vs DZ concordance comparison). MZ twins share 100% genes; DZ share 50%, revealing genetic effects.
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