MCAT Psychological Social Foundations Flashcards: 7a Biological Bases Psychological Disorders

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This deck focuses on 7a Biological Bases Psychological Disorders, giving you a quick way to review the definitions, rules, and examples that matter most for MCAT Psychological Social Foundations.

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Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Which option best matches the symptom type in schizophrenia: hallucinations and delusions are what type?

Answer: Positive symptoms. Added experiences (hallucinations/delusions) beyond normal function.

Flashcard 2: What is the diathesis-stress model of psychological disorders?

Answer: Disorder risk = predisposition plus environmental stressors. Combines genetic vulnerability with environmental triggers.

Flashcard 3: What is the key mechanism of typical (first-generation) antipsychotics?

Answer: D$_2$ receptor antagonism. Blocks dopamine D$_2$ receptors to reduce positive symptoms but may cause extrapyramidal side effects.

Flashcard 4: Which brain circuit is most associated with OCD pathophysiology?

Answer: Cortico-striato-thalamo-cortical (CSTC) loop. Dysfunction in this loop impairs inhibition of intrusive thoughts, central to OCD symptoms.

Flashcard 5: What does heritability ($h^2$) represent in behavioral genetics?

Answer: Proportion of trait variance due to genetic differences in a population. Measures genetic contribution to phenotypic variation in populations.

Flashcard 6: What is gene-environment interaction in the context of psychological disorders?

Answer: Environmental effects on disorder risk depend on genotype (and vice versa). It describes how genetic factors moderate environmental impacts on psychopathology, or vice versa, influencing disorder manifestation.

Flashcard 7: What is the primary mechanism of selective serotonin reuptake inhibitors (SSRIs)?

Answer: Inhibit serotonin reuptake (block SERT) to increase synaptic 5-HT. Blocking the serotonin transporter prolongs neurotransmitter presence in the synapse, alleviating depressive symptoms.

Flashcard 8: Identify the hormone released by the adrenal cortex as the end product of HPA-axis activation.

Answer: Cortisol. HPA activation culminates in glucocorticoid release, mediating stress effects on brain and behavior.

Flashcard 9: Which neurotransmitter is most strongly linked to positive symptoms of schizophrenia?

Answer: Dopamine (especially increased mesolimbic activity). Hyperactive dopamine pathways cause hallucinations and delusions.

Flashcard 10: Which neurotransmitter is most associated with OCD in common MCAT frameworks?

Answer: Serotonin dysregulation. Altered serotonin signaling in frontostriatal circuits contributes to obsessive thoughts and compulsions.

Flashcard 11: Which neurotransmitter is classically linked to reward and is implicated in addiction?

Answer: Dopamine. Activates reward pathways; dysregulated in substance use disorders.

Flashcard 12: What is the core neurobiological mechanism of benzodiazepines?

Answer: Increase GABA-A receptor activity (greater Cl⁻ influx). Enhances inhibitory signaling by opening chloride channels.

Flashcard 13: What is the most common neuroimaging finding in major depressive disorder regarding the prefrontal cortex?

Answer: Decreased activity in prefrontal cortical regions. Hypoactivity impairs emotional regulation and executive function.

Flashcard 14: Which movement disorder is a common extrapyramidal side effect of antipsychotics (especially typical)?

Answer: Tardive dyskinesia. Long-term D$_2$ antagonism leads to involuntary movements due to dopamine receptor upregulation.

Flashcard 15: What is the primary mechanism of action of benzodiazepines in anxiety treatment?

Answer: Increase $GABA_A$ receptor activity (increase inhibitory signaling). Enhances GABA's inhibitory effect, reducing neural excitation.

Flashcard 16: What brain region degenerates in Parkinson disease to cause dopamine loss?

Answer: Substantia nigra pars compacta. Dopaminergic neurons die, causing movement disorders.

Flashcard 17: Which neurotransmitter is most associated with depression in the monoamine hypothesis?

Answer: Serotonin (also norepinephrine). The hypothesis posits low monoamine levels cause depressive symptoms, with serotonin and norepinephrine deficits central.

Flashcard 18: What is the monoamine hypothesis of depression?

Answer: Depression involves reduced 5-HT, NE, and/or DA signaling. Links depression to deficient serotonin, norepinephrine, or dopamine.

Flashcard 19: Which epigenetic mechanism typically decreases transcription by tightening chromatin?

Answer: DNA methylation. Methyl groups on DNA compact chromatin and silence genes.

Flashcard 20: Which study design most directly separates genetic from shared environmental effects?

Answer: Twin studies comparing monozygotic versus dizygotic concordance. MZ twins share 100% DNA; DZ share 50%, allowing genetic effect isolation.

Flashcard 21: What is the primary mechanism of benzodiazepines in treating anxiety?

Answer: Increase GABA$_A$ receptor activity (increase Cl$^-$ channel opening frequency). Allosteric modulation enhances GABA binding, promoting inhibition to reduce anxiety symptoms.

Flashcard 22: Which neurotransmitter is most associated with mood regulation and is targeted by SSRIs?

Answer: Serotonin (5-HT). Low serotonin linked to depression; SSRIs block its reuptake.

Flashcard 23: Which brain structure is most strongly associated with fear processing in phobias and PTSD?

Answer: Amygdala. Central to threat detection and fear response.

Flashcard 24: Which research design best estimates genetic influence by comparing MZ vs DZ twins?

Answer: Twin study. MZ twins share 100% DNA; DZ twins share 50%, allowing genetic estimation.

Flashcard 25: What structural brain finding is commonly associated with schizophrenia?

Answer: Enlarged ventricles with reduced cortical gray matter. Brain tissue loss leads to fluid-filled space expansion.

Flashcard 26: Which neurotransmitter is the primary inhibitory transmitter implicated in anxiety and targeted by benzodiazepines?

Answer: GABA. Reduced GABAergic inhibition heightens neural excitability, contributing to anxiety; benzodiazepines enhance it.

Flashcard 27: Which basal ganglia circuit is most implicated in OCD pathophysiology?

Answer: Cortico-striato-thalamo-cortical (CSTC) loop dysfunction. Hyperactive loop creates repetitive thoughts and behaviors.

Flashcard 28: Which neurotransmitter is the primary excitatory transmitter and is implicated in schizophrenia hypotheses?

Answer: Glutamate. NMDA receptor hypofunction may contribute to psychotic symptoms.

Flashcard 29: What is the HPA axis outcome that is commonly elevated with chronic stress-related disorders?

Answer: Increased cortisol secretion. HPA axis hyperactivity releases excess stress hormone.

Flashcard 30: What is the diathesis-stress model of psychological disorders?

Answer: Disorder risk = predisposition (diathesis) + environmental stressors. Vulnerability plus stress triggers disorder onset.

Flashcard 31: Which option best describes the monoamine hypothesis of depression?

Answer: Depression relates to reduced monoamine signaling (5-HT, NE, DA). Deficient serotonin/norepinephrine/dopamine causes depressive symptoms.

Flashcard 32: What is epigenetics in the context of psychological disorders?

Answer: Environment-driven changes in gene expression without DNA change. Heritable changes in gene activity without altering DNA sequence.

Flashcard 33: Which brain structure is often hyperactive in anxiety disorders and phobias?

Answer: Amygdala. Fear center shows increased activity during threat processing.

Flashcard 34: Which sleep abnormality is classically associated with major depressive disorder?

Answer: Shortened REM latency (earlier onset of REM sleep). REM occurs sooner after sleep onset in depressed patients.

Flashcard 35: Which brain region is central for episodic memory and is often reduced in chronic PTSD or depression?

Answer: Hippocampus. Stress hormones can damage this memory-forming structure.

Flashcard 36: What is the genetic mutation pattern that causes Huntington disease?

Answer: Autosomal dominant CAG trinucleotide repeat expansion. HTT gene mutation; >40 repeats causes disease.

Flashcard 37: Identify the neurotransmitter change most consistent with the dopamine hypothesis of schizophrenia.

Answer: Increased dopaminergic signaling (especially mesolimbic). Excess dopamine activity linked to positive symptoms.

Flashcard 38: What is the core neurobiological mechanism of typical (first-generation) antipsychotics?

Answer: D$_2$ receptor antagonism (dopamine blockade). Blocks dopamine receptors, reducing positive symptoms.

Flashcard 39: What HPA-axis pattern is commonly associated with major depressive disorder?

Answer: Hyperactive HPA axis with elevated cortisol. Chronic stress causes persistent cortisol elevation.

Flashcard 40: Which neurotransmitter is most associated with alertness and is implicated in anxiety arousal?

Answer: Norepinephrine. Part of fight-or-flight response; elevated in anxiety states.

Flashcard 41: Which neurotransmitter is most associated with reward pathways and positive symptoms of schizophrenia?

Answer: Dopamine. Hyperactivity causes hallucinations; hypoactivity causes anhedonia.

Flashcard 42: Which neurotransmitter is most associated with mood regulation and SSRI treatment targets?

Answer: Serotonin. Low levels linked to depression; SSRIs block its reuptake.

Flashcard 43: What does "heritability" mean in behavioral genetics of mental disorders?

Answer: Population variance fraction attributable to genetic differences. Measures genetic contribution to trait variation in a population.

Flashcard 44: What is the diathesis-stress model of psychological disorders?

Answer: Disorder risk = predisposition (diathesis) + environmental stress. This model explains how genetic vulnerabilities interact with stressors to precipitate disorders, emphasizing multifactorial causation.

Flashcard 45: Which neurotransmitter is classically linked to schizophrenia via the dopamine hypothesis?

Answer: Dopamine. Excess dopamine activity in certain pathways contributes to hallucinations and delusions in schizophrenia.

Flashcard 46: What two protein pathologies are characteristic of Alzheimer disease?

Answer: Beta-amyloid plaques and hyperphosphorylated tau tangles. Plaques form between neurons; tangles form inside neurons.

Flashcard 47: What neurotransmitter abnormality is most associated with Huntington disease?

Answer: Decreased GABA (and decreased acetylcholine) in the striatum. Loss of inhibitory control causes involuntary movements.

Flashcard 48: What is epigenetics as it relates to psychological disorders?

Answer: Environment-driven changes in gene expression without DNA sequence change. Modifies gene activity through mechanisms like methylation, linking early life stress to long-term disorder susceptibility without altering DNA.

Flashcard 49: Which mood disorder is strongly linked to decreased serotonin and increased HPA-axis activity?

Answer: Major depressive disorder. Low serotonin impairs mood regulation, while HPA hyperactivity elevates stress hormones, exacerbating symptoms.

Flashcard 50: Which brain region is critical for forming new declarative memories and is stress-sensitive via cortisol?

Answer: Hippocampus. Chronic cortisol exposure can cause hippocampal atrophy.

Flashcard 51: Which finding supports a genetic contribution: higher concordance in MZ than DZ twins?

Answer: Genetic factors contribute to the disorder. MZ twins share more genes, so higher concordance suggests genetic influence.

Flashcard 52: What is the primary mechanism of serotonin-norepinephrine reuptake inhibitors (SNRIs)?

Answer: Inhibit reuptake of serotonin and norepinephrine (block SERT and NET). Dual inhibition elevates both neurotransmitters in synapses, effective for depression resistant to SSRIs.

Flashcard 53: Which neurotransmitter is the primary inhibitory transmitter and is targeted by benzodiazepines?

Answer: GABA. Reduces neural excitability; enhanced by anti-anxiety drugs.

Flashcard 54: Which dopamine pathway hypoactivity is most associated with negative symptoms of schizophrenia?

Answer: Mesocortical pathway. Underactivity in this prefrontal pathway contributes to cognitive deficits and emotional blunting in schizophrenia.

Flashcard 55: Which neurotransmitter is most strongly linked to depression in the monoamine hypothesis?

Answer: Decreased serotonin (often with decreased norepinephrine). Monoamine hypothesis: low 5-HT (and NE) causes depressive symptoms.

Flashcard 56: Which neurotransmitter is most directly associated with anxiolysis via increased inhibition?

Answer: GABA. Primary inhibitory neurotransmitter; benzodiazepines enhance GABA.

Flashcard 57: What is the key limitation of heritability estimates for individuals?

Answer: They do not predict an individual's risk; they apply to populations. Heritability describes population variance, not individual genetic risk.

Flashcard 58: What neurotransmitter deficit is classically associated with Parkinson disease?

Answer: Decreased dopamine in the nigrostriatal pathway. Loss of DA neurons causes motor symptoms (tremor, rigidity).

Flashcard 59: What is the primary mechanism of benzodiazepines for acute anxiety?

Answer: Increase GABA$_A$ receptor activity (positive allosteric modulators). Enhance GABA's inhibitory effects at receptors.

Flashcard 60: Which neurotransmitter abnormality is classically linked to OCD in MCAT frameworks?

Answer: Serotonin dysregulation (often conceptualized as decreased 5-HT). SSRIs treat OCD by increasing serotonin availability.

Flashcard 61: Which dopamine pathway hyperactivity is most associated with positive symptoms of schizophrenia?

Answer: Mesolimbic pathway. Overactivity in this reward-related pathway underlies positive symptoms like paranoia and auditory hallucinations.

Flashcard 62: What neurotransmitter deficit is classically associated with Alzheimer disease?

Answer: Decreased acetylcholine (cholinergic deficit). ACh-producing neurons degenerate, especially in the basal forebrain.

Flashcard 63: Identify the HPA-axis hormone that is commonly elevated with chronic stress.

Answer: Cortisol. Primary stress hormone released by adrenal cortex.

Flashcard 64: What is the HPA axis response pattern commonly associated with chronic stress and depression?

Answer: Hyperactive HPA axis with elevated cortisol. Chronic stress dysregulates hypothalamic-pituitary-adrenal feedback.

Flashcard 65: What is the primary mechanism of SNRIs in depression treatment?

Answer: Inhibit serotonin and norepinephrine reuptake. Dual action blocks both SERT and NET transporters.

Flashcard 66: Which neurotransmitter is classically increased at the synapse by SSRIs to treat depression and anxiety?

Answer: Serotonin ($5$-HT). SSRIs block reuptake, increasing synaptic serotonin levels.

Flashcard 67: What is the diathesis–stress model of psychological disorders?

Answer: Disorder risk = predisposition (diathesis) + environmental stressors. Combines genetic vulnerability with life stress to explain disorder onset.

Flashcard 68: What is the core biological feature that distinguishes delirium from dementia?

Answer: Delirium is acute and fluctuating; dementia is chronic and progressive. Delirium develops rapidly with attention deficits; dementia develops slowly with memory loss.

Flashcard 69: Which brain region is commonly hyperactive in anxiety disorders and fear conditioning?

Answer: Amygdala. Processes emotional threats, with hyperactivity leading to exaggerated fear responses in anxiety.

Flashcard 70: What is epigenetics as it relates to psychological disorders?

Answer: Environmental effects on gene expression without changing DNA sequence. Modifies gene activity via methylation/histones, not mutations.

Flashcard 71: Which brain region supports executive control and is often hypoactive in ADHD?

Answer: Prefrontal cortex. Regulates attention, planning, and impulse control.

Flashcard 72: Which disorder is most associated with reduced hippocampal volume after chronic stress exposure?

Answer: Posttraumatic stress disorder (PTSD). Chronic stress in PTSD atrophies the hippocampus, impairing memory consolidation and fear extinction.

Flashcard 73: What is epigenetics in the context of psychological disorders?

Answer: Environment-driven changes in gene expression without DNA sequence change. Stress/trauma can alter gene activity via methylation/histones.

Flashcard 74: Which study design best separates genetic effects from shared environment by studying adoptees?

Answer: Adoption study (biological vs adoptive relatives). Compares adoptee traits to biological vs adoptive parents.

Flashcard 75: What is the primary mechanism of SSRIs in depression treatment?

Answer: Inhibit serotonin reuptake, increasing synaptic 5-HT. Blocks SERT transporter, keeping serotonin in synapse longer.

Flashcard 76: Which study design most directly estimates genetic influence by comparing MZ vs DZ twins?

Answer: Twin study (MZ vs DZ concordance comparison). MZ twins share 100% genes; DZ share 50%, revealing genetic effects.

Flashcard 77: Which brain region classically shows reduced volume in major depressive disorder?

Answer: Hippocampus. Stress and depression cause hippocampal atrophy.

Flashcard 78: What does heritability mean in behavioral genetics?

Answer: Proportion of trait variance in a population due to genetic variation. It quantifies the genetic contribution to phenotypic differences, estimated via twin and adoption studies.

Flashcard 79: Identify the hormone released from the adrenal cortex as the end-product of HPA axis activation.

Answer: Cortisol. Primary stress hormone; chronically elevated in depression.

Flashcard 80: Which brain region is most associated with executive control and impulse regulation?

Answer: Prefrontal cortex. Top-down control center for planning and inhibiting behaviors.

Flashcard 81: What is the core pharmacologic action of typical antipsychotics?

Answer: D$2$ receptor antagonism (dopamine blockade). Blocks dopamine receptors to reduce positive symptoms.

Flashcard 82: Which option best reflects gene–environment interaction (G$\times$E) in psychopathology?

Answer: Genetic risk alters sensitivity to environmental stressors. Genes modify how individuals respond to environmental factors.

Flashcard 83: Which neurotransmitter is most associated with inhibitory signaling and anxiety reduction (target of benzodiazepines)?

Answer: GABA. Primary inhibitory NT; benzos enhance its calming effects.

Flashcard 84: What is meant by heritability in behavioral genetics?

Answer: Proportion of trait variance in a population due to genetic differences. Measures genetic contribution to population variation, not individual traits.

Flashcard 85: Which brain region is most associated with fear conditioning and is hyperactive in many anxiety disorders?

Answer: Amygdala. Processes threat detection and emotional salience.

Flashcard 86: Which brain structure shows reduced volume most classically associated with PTSD and chronic stress exposure?

Answer: Hippocampus. Stress hormones damage hippocampal neurons over time.

Flashcard 87: Which brain region supports executive control and is often hypoactive in depression and ADHD?

Answer: Prefrontal cortex. Reduced activity impairs planning, focus, and emotional regulation.

Flashcard 88: Which neurotransmitter is most associated with excitatory signaling and NMDA receptor hypotheses in schizophrenia?

Answer: Glutamate. Primary excitatory NT; hypofunction may contribute to psychosis.

Flashcard 89: What does heritability estimate in behavioral genetics represent?

Answer: Proportion of trait variance in a population due to genetic variation. Measures how much genes (vs environment) contribute to individual differences.

Flashcard 90: Which endocrine axis is commonly dysregulated in major depressive disorder and chronic stress?

Answer: HPA axis (hypothalamic-pituitary-adrenal axis). Overactive in depression, causing elevated cortisol levels.

Flashcard 91: Which dopamine pathway is most linked to positive symptoms of schizophrenia?

Answer: Mesolimbic pathway hyperactivity. Overactive reward pathway causes hallucinations and delusions.

Flashcard 92: Which brain region is most associated with fear conditioning and threat detection?

Answer: Amygdala. Processes emotional salience and triggers fear responses.

Flashcard 93: What is the core neurobiological mechanism of SSRIs?

Answer: Inhibit serotonin reuptake, increasing synaptic 5-HT. Blocks SERT transporter, prolonging serotonin's synaptic action.

Flashcard 94: What is the key limitation of twin studies that can inflate genetic estimates?

Answer: Equal environments assumption may be violated. MZ twins may be treated more similarly than DZ twins.

Flashcard 95: What is the core neurobiological mechanism of lithium in bipolar disorder (high-level description)?

Answer: Mood stabilizer that modulates intracellular signaling (e.g., second messengers). Affects multiple pathways including GSK-3 and inositol systems.

Flashcard 96: What is the primary mechanism of monoamine oxidase inhibitors (MAOIs)?

Answer: Inhibit monoamine oxidase, decreasing breakdown of 5-HT, NE, and DA. Prevents enzymatic degradation of monoamines, increasing their availability for mood regulation.

Flashcard 97: What neurotransmitter abnormality is most associated with schizophrenia?

Answer: Increased dopamine signaling (especially mesolimbic pathway). Dopamine hypothesis: excess DA activity causes psychotic symptoms.

Flashcard 98: Which neurotransmitter system is classically implicated in anxiety disorders?

Answer: GABA (reduced inhibitory signaling is associated with anxiety). Primary inhibitory neurotransmitter; deficiency increases anxiety.

Flashcard 99: What is concordance in the context of twin studies of psychological disorders?

Answer: Probability both twins show the same trait or disorder. If one twin has disorder, concordance = chance the other does too.

Flashcard 100: Which neurotransmitter is classically reduced in depression and is targeted by SNRIs and TCAs?

Answer: Norepinephrine. Low NE linked to mood/energy; SNRIs block its reuptake.