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Question 1
Correct
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Which of the following is associated with dynamic mutations?
Your Answer: Fragile X
Explanation:Trinucleotide Repeat Disorders: Understanding the Genetic Basis
Trinucleotide repeat disorders are genetic conditions that arise due to the abnormal presence of an expanded sequence of trinucleotide repeats. These disorders are characterized by the phenomenon of anticipation, which refers to the amplification of the number of repeats over successive generations. This leads to an earlier onset and often a more severe form of the disease.
The table below lists the trinucleotide repeat disorders and the specific repeat sequences involved in each condition:
Condition Repeat Sequence Involved
Fragile X Syndrome CGG
Myotonic Dystrophy CTG
Huntington’s Disease CAG
Friedreich’s Ataxia GAA
Spinocerebellar Ataxia CAGThe mutations responsible for trinucleotide repeat disorders are referred to as ‘dynamic’ mutations. This is because the number of repeats can change over time, leading to a range of clinical presentations. Understanding the genetic basis of these disorders is crucial for accurate diagnosis, genetic counseling, and the development of effective treatments.
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This question is part of the following fields:
- Genetics
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Question 2
Correct
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Which of the following examples best illustrates a drug interaction that affects the way a drug is absorbed, distributed, metabolized, of eliminated in the body?
Your Answer: Change in gastrointestinal tract motility
Explanation:Drug Interactions: Understanding the Different Types
Drug interactions can occur in different ways, and it is important to understand the different types to avoid potential harm. Pharmacokinetic drug interactions happen when one drug affects the metabolism, absorption, of excretion of another drug. This can be due to enzyme induction of inhibition, changes in gastrointestinal tract motility and pH, chelation, competition for renal tubular transport, of changes in protein binding. On the other hand, pharmacodynamic drug interactions occur when one drug directly alters the effect of another drug. This can happen through synergism, antagonism, of interaction at receptors, such as allosteric modulation. It is important to note that pharmacodynamic drug interactions do not involve any absorption, distribution, metabolism, of excretion processes directly. By understanding the different types of drug interactions, healthcare professionals can better manage patients’ medications and prevent potential adverse effects.
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This question is part of the following fields:
- Psychopharmacology
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Question 3
Correct
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Which pathway's dopamine blockade is responsible for the antipsychotic-induced extrapyramidal side effects?
Your Answer: Nigrostriatal
Explanation:Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.
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This question is part of the following fields:
- Neurosciences
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Question 4
Correct
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What is the most consistently observed pathology in schizophrenia?
Your Answer: Reduced total grey matter volume
Explanation:Alzheimer’s disease is associated with the presence of Hirano bodies.
Schizophrenia is a pathology that is characterized by a number of structural and functional brain alterations. Structural alterations include enlargement of the ventricles, reductions in total brain and gray matter volume, and regional reductions in the amygdala, parahippocampal gyrus, and temporal lobes. Antipsychotic treatment may be associated with gray matter loss over time, and even drug-naïve patients show volume reductions. Cerebral asymmetry is also reduced in affected individuals and healthy relatives. Functional alterations include diminished activation of frontal regions during cognitive tasks and increased activation of temporal regions during hallucinations. These findings suggest that schizophrenia is associated with both macroscopic and functional changes in the brain.
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This question is part of the following fields:
- Neurosciences
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Question 5
Correct
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What is the most efficient screening tool for identifying harmful alcohol consumption and alcohol addiction?
Your Answer: AUDIT questionnaire
Explanation:Alcohol screening tools are available to assist in the diagnosis of alcohol problems. One such tool is the AUDIT (Alcohol Use Disorders Identification Test), which consists of 10 questions and covers harmful use, hazardous use, and dependence. Another tool is the FAST (Fast Alcohol Screening Test), which has just 4 questions and was developed for use in a busy medical setting. The CAGE is a well-known 4 question screening tool, but recent research has questioned its value. Other tools include SASQ (Single alcohol screening questionnaire), PAT (Paddington Alcohol Test), MAST (Michigan Alcoholism Screening Test), and RAPS4 (Rapid Alcohol Problem Screen 4). These tools can help identify hazardous of harmful alcohol consumption and alcohol dependence.
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This question is part of the following fields:
- Classification And Assessment
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Question 6
Correct
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What antihistamine medication is prescribed to treat extrapyramidal side effects?
Your Answer: Diphenhydramine
Explanation:Diphenhydramine is a type of antihistamine that belongs to the first generation. It is commonly used to alleviate extrapyramidal side effects (EPSE). Unlike second generation antihistamines, first generation antihistamines have anticholinergic properties and can penetrate the blood-brain barrier, resulting in sedative effects. The anticholinergic effects of first generation antihistamines are beneficial for treating EPSE, which is believed to be caused by excessive acetylcholine due to reduced dopamine activity. Dopamine normally inhibits acetylcholine, but when dopamine activity is reduced, acetylcholine levels increase, leading to EPSE.
Extrapyramidal side-effects (EPSE’s) are a group of side effects that affect voluntary motor control, commonly seen in patients taking antipsychotic drugs. EPSE’s include dystonias, parkinsonism, akathisia, and tardive dyskinesia. They can be frightening and uncomfortable, leading to problems with non-compliance and can even be life-threatening in the case of laryngeal dystonia. EPSE’s are thought to be due to antagonism of dopaminergic D2 receptors in the basal ganglia. Symptoms generally occur within the first few days of treatment, with dystonias appearing quickly, within a few hours of administration of the first dose. Newer antipsychotics tend to produce less EPSE’s, with clozapine carrying the lowest risk and haloperidol carrying the highest risk. Akathisia is the most resistant EPSE to treat. EPSE’s can also occur when antipsychotics are discontinued (withdrawal dystonia).
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This question is part of the following fields:
- Psychopharmacology
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Question 7
Correct
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Which base pairs are found within DNA?
Your Answer: Guanine and cytosine
Explanation:Genomics: Understanding DNA, RNA, Transcription, and Translation
Deoxyribonucleic acid (DNA) is a molecule composed of two chains that coil around each other to form a double helix. DNA is organised into chromosomes, and each chromosome is made up of DNA coiled around proteins called histones. RNA, on the other hand, is made from a long chain of nucleotide units and is usually single-stranded. RNA is transcribed from DNA by enzymes called RNA polymerases and is central to protein synthesis.
Transcription is the synthesis of RNA from a DNA template, and it consists of three main steps: initiation, elongation, and termination. RNA polymerase binds at a sequence of DNA called the promoter, and the transcriptome is the collection of RNA molecules that results from transcription. Translation, on the other hand, refers to the synthesis of polypeptides (proteins) from mRNA. Translation takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein.
The process of translation involves messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Transfer RNAs, of tRNAs, connect mRNA codons to the amino acids they encode, while ribosomes are the structures where polypeptides (proteins) are built. Like transcription, translation also consists of three stages: initiation, elongation, and termination. In initiation, the ribosome assembles around the mRNA to be read and the first tRNA carrying the amino acid methionine. In elongation, the amino acid chain gets longer, and in termination, the finished polypeptide chain is released.
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This question is part of the following fields:
- Genetics
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Question 8
Correct
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How can the four principles of medical ethics be stated?
Your Answer: Autonomy, Beneficence, Non-maleficence and Justice
Explanation:Ethical theory and principles are important in medical ethics. There are three key ethical theories that have dominated medical ethics: utilitarianism, deontological, and virtue-based. Utilitarianism is based on the greatest good for the greatest number and is a consequentialist theory. Deontological ethics emphasize moral duties and rules, rather than consequences. Virtue ethics is based on the ethical characteristics of a person and is associated with the concept of a good, happy, flourishing life.
More recent frameworks have attempted to reconcile different theories and values. The ‘four principles’ of ‘principlism’ approach, developed in the United States, is based on four common, basic prima facie moral commitments: autonomy, beneficence, non-maleficence, and justice. Autonomy refers to a patient’s right to make their own decisions, beneficence refers to the expectation that a doctor will act in a way that will be helpful to the patient, non-maleficence refers to the fact that doctors should avoid harming their patients, and justice refers to the expectation that all people should be treated fairly and equally.
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This question is part of the following fields:
- Social Psychology
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Question 9
Correct
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A 32-year-old man with a history of partial seizures is prescribed a second anticonvulsant due to inadequate control with his current medication. However, he experiences concentric visual field loss as a side effect. Which anticonvulsant is most likely responsible for this adverse reaction?
Your Answer: Vigabatrin
Explanation:Vigabatrin is known to cause visual field constriction in approximately 30% of its users. Although the majority of cases are asymptomatic, as the drug primarily affects peripheral fields and not central visual acuity, the effects are typically irreversible of only partially reversible after discontinuation of the medication. Patients who are over the age of 10 and are prescribed vigabatrin should undergo baseline threshold visual field testing and follow-up every six months. It is important for patients to report any new vision problems, such as blurring, double vision, of signs of peripheral vision impairment. Vigabatrin is only recommended for specialist use and is indicated for epilepsy that is not adequately controlled by other medications.
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This question is part of the following fields:
- Psychopharmacology
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Question 10
Correct
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What is the purpose of using confrontation during a clinical examination?
Your Answer: Visual field loss
Explanation:Confrontation Test
The confrontation test is a method used to assess a patient’s visual fields. This test involves comparing the patient’s visual field with that of the examiner. To perform the test, both the patient and the examiner cover one eye, and the examiner then brings their fingers into view from a peripheral position. By comparing the patient’s response to the examiner’s, the examiner can determine any visual field defects that may be present. The confrontation test is a simple and effective way to assess a patient’s visual fields and can be performed quickly and easily in a clinical setting.
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This question is part of the following fields:
- Classification And Assessment
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Question 11
Correct
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A 70-year-old patient is admitted to a medical ward with fulminant hepatic failure. The admitting team observe the patient displaying a tremor, sunflower cataracts, difficulty speaking, and personality change. What is the most probable diagnosis?
Your Answer: Wilson's disease
Explanation:Understanding Wilson’s Disease: Causes, Symptoms, and Management
Wilson’s disease, also known as hepatolenticular degeneration, is a genetic disorder that affects copper storage in the body. This condition is caused by a defect in the ATP7B gene, which leads to the accumulation of copper in the liver and brain. The onset of symptoms usually occurs between the ages of 10 and 25, with liver disease being the most common presentation in children and neurological symptoms in young adults.
The excessive deposition of copper in the tissues can cause a range of symptoms, including hepatitis, cirrhosis, basal ganglia degeneration, speech and behavioral problems, asterixis, chorea, dementia, Kayser-Fleischer rings, sunflower cataract, renal tubular acidosis, haemolysis, and blue nails. Diagnosis is based on reduced serum ceruloplasmin, reduced serum copper, and increased 24-hour urinary copper excretion.
The traditional first-line treatment for Wilson’s disease is penicillamine, which chelates copper. Trientine hydrochloride is an alternative chelating agent that may become first-line treatment in the future. Tetrathiomolybdate is a newer agent that is currently under investigation.
In summary, Wilson’s disease is a genetic disorder that affects copper storage in the body, leading to a range of symptoms that can affect the liver, brain, and eyes. Early diagnosis and treatment are essential to prevent complications and improve outcomes.
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This question is part of the following fields:
- Classification And Assessment
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Question 12
Correct
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What is a true statement about drugs utilized for treating dementia?
Your Answer: Rivastigmine inhibits butyrylcholinesterase
Explanation:Rivastigmine has the ability to inhibit both AChE and butyrylcholinesterase, while Donepezil is specifically a reversible inhibitor of AChE.
Pharmacological management of dementia involves the use of acetylcholinesterase inhibitors (AChE inhibitors) and memantine. AChE inhibitors prevent the breakdown of acetylcholine, which is deficient in Alzheimer’s due to the loss of cholinergic neurons. Donepezil, galantamine, and rivastigmine are commonly used AChE inhibitors in the management of Alzheimer’s. However, gastrointestinal side effects such as nausea and vomiting are common with these drugs.
Memantine, on the other hand, is an NMDA receptor antagonist that blocks the effects of pathologically elevated levels of glutamate that may lead to neuronal dysfunction. It has a half-life of 60-100 hours and is primarily renally eliminated. Common adverse effects of memantine include somnolence, dizziness, hypertension, dyspnea, constipation, headache, and elevated liver function tests.
Overall, pharmacological management of dementia aims to improve cognitive function and slow down the progression of the disease. However, it is important to note that these drugs do not cure dementia and may only provide temporary relief of symptoms.
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This question is part of the following fields:
- Psychopharmacology
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Question 13
Correct
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What defense mechanism is being demonstrated by a woman who is usually introverted and avoids social situations, but now insists on going out with friends every weekend, drinking excessively, and participating in karaoke?
Your Answer: Reaction formation
Explanation:In this situation, it is more appropriate to use the defense mechanism of reaction formation instead of sublimation. Sublimation involves redirecting an impulse into a positive outlet, but since the individual in question has a negative behavior of heavy drinking, it would not be effective. On the other hand, reaction formation involves expressing the opposite of the true impulse, which would be more suitable. It is important to note that sublimation and reaction formation do have some similarities, with sublimation being a more advanced version of reaction formation.
Intermediate Mechanism: Rationalisation
Rationalisation is a defense mechanism commonly used by individuals to create false but credible justifications for their behavior of actions. It involves the use of logical reasoning to explain away of justify unacceptable behavior of feelings. The individual may not be aware that they are using this mechanism, and it can be difficult to identify in oneself.
Rationalisation is considered an intermediate mechanism, as it is common in healthy individuals from ages three to ninety, as well as in neurotic disorders and in mastering acute adult stress. It can be dramatically changed by conventional psychotherapeutic interpretation.
Examples of rationalisation include a student who fails an exam and blames the teacher for not teaching the material well enough, of a person who cheats on their partner and justifies it by saying their partner was neglectful of unaffectionate. It allows the individual to avoid taking responsibility for their actions and to maintain a positive self-image.
Overall, rationalisation can be a useful defense mechanism in certain situations, but it can also be harmful if it leads to a lack of accountability and an inability to learn from mistakes.
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This question is part of the following fields:
- Classification And Assessment
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Question 14
Correct
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Which cognitive function is thought to be essential for the ventromedial prefrontal cortex?
Your Answer: Moral judgement
Explanation:The Neuroscience of Morality
Morality is a process that involves both instinctive feelings and rational judgement. The ventromedial prefrontal cortex (PFC) is responsible for the emotional baseline, while the dorsolateral PFC is involved in cognitive control and problem solving. Studies have shown that the ventromedial PFC is activated during the solving of moral problems, particularly when responding to emotionally charged scenarios. On the other hand, the dorsolateral PFC is involved in tamping down our innate, reactionary moral system. These findings suggest that morality is a dual process event that involves both emotional and cognitive systems in the brain.
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This question is part of the following fields:
- Neurosciences
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Question 15
Correct
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A 60-year-old woman presents with cognitive impairment, perseveration, and disinhibition. What neurological signs are likely to be observed during her examination?
Your Answer: Palmomental reflex
Explanation:Frontal lobe pathology can result in the elicitation of frontal release signs, such as palmomental reflexes. Ataxia may be present in conditions like normal pressure hydrocephalus, while cogwheel rigidity is commonly found in extrapyramidal syndromes. Contralateral hemisphere dysfunction can lead to postural arm drift. These signs occur when the frontal lobe’s normal inhibition of these responses is released. For more information, see Kipps and Hodges’ article Cognitive assessment for clinicians.
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This question is part of the following fields:
- Advanced Psychological Processes And Treatments
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Question 16
Correct
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Which one of these options is not a principle of Gestalt psychology?
Your Answer: Approximation
Explanation:Gestalt Psychology and the Laws of Perceptual Organization
Gestalt psychology emerged as a response to structuralism, which aimed to break down thoughts into their basic components. Instead, Gestalt psychologists recognized that individual items must be examined together, as they interact and add complexity to the overall picture. Max Wertheimer, Kurt Koffka, and Wolfgang Köhler are important names associated with Gestalt psychology. Wertheimer discovered the phi phenomenon, which explains how rapid sequences of perceptual events create the illusion of motion. The Gestalt laws of perceptual organization explain how we tend to organize parts into wholes. These laws include symmetry and order, similarity, proximity, continuity, closure, and common fate. These laws help us understand how the mind groups similar elements into collective entities of totalities, and how spatial or temporal grouping of elements may induce the mind to perceive a collective of totality. Additionally, the laws explain how points that are connected by straight of curving lines are seen in a way that follows the smoothest path, and how things are grouped together if they seem to complete a picture. Finally, elements with the same moving direction are perceived as a collective of unit.
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This question is part of the following fields:
- Social Psychology
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Question 17
Correct
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A child psychologist is conducting an evaluation of a new client who seems to be suppressing of denying some past traumatic events. The psychologist wants to administer a projective personality assessment to the child.
What would be the most appropriate assessment to use in this situation?Your Answer: Holtzman inkblot technique (HIT)
Explanation:Personality assessment can be approached in two ways: objective and projective. Objective assessment involves structured, standardized measurement tools that typically require self-reporting. This approach uses direct questions to gather information about a person’s opinion of themselves. In contrast, projective assessment involves unstructured and often ambiguous stimuli to elicit responses that reveal information about a person’s personality. The Holtzman inkblot technique (HIT) is an example of a projective measure, while the Eysenck personality questionnaire (EPQ), Personality Assessment Inventory (PAI), and Millon Clinical Multiaxial Inventory (MCMI) are all examples of objective measures. The EPQ, PAI, and MCMI all use a true of false self-reporting format to gather information about a person’s personality.
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This question is part of the following fields:
- Description And Measurement
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Question 18
Correct
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A 45-year-old woman has been diagnosed with schizophrenia. What factor indicates a negative outcome?
Your Answer: Gradual onset
Explanation:A slow and steady development indicates a negative outcome, while all other factors suggest a positive prognosis.
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This question is part of the following fields:
- Aetiology
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Question 19
Correct
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In your clinic, a 25-year-old female patient presents with a frequent history of wrist cutting. Upon evaluation, you determine that she has a personality disorder. What specific type of personality disorder is the most probable diagnosis?
Your Answer: Borderline personality disorder
Explanation:Anankastic personality disorder is a personality disorder characterized by a preoccupation with orderliness, perfectionism, and control. It falls under cluster C personality disorders according to DSM-IV classification.
Deliberate self-harm is commonly associated with cluster B personality disorders. In the United Kingdom, poisoning by drugs accounts for 90% of deliberate self-harm cases, while wrist cutting accounts for 6-7%, and all other methods combined account for 3-4%. Frequent wrist cutting can be a part of recurrent suicidal gestures seen in individuals with depressive disorder, schizophrenia, and borderline personality disorder.
The reasons for wrist cutting are varied and complex, including a means of punishment oneself, reducing tension, feeling bodily instead of emotional pain, wishing to die, testing the benevolence of fate, seeking an interruption to an unendurable state of tension, crying for help, communicating with others, and unbearable symptoms.
Borderline personality disorder (BPD) is characterized by impulsive acts, mood instability, and chaotic relationships. Individuals with BPD are impulsive in areas that have a potential for self-harm and exhibit recurrent suicidal gestures such as wrist cutting, overdose, of self-mutilation.
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This question is part of the following fields:
- Diagnosis
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Question 20
Correct
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Which of the following is not a known trigger for migraines?
Your Answer: Spicy foods
Explanation:Migraine
Migraine is a common condition that affects 5-10% of the population, with a higher prevalence in women than men (2-3:1). It typically starts in childhood of adolescence and has a strong familial association, with 2/3 of cases reporting a family history of migraine.
The most prominent symptom of migraine is headache, which is usually unilateral but can occur on both sides. Other symptoms include anorexia, nausea and vomiting, photophobia, and intolerance of noise.
In about 1/3 of cases, migraines are preceded by a visual aura (known as classic migraine). The most common form of visual aura is the ‘fortification spectra’ (semicircle of zigzag lights), but other disturbances such as micropsia, macropsia, zoom vision, mosaic vision, scotomas, and even hallucinations can occur.
Basilar migraines are a subtype of migraine where headache and aura are accompanied by difficulty speaking, vertigo, ringing in ears, of other brainstem-related symptoms, but not motor weakness.
Migraine can be triggered by various factors, including alcohol, cheese, chocolate, skipping meals, missing sleep, and oral contraceptives. Stress is also a common precipitant of migraine.
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This question is part of the following fields:
- Classification And Assessment
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Question 21
Correct
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A 12 year old male is referred by his GP following concerns by his school regarding his academic ability. He is unable to read of write. Which of the following would be the most appropriate measure of his intellectual functioning?
Your Answer: WISC
Explanation:The Wechsler Adult Intelligence Scale (WAIS) is a widely used intelligence test in clinical settings, designed for individuals aged 16 to 90. Its counterpart for children is the Wechsler Intelligence Scale for Children (WISC). The current version of WAIS, WAIS-IV, consists of four index scores, each comprising several subsets. These are the Verbal Comprehension Index, Perceptual Reasoning Index, Working Memory Index, and Processing Speed Index. The results are presented as two scores: Full Scale IQ and General Ability Index. The average score is 100, with a standard deviation of 15. However, the test becomes less accurate at the extremes of IQ (70-130). About 3% of people score below 70, which is the general cut-off for a significant learning disability.
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This question is part of the following fields:
- Classification And Assessment
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Question 22
Correct
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Freud believed that the conscience is located in which of the following?
Your Answer: Superego
Explanation:Freud’s Structural Theory: Understanding the Three Areas of the Mind
According to Freud’s structural model, the human mind is divided into three distinct areas: the Id, the Ego, and the Superego. The Id is the part of the mind that contains instinctive drives and operates on the ‘pleasure principle’. It functions without a sense of time and is governed by ‘primary process thinking’. The Ego, on the other hand, attempts to modify the drives from the Id with external reality. It operates on the ‘reality principle’ and has conscious, preconscious, and unconscious aspects. It is also home to the defense mechanisms. Finally, the Superego acts as a critical agency, constantly observing a person’s behavior. Freud believed that it developed from the internalized values of a child’s main caregivers. The Superego contains the ‘ego ideal’, which represents ideal attitudes and behavior. It is often referred to as the conscience. Understanding these three areas of the mind is crucial to understanding Freud’s structural theory.
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This question is part of the following fields:
- Social Psychology
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Question 23
Correct
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A 35-year-old male reported experiencing the scent of lavender when he listens to music. What is the most probable explanation for this phenomenon?
Your Answer: Synaesthesia
Explanation:Hallucinations and Illusions
Hallucinations can take on different forms, including reflex hallucinations, auditory hallucinations, and functional hallucinations. Reflex hallucinations occur when a stimulus in one sensory modality produces a hallucination in another. For example, someone may smell oranges when they hear music. Auditory hallucinations, on the other hand, are the presence of auditory experiences in the absence of a true stimulus. Functional hallucinations occur when an external stimulus provokes a hallucination, and the normal perception of the external stimulus and the hallucinatory experience are in the same modality.
In addition to hallucinations, there are also illusions, which involve false perceptions with sensory distortions. Kinaesthetic hallucinations are a type of hallucination that involve bodily movements. Understanding the different types of hallucinations and illusions can help individuals better recognize and manage these experiences.
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This question is part of the following fields:
- Descriptive Psychopathology
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Question 24
Correct
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What is the primary mechanism by which valproate stabilizes mood?
Your Answer: GABA agonism
Explanation:Mechanisms of Action of Different Drugs
Understanding the mechanisms of action of different drugs is crucial for medical professionals. It is a common topic in exams and can earn easy marks if studied well. This article provides a list of drugs and their mechanisms of action in different categories such as antidepressants, anti dementia drugs, mood stabilizers, anxiolytic/hypnotic drugs, antipsychotics, drugs of abuse, and other drugs. For example, mirtazapine is a noradrenaline and serotonin specific antidepressant that works as a 5HT2 antagonist, 5HT3 antagonist, H1 antagonist, alpha 1 and alpha 2 antagonist, and moderate muscarinic antagonist. Similarly, donepezil is a reversible acetylcholinesterase inhibitor used as an anti dementia drug, while valproate is a GABA agonist and NMDA antagonist used as a mood stabilizer. The article also explains the mechanisms of action of drugs such as ketamine, phencyclidine, buprenorphine, naloxone, atomoxetine, varenicline, disulfiram, acamprosate, and sildenafil.
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This question is part of the following fields:
- Psychopharmacology
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Question 25
Correct
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What percentage of Caucasians have a deficiency in the cytochrome P450 enzyme 2D6?
Your Answer: 6%
Explanation:Debrisoquine hydroxylase is the primary enzyme responsible for metabolizing several antidepressants, such as tricyclics, selective serotonin reuptake inhibitors (SSRIs), venlafaxine, and others. Approximately 5 out of 100 individuals are poor metabolisers, which can lead to increased side effects from medications that rely on CYP2D6 for metabolism. Conversely, ultra-rapid metabolisers may require higher than average doses of these medications due to their highly active forms of the enzyme.
The Cytochrome P450 system is a group of enzymes that metabolize drugs by altering their functional groups. The system is located in the liver and small intestine and is involved in drug interactions through enzyme induction of inhibition. Notable inducers include smoking, alcohol, and St John’s Wort, while notable inhibitors include grapefruit juice and some SSRIs. CYP2D6 is important due to genetic polymorphism, and CYP3A4 is the most abundant subfamily and is commonly involved in interactions. Grapefruit juice inhibits both CYP1A2 and CYP3A4, while tobacco smoking induces CYP1A2. The table summarizes the main substrates, inhibitors, and inducers for each CYP enzyme.
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This question is part of the following fields:
- Psychopharmacology
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Question 26
Correct
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What is a true statement about ADHD?
Your Answer: The heritability is similar in males and females.
Explanation:ADHD and Genetics
Decades of research have shown that genetics play a crucial role in the development of attention deficit hyperactivity disorder (ADHD) and its comorbidity with other disorders. However, twin estimates of heritability being less than 100% suggest that environmental factors also play a role. Parents and siblings of a child with ADHD are more likely to have ADHD themselves, but the way ADHD is inherited is complex and not related to a single genetic fault. The heritability of ADHD is around 74%, and longitudinal studies show that two-thirds of ADHD youth will continue to have impairing symptoms of ADHD in adulthood. Adoption studies suggest that the familial factors of ADHD are attributable to genetic factors rather than shared environmental factors. The heritability is similar in males and females, and studies suggest that the diagnosis of ADHD is the extreme of a continuous distribution of ADHD symptoms in the population. Several candidate genes, including DAT1, DRD4, DRD5, 5 HTT, HTR1B, and SNAP25, have been identified as significantly associated with ADHD.
Source: Faraone (2019) Genetics of attention deficit hyperactivity disorder. Molecular Psychiatry volume 24, pages 562–575 (2019).
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This question is part of the following fields:
- Genetics
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Question 27
Correct
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What is a true statement about 'working memory'?
Your Answer: Its capacity increases with age during childhood
Explanation:Throughout childhood, there is an increase in working memory capacity. Additionally, research has demonstrated that working memory performance can be enhanced, particularly in individuals with ADHD.
Memory Forms
Memory is the ability to store, retain, and retrieve information. There are different forms of memory, including sensory memory, short-term/working memory, and long-term memory.
Sensory memory is the capacity for briefly retaining the large amounts of information that people encounter daily. It includes echoic memory (gathered through auditory stimuli), iconic memory (gathered through sight), and haptic memory (acquired through touch).
Short-term memory is the ability to keep a small amount of information available for a short period of time. Atkinson and Shiffrin’s multistore model (1968) suggests the existence of a short-term storehouse with limited capacity. Baddeley and Hitch (1974) further developed the concept of short-term memory, which eventually became known as Baddeley’s multi-storehouse model (2000). This model includes the central executive, visuospatial sketchpad, phonological buffer/loop, and episodic buffer.
Long-term memory includes declarative (of explicit) memories, which can be consciously retrieved, and nondeclarative (of implicit) memories, which cannot. Declarative memory includes episodic memory (stores personal experiences) and semantic memory (stores information about facts and concepts). Non-declarative memory includes procedural memory (recalls motor and executive skills), associative memory (storage and retrieval of information through association with other information), and non-associative memory (refers to newly learned behavior through repeated exposure to an isolated stimulus).
Overall, memory is a complex and essential cognitive function that plays a crucial role in learning, reasoning, and understanding.
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This question is part of the following fields:
- Social Psychology
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Question 28
Correct
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A 35-year-old female presents with secondary amenorrhea and is currently taking medication for bipolar disorder. What is the initial diagnostic test that should be performed?
Your Answer: Pregnancy test
Explanation:While antipsychotics can cause secondary amenorrhoea by increasing prolactin levels, it is important to first rule out pregnancy as it is the most common cause of this condition.
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This question is part of the following fields:
- Psychopharmacology
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Question 29
Correct
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Which of these options represents a primary reinforcer?
Your Answer: Food
Explanation:Operant Conditioning: Reinforcement, Punishment, and More
Operant conditioning, also known as instrumental learning, is a theory of learning developed by B.F. Skinner. It suggests that people learn by interacting with their environment. Reinforcement and punishment are key concepts in operant conditioning. A reinforcer is a stimulus of event that increases the likelihood of a behavior being repeated. Reinforcement can be positive of negative. Positive reinforcement occurs when a behavior is strengthened by adding a rewarding stimulus, while negative reinforcement occurs when a behavior is strengthened by removing an unpleasant stimulus. A punisher is a stimulus that decreases the likelihood of a behavior being repeated. Positive punishment occurs when a behavior is reduced in frequency by adding an unpleasant stimulus, while negative punishment occurs when a behavior is reduced in frequency by removing a pleasant stimulus.
Primary reinforcers are instinctual desires such as food, water, social approval, and sex. Secondary reinforcers, also known as conditioned reinforcers, are not innately appreciated and people have to learn to like them through classical conditioning of other methods. Secondary reinforcers include things such as money. Different patterns of reinforcement have different influences on the response. There are five main reinforcement schedules: fixed interval, variable interval, fixed ratio, variable ratio, and random. Variable ratio schedules are most resistant to extinction.
Shaping and chaining are techniques used when an exact behavior cannot be performed and so cannot be rewarded. Shaping involves rewarding successive, increasingly accurate approximations to the behavior, while chaining involves breaking a complex task into smaller, more manageable sections. Escape conditioning refers to a situation whereby an aversive situation is removed after a response. It is a form of negative reinforcement. Habituation refers to the phenomenon whereby there is a decrease in response to a stimulus over time. Covert sensitization is a technique used whereby someone learns to use mental imagery to associate a behavior with a negative consequence.
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Question 30
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A 62-year-old male with a prolonged history of alcohol abuse arrives at the Emergency department displaying evident disorientation, a lateral gaze palsy, and lack of coordination. His blood alcohol concentration measures at 68 mg per 100 mls blood, while his electrolytes, complete blood count, and liver function tests appear normal. What is the most probable diagnosis?
Your Answer: Wernicke's encephalopathy
Explanation:If a patient presents with confusion, eye signs (ophthalmoplegia of nystagmus), and an ataxic gait, Wernicke’s encephalopathy should be suspected. This serious, but reversible, condition is most commonly caused by alcohol dependence and is due to a lack of Vitamin B1 (thiamine). Acute alcohol intoxication is unlikely as the patient’s blood alcohol level is below the legal limit for driving. Amnesic syndrome is not the correct diagnosis as it is characterized by impairment of new learning without obvious confusion. Normal pressure hydrocephalus is characterized by urinary incontinence, gait disturbance, and cognitive decline. Subdural hematoma is not a likely diagnosis as there is no history of head injury.
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- Diagnosis
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