OTY 2003 Module Intro and Lecture 1 - Psychopathology, Diagnosis & Aetiology 2021 PDF

OTY 2003 Application of Social & Clinical Psychology in Occupational Therapy Module Lead: A/Prof Tan Bhing Leet Director of Programmes, Health and Social Sciences OTY2003 Module Learning Outcomes After successfully completing this module, you should be able to: 1. 2. 3. 4. 5. 6. Understand the diagn...

OTY 2003 Application of Social & Clinical Psychology in Occupational Therapy Module Lead: A/Prof Tan Bhing Leet Director of Programmes, Health and Social Sciences OTY2003 Module Learning Outcomes After successfully completing this module, you should be able to: 1. 2. 3. 4. 5. 6. Understand the diagnostic classification system of psychiatric disorders Differentiate prevalent mental disorders Choose appropriate assessment measures to facilitate diagnostic formulation Evaluate major therapeutic approaches for mental disorders Apply assessment, diagnostic and treatment skills on clinical cases Develop a comprehensive biopsychosocial assessment report of a clinical case, incorporating discipline-specific recommendations 7. Appraise theoretical models of recovery and psychiatric rehabilitation principles Mode of Learning ONLINE LECTURES. FACE-TO-FACE SEMINARS. WEEKLY READINGS CREDITS: 5 CREDITS Required Textbook: Revel: Hooley, J.M., Nock, M.K. and Butcher, J.N. (2020) Abnormal Psychology. 18th Edition, Pearson. Available in your xSITe LMS OTY 2003 module! Textbook: American English spelling. Lecture slides and SIT official English: British English spelling. Tests/exams: either is acceptable. Revel Abnormal Psychology Assignments will be given periodically within Revel. No weightage, but good to cultivate a habit of regular revision and completion of learning activities. Revel Quiz: KIV one before Mid-trimester Test and one before Final Test. Awareness of mental health conditions seen in clinical settings as an occupational therapist. Approach to Learning this Module Would we ‘medicalise’ mental illnesses, when we get to know more about their presenting symptoms and aetiology (causes)? You as your own therapist? Well-Thy Minds: a Student Led Initiative https://sitsingaporetechedumy.sharepoint.com/personal/1900414_sit_singa poretech_edu_sg/Documents/Attachments/abo ut%20us%20video%20(editted).mp4 https://youtu.be/diY4zruIsxQ Module Contents and Weekly Reading List Refer to OTY 2003 Module Profile. Weekly Reading List file. Assessment Task Continuous Assessment 1: Mid-trimester Test (MCQs) Assessments Test assesses applied, conceptual and factual knowledge (Weeks 1-6). Continuous Assessment 2: Case Presentation Students will develop and present a biopsychosocial assessment report of a clinical case to apply their diagnostic and treatment knowledge. Continuous Assessment 3: Final Test (MCQs and case study) Test assesses applied, conceptual and factual knowledge (Weeks 1-12). Tentative Weighting week/due date 35% Week 8 30% Week 11 35% Week 14 Mid-Trimester and Final Tests Mid-trimester Test Final Test Total marks: 70. Format: MCQ (Onsite xSITe Quiz) Total marks: 70 Format: MCQs 1 open-ended case study (10 marks) Onsite xSITe Quiz. Case Presentation Refer to ‘Case Presentation Instructions’ Case Presentation Grouping: Refer to ‘OTY2003 Case Presentation Student Groupings2021’ pdf file in xSITe LMS. Psychopathology Fundamentals, Diagnostic Classification & Aetiology A/Prof Tan Bhing Leet Dr Angela Papadimitriou Health & Social Sciences Cluster Learning Objectives Identify criteria for abnormal behaviour. Understand diagnostic classification approaches for psychiatric disorders (ICD and DSM). Distinguish between incidence & prevalence. Explain burden of disease. Distinguish between risk factors & causes. Understand the key aetiological paradigms for psychiatric disorders. Apply the Biopsychosocial Approach for psychiatric disorders. Definition of Psychopathology Psychopathology: scientific study of mental health disorders including: efforts to understand genetic, biological, psychological, and social causes (origin) effective classification schemes (nosology) course across all stages of development (development) manifestations of behaviours indicative of clinical treatment Psychopathology: psyche = soul pathos = suffering -ology = study of Psychopathology synonym for mental illness Mental Illness: wide range of mental health conditions (disorders) characterised by psychological dysfunction and abnormal behaviour. History of Psychopathology Asylums ‘Removing Shackles’ 17th -19th Century 16th Century Renaissance 14-18th Century Middle Ages 5th-4th Century BC 6th-3th Century BC Stone Age Mental Hospital Care in 20th Century Deinstitutionalization Movement Large numbers of mental hospital closures and shift to communitybased residences Global movement: Asia, Europe, U.S. Considered more humane and cost effective Some issues for patients and society. Abnormal Behaviour No universal agreement about what is abnormality or mental disorder Why is it so challenging to define abnormality? Mental illness is multifactorial. A single behaviour, like a single symptom, can not make someone abnormal. Culture (& society) plays a significant role in determining what is / is not abnormal. Abnormal Behaviour Indicators No single indicator sufficient in itself to determine abnormality. The more that someone has difficulties in these areas, the more likely the person has some form of psychiatric condition. 1. Personal (Subjective) Distress: emotional suffering has a significant impact on person’s functioning manic state, or lack of distress of serial killer Subjective distress is an element of abnormality but it is not a necessary condition to consider abnormal. Are all abnormal behaviours considered distressing? When and at what degree is discomfort abnormal? Abnormal Behaviour Indicators 2. Maladaptive Behaviour: inability to adapt to stressors and everyday demands of life impacting well-being. issue of subjectivity. 3. Statistical Deviance: rare/infrequent behaviour or thinking that deviates from the average or majority Are all rare behaviours (math genius) abnormal? Depression is becoming more common. Some mental disorders are extremely rare (e.g., gender dysphoria affects 1 person out of 30,000). Who determines what is maladaptive? How about high functioning depression? Abnormal Behaviour Indicators 4. Social Norm Deviance: deviance from social norms/cultures Are all socially different behaviours abnormal?  wrong dress code for significant social event. Does social discomfort make a behaviour abnormal?  violation of personal space Can irrationality and unpredictability define abnormality? Should symptoms be defined by social norms or culture?  hallucinations (symptom) or visions (faith)? Abnormal Behaviour Indicators 5. Dangerousness: danger to oneself or another person: Dangerousness is an exception and not a norm for people with mental illness (Corrigan & Watson, 2005). Crimes largely committed by persons without psychiatric disorders. Plea of sanity. Abnormality Key Points No one element is sufficient to define or determine abnormality. Definition of psychological disorder based on all criteria: atypical behaviour & thinking significantly distressing, harmful to oneself or others and disruptive to daily life functioning. Culture plays a role in determining what is/is not abnormal. Perception of abnormality fluctuates reflecting society’s constantly evolving views. Discussions 1. What are the ‘abnormal’ behaviours of the characters described in this film trailers/clips. 2. How is the character’s quality of life affected? 3. What sort of ‘ personal/cultural value judgement’ do you exercise when you identify these ‘abnormal’ behaviour/speech? Are these absolute standards? As Good as It Gets: https://www.youtube.com/watch?v=oAK0FmZbsu8 A Beautiful Mind: ‘She Never Gets Old’: Watch from 0:30 to 6:32 https://www.youtube.com/watch?v=A3vktOTaOAU Discussions Silver Linings Playbook (warning: some bad language): 0- 2:55 https://www.youtube.com/watch?v=JrsjI7DrOuQ The Hours: 0- 4:45 https://www.youtube.com/watch?v=S-U0ZomAkAM: Formal Classification of Psychiatric Disorders Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), American Psychiatric Association (2013). International Classification of Diseases, 11th Edition (ICD-11) World Health Organisation (2019). DSM standard guide in US, ICD in Europe & many other countries. Usage in Singapore:  ICD system used by Ministry of Health and hospital administrators for purpose of measuring and keeping track of diseases in the population and to calculate subsidies and reimbursements to public hospitals.  DSM used mainly in psychiatric settings, research and academia. DSM Facts DSM facts: 1st DSM (1952) 86 pages and 100 disorders. DSM-IV-TR (2000): 900 pages and about 365 disorders. DSM-5 (2013): 947 pages and over 400 disorders. DSM-I & DSM-II (1968) shaped by psychoanalytic tradition: diagnoses based on psychodynamic processes, not on observable behaviour. DSM-III (1980): influenced by biomedical tradition: inclusion of explicit diagnostic criteria ↑ reliability. DSM-III, IV & IV-TR based on categorical, multi-axial system: Axis I: Clinical Syndromes Axis II: Personality Disorders Axis III: Medical Conditions Axis IV: Psychosocial & Environmental Factors Axis V: Global Assessment Functioning (GAF) DSM 5 The DSM-5 (2013) replaced multiaxial (Axis I to V) & categorical classification of mental disorders of previous DSMs with a dimensional approach. Disorders viewed & ranked on a continuum vs present/absent. Dimensions: allows clinicians to rate disorders along a continuum of severity. Lists criteria for each specific category (inclusion & exclusion). More comprehensive with more subtypes of disorders. Allows for gender related differences in diagnosis. Culture and classification:  Incorporates influence of cultural factors in both expression and recognition of symptoms of mental disorders.  Includes glossary of cultural concepts of distress. Neurodevelopmental Disorders. Schizophrenia Spectrum & Other Psychotic Disorders. Bipolar & Related Disorders. Depressive Disorders. Anxiety Disorders. Obsessive-Compulsive & Related Disorders. Trauma & Stressor Related Disorders. Dissociative Disorders Somatic Symptom Disorders Feeding & Eating Disorders Elimination Disorders (eg: enuresis). Sleep-Wake Disorders (eg: narcolepsy). Sexual Dysfunctions Gender Dysphoria. Disruptive, Impulse Control & Conduct Disorders. Substance Use & Addictive Disorders. Neurocognitive Disorders (eg: dementia). Personality Disorders. Paraphilic Disorders (eg: Pedophilic disorder). ICD Facts Current ICD-11 (chapter 6) ICD-11-List of Psychiatric Disorders 1. 2. 3. 4. 5. 6. 7. 8. 9. : Anxiety or fear-related disorders. Catatonia. Disorders of bodily distress or bodily experience. Disorders due to substance use or addictive behaviors. Disorders specifically associated with stress. Disruptive behavior or dissocial disorders. Dissociative disorders. Elimination disorders. Factitious disorders. 10. Feeding or eating disorders. 11. Impulse control disorders. 12. Mental or behavioral disorders associated with pregnancy, childbirth and the puerperium. 13. Mood disorders. 14. Neurocognitive disorders. 15. Neurodevelopmental disorders. 16. Obsessive-compulsive or related disorders. 17. Paraphilic disorders. 18. Personality disorders and related traits. 19. Schizophrenia or other primary psychotic disorders. Geddes, J., Andreasen, N., Goodwin, G., Regier, D., Goldberg, D., Üstün, B., & Reed, G. (2020-03). DSM-5 and ICD-11 classifications. In New Oxford Textbook of Psychiatry. Oxford, UK: Oxford University Press. Retrieved 25 May. 2021, from https://oxfordmedicine.com /view/10.1093/med/978019 8713005.001.0001/med9780198713005-chapter-7. Table 7.1 Geddes, J., Andreasen, N., Goodwin, G., Regier, D., Goldberg, D., Üstün, B., & Reed, G. (2020-03). DSM-5 and ICD-11 classifications. In New Oxford Textbook of Psychiatry. Oxford, UK: Oxford University Press. Retrieved 25 May. 2021, from https://oxfordmedicine.com /view/10.1093/med/978019 8713005.001.0001/med9780198713005-chapter-7. Table 7.1 Frequency of Psychiatric Disorders Epidemiology: scientific study of frequency and distribution of diseases and disorders within a population. 2 terms particularly important in epidemiological research:  Incidence  Prevalence Incidence:  number of new cases of a disorder that appear in a population during a specific period of time. Frequency of Mental Disorders Prevalence: Number of active cases (old and new) present in a population during a specific period/time. Prevalence figures typically expressed in percentages. Several types of prevalence estimates. Point Prevalence 1-year Prevalence Lifetime Prevalence Proportion of active cases of a disorder in a given population at a given point in time. Proportion of active cases of a disorder in a given population throughout entire year. Proportion of people in given population affected by a disorder at some point during their lives. Subramaniam, M , et.al. (2019). Tracking the mental health of a nation: prevalence and correlates of mental disorders in the second Singapore mental health study. Epidemiology and psychiatric sciences, 29, e29. https://doi.org/10.1017/S2045796019000179 Burden of Mental Illness Across Lifespan Abnormal Psychology, 17th ed. 2017 Hooley etal Singapore Burden of Disease Singapore Burden of Disease Study(2010) Ministry ofHealth Burden of Mental Illnesses in Singapore Why do you think schizophrenia is the most burdensome? Singapore Burden of Disease Study(2010) Ministry ofHealth Aetiology (Causes) and Risk Factors Aetiology (Etiology): scientific investigation of factors or causes that are responsible for, or related to, the development of disorders. Risk Factors: factors that make individuals at risk or prone to the development of a disorder.  Identify vulnerable groups.  Develop preventative interventions. *Predisposing, Precipitating and Perpetuating Factors Predisposing factors Occur early in life and may have effects several years later. Eg: John’s loss of his parent at age 5 may predispose him to depression. Precipitating factors Occur shortly before onset of disorder. Eg: Barry (John’s best friend)’s migration to Canada precipitated John’s first onset of depression. Perpetuating factors Occur after onset of disorder and cause it to be maintained. Eg: John has been withdrawing himself and lying in bed the whole day, which leads to lack of meaningful engagement and perpetuates his depression. Zoom Poll: Predisposing, Precipitating and Perpetuating Factors Aetiology and Risk Factors of Psychiatric Conditions: The Biopsychosocial Approach Biological Perspective Biological Perspective Traditional biological stance: mental disorders as diseases. Categories of Biological factors relevant to abnormal behaviour. Genetic Vulnerabilities Brain dysfunction & Neural Plasticity Neurotransmitter & Hormonal Abnormalities in Brain & Central Nervous System (CNS) Genetic Vulnerabilities Abnormalities in structure or number of chromosomes associated with malfunctions & disorders (Down syndrome). Genes may not fully determine development of a mental disorder: they affect behavior indirectly. Vulnerability to psychiatric conditions almost always polygenic and influenced by:  abnormalities in some of the genes on chromosomes.  naturally occurring variations of genes (polymorphisms). Evidence for Neurodevelopmental Hypothesis (NDH) in Schizophrenia Genetic Factors Linkage and association studies identified 12 chromosomal regions containing 2181 known genes and 9 specific genes being involved in aetiology of schizophrenia. Many studies found downregulation in myelin and oligodendrocyterelated genes, which are important in formation and maintenance of myelin sheaths. (Fatemi & Folsom, 2009; Schizophrenia Working Group of the Psychiatric Genomics Consortium., 2014) Singapore Mental Health Conference Evolving Mental Healthcare to Meet Changing Needs Genetic Vulnerabilities Genotype: person’s genetic make-up (what you inherit). Phenotype: person’s observable characteristics resulting from interaction of genotype and environment (what is expressed). Genotype-Environment interaction Genetic factors are not necessary and sufficient to cause psychiatric conditions. Can contribute to vulnerability to develop psychopathology in presence of environmental stressor.  Eg: Phenylketonuria (PKU)-induced intellectual disability, due to build up of phenylalanine (amino acid). It can be prevented by altering diet from early age. Evidence for Neurodevelopmental Hypothesis (NDH) Genetic Factors Associations with genes involved in glutamatergic and dopamine neurotransmission. Interaction between genes and environment: genes related to hypoxia at childbirth are found to be associated with risk for schizophrenia. (Fatemi & Folsom, 2009; Schizophrenia Working Group of the Psychiatric Genomics Consortium., 2014) Singapore Mental Health Conference Evolving Mental Healthcare to Meet Changing Needs Genetic Vulnerabilities Behaviour Genetics (psychogenetics): study of influence of person’s genetic composition on its behaviour and interaction of heredity. 3 primary methods: Family history: observe samples of relatives of person & compare incidence in family vs rate in population. Twin method: compare rates of disorders in identical twins (monozygotic) vs rates in non-identical (dizygotic) twins. Genetic Vulnerabilities Adoption method: adopted children with normal biological parents vs children with biological parents with disorder. All 3 methods allow examination of environmental influences: Shared environmental influences: having both twins experiencing the same environment and family influences (eg: both children attending equally good schools). Nonshared environmental influences: having both twins experiencing different environment and family influences (e.g., each child attending a totally different type of school, bring one child up differently from another). Brain Dysfunction & Neural Plasticity Different psychiatric conditions associated with different neuroanatomical regions to various extents. Obsessive Compulsive Disorder (OCD): associated with dysregulation of the cortico-striato-thalamo-cortical (CSTC) circuit as well as at the basal ganglia (Ahmari et.al., 2013; Murphy, et.al., 2010). Schizophrenia: decreased grey matter volume (Filippi. Et.al., 2014). Stroke: person with stroke at the frontal region may present with personality changes (Low et.al., 2014). Brain Dysfunction & Neural Plasticity Developmental Systems Approach: Genetic Activity influences Environment Neural Activity influences Behaviour Neurotransmitter & Hormone Imbalances Neurotransmitter imbalance can result in abnormal behaviour Created in various ways: Overproduction: excessive production and/or release of neurotransmitter into synapse. Deactivation: dysfunction in deactivation of neurotransmitter Neurotransmitter in synapse. imbalances Abnormally Sensitive or Insensitive Receptors. 5 most studied neurotransmitters Norepinephrine (Noradrenaline). Dopamine. Serotonin. Glutamate. Gamma aminobutyric acid (GABA) Neurotransmitter & Hormone Imbalances Hormones produce psychophysiological responses. Hypothyroidism: ↓ thyroid function common cause of lethargy, depression, short-term memory loss. Mental health issues are common in thyroid disorders. Cortisol imbalance associated with depression and post-traumatic stress disorder (PTSD). Oestrogen, Progesterone and Testosterone: protect against loss of memory, cognition and progression of dementia. Postpartum depression: ↓ progesterone after childbirth causes low moods of postpartum depression. Menopause ↑ risk of mental health problems. In men, ↑oestrogen can cause depression or mood swings & ↓ testosterone can cause depression, fatigue, mental fogginess. Neurotransmitter & Hormone Imbalances Neurotransmitter Function Common Dysfunctions (Simplified) Dopamine (DA) Influences movement, learning, attention, sensations of pleasure. Oversupply: schizophrenia. Undersupply: Parkinson’s disease, depression. Serotonin (5-HT) Affects mood, appetite, sleep, anxiety. Undersupply: depression, sleep and eating disorders. Acetylcholine (ACh) Enables muscle action, learning and memory Oversupply: muscle contraction, convulsions. Undersupply: Alzheimer's disease. Norepinephrine Noradrenaline Helps control alertness and arousal. Oversupply: stress and panic disorder. Undersupply: depression. Gaba-amino butyric (GABA) Involved in sleep and inhibits movement Undersupply: seizures, tremors and insomnia. Endorphins Involved in pain relief Oversupply: insensitivity to pain. Undersupply: pain hypersensitivity, immune problems. Psychological Perspective Psychological Paradigms Psychodynamic CognitiveBehavioural Behavioural Psychodynamic Theory (Recap from HSC 1004) Freud theorised that a person’s behavior results from interaction of: Id (pleasure principle) Source of instinctual Drives. Ego (reality principle) Mediates between demands of Id and realities of external world. Superego (judicial branch) Outgrowth of internalising taboos and moral values of society. Mental disorder occurs when Id, Ego & Superego are in conflict, or one is overly dominant or underdeveloped. Superego Superego Id Overuse of immature/neurotic ego defense mechanisms: neurotism Superego Superego Id Failure/disintegration of ego defense or use of pathological mechanisms: psychosis Psychodynamic Theory (Recap from HSC 1004) Freud: mentally healthy individuals successfully pass 5 psychosexual stages during which Id, Ego & Superego are formed 1. Oral Stage (first 18months) 2. Anal Stage (18 – 36 months) 3. Phallic Stage (3 – 6 years) 4. Latency Stage (6 years – puberty) 5. Genital Stage (puberty on) Each stage produces certain amount of conflict & anxiety. If not resolved properly, normal development may be interrupted and child may be stuck (fixation) at that stage.  Oral stage: smoking?  Anal stage: stinginess? Early-stage conflicts distort personality. Poll: Ego Defense Mechanisms Psychodynamic Perspective (Recap from HSC 1004) Ego Defense Mechanisms: strategies used by ego to defend itself against anxiety Ego-Defense Mechanism Displacement. Discharging pent-up feelings, often of hostility, on objects less dangerous than those arousing the feelings. Fixation. Attaching oneself in an unreasonable or exaggerated way to some person, or arresting emotional development on a childhood or adolescent level. Projection. Attributing one’s unacceptable motives or characteristics to others. Rationalization. Using contrived explanations to conceal or disguise unworthy motives for one’s behavior. Reaction formation. Preventing the awareness or expression of unacceptable desires by an exaggerated adoption of seemingly opposite behavior. Regression. Retreating to an earlier developmental level involving less mature behavior and responsibility. Repression. Preventing painful or dangerous thoughts from entering consciousness. Sublimation. Channeling frustrated sexual/aggressive energy into substitutive activities. Behavioural Perspective Using concepts of: Classical Conditioning Operant Conditioning Observational Learning (Modelling) Maladaptive behavior is the result of learning that has gone awry. Example: Phobia of travelling in public transport and eventually public spaces.  Develops anxiety attack once in the MRT, leaves the place which reduces anxiety (operant conditioning). Generalises it to other modes of transportation (classical conditioning). Children acquire new fears by observing a parent behaving fearfully with some object or situation that the child did not initially fear (observational learning). Behavioural Perspective Behaviour therapy: focuses on changing specific behaviors and emotional responses, by eliminating undesirable reactions and learning desirable ones. Examples: Treating phobias by prolonged exposure to the feared object/situation. Derived from principles of extinction of classical conditioning. Teaching skills to persons with intellectual and developmental disabilities (IDD) using token economy, forward and backward chaining etc. These training methods use operant conditioning. The behavioral approach is well known for its specificity and measurable outcomes. Cognitive Behavioural Perspective Situation: At a party Thoughts People are avoiding me. Obviously, I’m not interesting to them. Emotions/ Feelings Sad and moody Behaviour Withdraw from people Maladaptive thoughts lead to negative emotions, which predisposes the person to develop mental health conditions. Cognitive Behavioural Perspective Cognitive Behaviour Therapy: Helps patients restructure their negative thought patterns to modulate their emotions and thereby acquire adaptive behaviour. Powerful impact on contemporary clinical psychology. Strongly supported by empirical evidence. Social Perspective Social Perspective Factors with detrimental effects on a child’s socioemotional development Early deprivation or trauma Problems in parenting style Marital discord & divorce Low socioMaladaptive economic status Prejudice & peer & relationships discrimination unemployment Social perspective considers: how environmental factors can influence the occurrence of mental health conditions. programmes to improve social conditions. community facilities for the early detection, treatment, and long-range prevention. Cultural Considerations Consider how :  ideas about normal and abnormal differ in different places around the world.  individual personality development reflects the larger society.  symptoms of psychiatric conditions are manifested in different cultures: somatic versus emotional presentation. Certain symptoms are consistently found among similarly diagnosed clinical groups (eg: schizophrenia). Prevalence of psychiatric conditions can vary widely across cultures (e.g., depression, alcohol and drug addictions). Protective Factors and Resilience Protective factors: Influences that modify person’s response. Resilience: Ability to successfully adapt to very difficult circumstances. Mental health professionals can harness patients’ protective factors and strengths to help them build up resilience against mental health conditions. References Ahmari, S. E., Spellman, T., Douglass, N. L., Kheirbek, M. A., Simpson, H. B., Deisseroth, K., Gordon, J. A., & Hen, R. (2013). Repeated cortico-striatal stimulation generates persistent OCD-like behavior. Science (New York, N.Y.), 340(6137), 1234–1239. https://doi.org/10.1126/science.1234733. Filippi, M., Canu, E., Gasparotti, R., Agosta, F., Valsecchi, P., Lodoli, G., Galluzzo, A., Comi, G., & Sacchetti, E. (2014). Patterns of brain structural changes in first-contact, antipsychotic drug-naive patients with schizophrenia. AJNR. American journal of neuroradiology, 35(1), 30–37. https://doi.org/10.3174/ajnr.A3583. Hooley, J.M., Nock, M.K. and Butcher, J.N. (2020) Abnormal Psychology, Global Edition (18th Ed.), Pearson. Geddes, J., Andreasen, N. C., & Goodwin, G. (2020). New Oxford Textbook of Psychiatry. 3rd Edition. Oxford, Oxford University Press. Low, L. et.al. (Models of Psychiatric Illness) In Sim, K., Sengupta, S., Fung, D. and Chee, K. T. (2014) Essential Guide to Psychiatry. Singapore, Pearson Education South Asia Pte Ltd. Murphy, T. K., Kurlan, R., & Leckman, J. (2010). The immunobiology of Tourette's disorder, pediatric autoimmune neuropsychiatric disorders associated with Streptococcus, and related disorders: a way forward. Journal of child and adolescent psychopharmacology, 20(4), 317–331. https://doi.org/10.1089/cap.2010.0043. Thank You! 80