NCERT Solutions for Class 12 Psychology Chapter 4: Psychological Disorders
These Class 12 Psychology Chapter 4 solutions cover Psychological Disorders from the NCERT textbook, updated for the 2026–27 session. The chapter explores the meaning of abnormality (the ‘four Ds’), the historical and modern models used to explain abnormal behaviour, the factors that underlie it, and the major psychological disorders classified by the ICD-10 (WHO) and DSM-5 (APA) — anxiety, obsessive-compulsive, trauma- and stressor-related, somatic symptom, dissociative, depressive, bipolar, schizophrenia spectrum, neurodevelopmental, disruptive/conduct, feeding and eating, and substance-related disorders. Below you get step-by-step answers to all Review Questions, key terms, extra practice, MCQs, Assertion–Reason and FAQs.
Chapter 4, Psychological Disorders, introduces abnormal psychology — the study of maladaptive behaviour, its causes, consequences and treatment. Abnormality is identified through the ‘four Ds’: deviance, distress, dysfunction and danger. The chapter traces the history of abnormal behaviour through three recurring perspectives — the supernatural, the biological/organic and the psychological — converging today into the bio-psycho-social approach. It explains the major models (biological, psychodynamic, behavioural, cognitive, humanistic-existential, socio-cultural and the diathesis-stress model) and the standard classification systems, the ICD-10 (WHO) and DSM-5 (APA). It then describes the major disorders: anxiety disorders, obsessive-compulsive and related disorders, trauma- and stressor-related disorders (PTSD), somatic symptom and dissociative disorders, depressive and bipolar disorders, schizophrenia, neurodevelopmental disorders (ADHD, autism, intellectual disability), conduct disorders, feeding and eating disorders, and substance-related and addictive disorders.
Key Terms & Concepts
Abnormal psychology: the area of psychology focused on maladaptive behaviour — its causes, consequences and treatment.
The four Ds: psychological disorders are deviant (unusual/bizarre), distressing (unpleasant to the person and others), dysfunctional (interfering with daily activities) and possibly dangerous.
Maladaptive behaviour: behaviour that cannot be modified according to the needs of the situation and interferes with the well-being, optimal functioning and growth of the individual.
Classification systems: the ICD-10 (International Classification of Diseases, by WHO, used in India) and the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, by the American Psychiatric Association).
Diathesis-stress model: disorders develop when a diathesis (an inherited biological predisposition/vulnerability) is set off by a stressful situation (pathogenic stressors).
Anxiety: a diffuse, vague, very unpleasant feeling of fear and apprehension; types include generalised anxiety disorder, panic disorder, phobias (specific, social, agoraphobia) and separation anxiety disorder.
Obsessions vs compulsions: obsessions are persistent, unwanted thoughts the person cannot stop; compulsions are repetitive acts the person feels driven to perform (washing, checking, counting).
Dissociation: a severance of connections between ideas and emotions, with feelings of unreality, depersonalisation and loss/shift of identity (amnesia, fugue, dissociative identity, depersonalisation/derealisation).
Schizophrenia symptoms:positive (delusions, hallucinations, disorganised speech), negative (alogia, flat/blunted affect, avolition, social withdrawal) and psychomotor (catatonia).
Eating disorders: anorexia nervosa (distorted body image, self-starvation), bulimia nervosa (binge then purge) and binge-eating disorder.
Review Questions — Full Solutions
All questions below are reproduced verbatim from the NCERT textbook’s end-of-chapter Review Questions. Answers are original, written in exam-ready style.
1. Identify the symptoms associated with depression and mania.
ANSWERSymptoms of depression (major depressive disorder): a period of depressed mood and/or loss of interest or pleasure in most activities, along with a change in body weight or appetite, constant sleep problems (insomnia or oversleeping), tiredness and loss of energy, inability to think clearly or concentrate, agitation or greatly slowed behaviour, excessive guilt or feelings of worthlessness, and recurring thoughts of death and suicide.Symptoms of mania: a manic episode is marked by an elevated, euphoric or irritable mood with greatly increased energy and activity. The person shows inflated self-esteem or grandiosity, a decreased need for sleep, becomes unusually talkative, has racing thoughts and is easily distractible, and engages in excessive, risky or impulsive activities. In Bipolar I disorder, manic episodes alternate with episodes of depression, sometimes interrupted by periods of normal mood.
2. Describe the characteristics of children with hyperactivity.
ANSWERHyperactivity is one of the two main features of Attention-Deficit/Hyperactivity Disorder (ADHD), the other being inattention. Children with hyperactivity seem to be in constant motion and are often described by parents and teachers as ‘driven by a motor’, always on the go.They find it impossible to sit still through a lesson; they fidget, squirm, climb and run around the room aimlessly, and talk incessantly. Closely linked is impulsivity — such children are unable to control their immediate reactions or to think before they act. They find it difficult to wait or take turns, cannot resist immediate temptations or delay gratification, and have minor mishaps such as knocking things over, with more serious accidents and injuries also occurring. These behaviours interfere with their academic, social and family functioning.
3. What are the consequences of alcohol substance addiction?
ANSWERPeople who abuse alcohol drink large amounts regularly and rely on it to face difficult situations. Eventually drinking interferes with their social behaviour and their ability to think and work.The body builds up a tolerance, so the person needs to drink ever greater amounts to feel its effects, and experiences withdrawal responses when they stop. Alcoholism destroys millions of families, social relationships and careers. Intoxicated drivers are responsible for many road accidents.It also seriously affects the children of persons with the disorder, who show higher rates of psychological problems — particularly anxiety, depression, phobias and substance-related disorders. Excessive drinking can seriously damage physical health. Ethyl alcohol depresses the central nervous system: it impairs judgment and inhibition, makes speech less clear, weakens memory, and increases motor difficulties so that people become unsteady, clumsy and have blurred vision — making activities like driving dangerous.
4. Can a distorted body image lead to eating disorders? Classify the various forms of it.
ANSWERYes. A distorted body image — seeing oneself as overweight even when one is not — can lead to serious eating disorders, which are of special interest among young people. The three main forms are:(i) Anorexia nervosa: the individual has a distorted body image that makes them see themselves as overweight. They often refuse to eat, exercise compulsively and develop unusual habits such as refusing to eat in front of others. The person may lose large amounts of weight and even starve themselves to death.(ii) Bulimia nervosa: the individual eats excessive amounts of food (a binge) and then purges the body by using laxatives or diuretics or by vomiting. The person often feels disgusted and ashamed when they binge, but is relieved of tension and negative emotions after purging.(iii) Binge eating: there are frequent episodes of out-of-control eating. The individual eats faster than normal and continues until uncomfortably full, often eating large amounts even when not feeling hungry.
5. “Physicians make diagnosis looking at a person’s physical symptoms”. How are psychological disorders diagnosed?
ANSWERUnlike physical illnesses, psychological disorders are diagnosed by identifying patterns of behaviour, thoughts and emotions and matching them against the clinical criteria laid down in standard classification systems.A classification of disorders is a list of categories of specific disorders grouped on the basis of shared characteristics. Two official manuals are used. The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition), published by the American Psychiatric Association, presents discrete clinical criteria that indicate the presence or absence of a disorder. The ICD-10 (International Classification of Diseases, 10th revision), prepared by the World Health Organisation and used officially in India, gives for each disorder a description of the main clinical features/symptoms, associated features and diagnostic guidelines.Thus, instead of looking only at physical symptoms, mental health professionals such as psychologists and psychiatrists assess the person’s symptoms, history and functioning and compare them with these standardised diagnostic criteria to identify the disorder and plan treatment.
6. Distinguish between obsessions and compulsions.
ANSWERBoth occur in obsessive-compulsive disorder (OCD), in which the person is unable to control a preoccupation with specific ideas or to prevent themselves from repeatedly carrying out particular acts.Obsessions are thoughts: obsessive behaviour is the inability to stop thinking about a particular idea or topic. The person finds these recurring thoughts to be unpleasant and shameful but cannot get rid of them.Compulsions are actions: compulsive behaviour is the need to perform certain behaviours over and over again. Many compulsions deal with counting, ordering, checking, touching and washing. In short, obsessions are persistent unwanted thoughts, while compulsions are the repetitive acts the person feels driven to perform, often to reduce the anxiety caused by the obsessions.
7. Can a long-standing pattern of deviant behaviour be considered abnormal? Elaborate.
ANSWERA long-standing pattern of deviant behaviour is not automatically abnormal — it depends on how we define abnormality. Two basic and conflicting views exist.The first view sees abnormal behaviour simply as a deviation from social norms: thoughts, emotions and behaviours that differ markedly from a society’s ideas of proper functioning are called abnormal. But this is criticised because a society’s norms grow from its culture and change over time, so what is ‘deviant’ varies across cultures and eras; it wrongly assumes that normality is nothing more than conformity to social norms.The second view sees abnormal behaviour as maladaptive: the best criterion is not whether society accepts the behaviour but whether it fosters the well-being and growth of the individual and the group. By this criterion, even conforming behaviour can be abnormal if it is maladaptive, while deviant behaviour need not be abnormal if it does not interfere with optimal functioning. Hence a long-standing deviant pattern is considered abnormal only when it is also distressing, dysfunctional and maladaptive — not merely because it differs from social norms.
8. While speaking in public the patient changes topics frequently, is this a positive or a negative symptom of schizophrenia? Describe the other symptoms of schizophrenia.
ANSWERFrequently changing topics while speaking is a positive symptom of schizophrenia. It reflects a formal thought disorder — loosening of associations (derailment) — in which the person rapidly shifts from one topic to another so that the normal structure of thinking becomes muddled and illogical.Schizophrenia symptoms fall into three categories: positive, negative and psychomotor.Positive symptoms (pathological excesses): delusions (false beliefs firmly held despite evidence — of persecution, reference, grandeur, control), disorganised thinking and speech (loosening of associations, neologisms, perseveration), heightened perception and hallucinations (most commonly auditory, but also visual, tactile, somatic, gustatory and olfactory), and inappropriate affect.Negative symptoms (pathological deficits): poverty of speech (alogia), blunted and flat affect, loss of volition (avolition — apathy and inability to start or finish actions), and social withdrawal.Psychomotor symptoms: reduced spontaneous movement, odd grimaces and gestures, which in extreme form become catatonia — catatonic stupor (remaining motionless and silent), catatonic rigidity (rigid upright posture) and catatonic posturing (holding awkward, bizarre positions).
9. What do you understand by the term ‘dissociation’? Discuss its various forms.
ANSWERDissociation can be viewed as a severance of the connections between ideas and emotions. It involves feelings of unreality, estrangement, depersonalisation, and sometimes a loss or shift of identity. Sudden temporary alterations of consciousness that blot out painful experiences are the defining characteristic of dissociative disorders. The main forms are:(i) Dissociative amnesia: extensive but selective memory loss with no known organic cause; the person cannot recall important personal information, often related to a stressful or traumatic event. Its sub-type, dissociative fugue, involves unexpected travel away from home, assumption of a new identity, and an inability to recall the previous identity.(ii) Dissociative identity disorder (multiple personality): the most dramatic form, often associated with traumatic childhood experiences, in which the person exhibits two or more separate and contrasting personalities that may or may not be aware of each other.(iii) Depersonalisation/derealisation disorder: a dreamlike state in which the person feels separated from the self and from reality; self-perception changes and the sense of reality is temporarily lost or altered.
10. What are phobias? If someone had an intense fear of snakes, could this simple phobia be a result of faulty learning? Analyse how this phobia could have developed.
ANSWERPhobias are irrational fears related to specific objects, people or situations. They often develop gradually or begin with a generalised anxiety disorder, and are grouped into three types: specific phobias (e.g. fear of a certain animal or enclosed space), social anxiety disorder/social phobia (intense fear and embarrassment in dealing with others), and agoraphobia (fear of entering unfamiliar situations or leaving home).An intense fear of snakes is a specific phobia, and yes, the behavioural model explains it as the result of faulty learning — what has been learned can also be unlearned.How it could have developed: through classical conditioning, if the sight of a snake (a neutral stimulus) was once paired with a frightening experience such as a sudden encounter or being bitten, so that snakes alone now trigger fear. Through operant conditioning, the fear is maintained because avoiding snakes reduces anxiety, and this relief negatively reinforces the avoidance. Through social (observational) learning, the person may have acquired the fear by watching a parent or friend react with terror to a snake and imitating that reaction.
11. Anxiety has been called the “butterflies in the stomach feeling”. At what stage does anxiety become a disorder? Discuss its types.
ANSWERAnxiety is a diffuse, vague, very unpleasant feeling of fear and apprehension. A normal level of anxiety — the ‘butterflies in the stomach’ before an exam, a dental visit or a performance — is expected and even motivates us to do our task well. Anxiety becomes a disorder when its levels are so high that they are distressing and interfere with effective, day-to-day functioning. The anxious individual then shows symptoms such as rapid heart rate, shortness of breath, dizziness, sweating, sleeplessness and tremors. The main types are:(i) Generalised anxiety disorder: prolonged, vague, unexplained and intense fears not attached to any particular object, with hypervigilance and motor tension.(ii) Panic disorder: recurrent anxiety attacks of intense terror, with an abrupt surge of anxiety and symptoms like breathlessness, palpitations, trembling, dizziness, chest pain and a fear of losing control or dying.(iii) Phobias: irrational fears of specific objects, people or situations — specific phobias, social anxiety disorder (social phobia) and agoraphobia.(iv) Separation anxiety disorder (SAD): developmentally inappropriate fear and anxiety about separation from attachment figures, common in children who fuss, scream or throw tantrums to avoid separation.
Extra Practice Questions
Short Answer Type Questions
Q1. What are the ‘four Ds’ of abnormality?
ANSWERThe four Ds are the common features of most definitions of abnormality: deviance (different, extreme, unusual or bizarre behaviour), distress (unpleasant and upsetting to the person and others), dysfunction (interfering with the ability to carry out daily activities) and danger (possibly dangerous to the person or others).
Q2. Name the two major classification systems for psychological disorders and the bodies that developed them.
ANSWERThe two systems are the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition), developed by the American Psychiatric Association (APA), and the ICD-10 (International Classification of Diseases, 10th revision), prepared by the World Health Organisation (WHO) and used officially in India.
Q3. What is the diathesis-stress model?
ANSWERThe diathesis-stress model states that psychological disorders develop when a diathesis (an inherited biological predisposition or vulnerability to a disorder) is set off by a stressful situation. Its three components are the diathesis, the resulting vulnerability or being ‘at risk’, and the presence of pathogenic stressors. It has been applied to anxiety, depression and schizophrenia.
Q4. What is post-traumatic stress disorder (PTSD)?
ANSWERPTSD is a trauma- and stressor-related disorder experienced by people who have been through a natural disaster, bomb blast, serious accident or war. Symptoms vary widely but may include recurrent dreams, flashbacks, impaired concentration and emotional numbing. Adjustment disorders and acute stress disorder fall in the same category.
Q5. List the neurotransmitters linked to anxiety, schizophrenia and depression.
ANSWERAbnormal activity of certain neurotransmitters is linked to specific disorders: anxiety disorders to low activity of GABA (gamma aminobutyric acid), schizophrenia to excess activity of dopamine, and depression to low activity of serotonin.
Long Answer Type Questions
Q1. Discuss the historical perspectives on abnormal behaviour and how they have converged in modern times.
ANSWERThree perspectives recur throughout the history of abnormal psychology. The supernatural view holds that abnormal behaviour is caused by evil spirits (bhoot-pret) or the devil (shaitan); exorcism and the shaman (ojha) were used to drive them out. The biological/organic view holds that strange behaviour arises because the body and brain are not working properly; the Greek physicians Hippocrates, Socrates and Plato developed the organismic approach, and Galen linked temperament to the four humours (blood, black bile, yellow bile, phlegm), paralleling the Indian doshas of vata, pitta and kapha. The psychological view holds that disorders are caused by inadequacies in how a person thinks, feels or perceives the world; the work of St. Augustine and later Johann Weyer during the Renaissance laid the groundwork for psychodynamic theories. The Age of Reason brought a scientific attitude, asylum reforms and deinstitutionalisation. In recent years these have converged into an interactional or bio-psycho-social approach, in which biological, psychological and social factors together influence the expression and outcome of psychological disorders.
Q2. Explain the various models used to explain abnormal behaviour.
ANSWERSeveral models explain abnormal behaviour. The biological model states that abnormal behaviour has a biochemical or physiological basis, linked to faulty genes, endocrine imbalances and abnormal neurotransmitter activity. The psychodynamic model (Freud) holds that behaviour is determined by unconscious psychological forces — the id, ego and superego — and that abnormal symptoms result from conflicts traceable to early childhood. The behavioural model states that normal and abnormal behaviours are both learned through classical conditioning, operant conditioning and social learning, and that what is learned can be unlearned. The cognitive model holds that abnormal functioning results from irrational assumptions, illogical thinking and overgeneralisations. The humanistic-existential model focuses on the failure to self-actualise and to take responsibility for giving meaning to one’s existence. The socio-cultural model stresses family structure, social networks, societal conditions and the labels and roles assigned to troubled people. Finally, the widely accepted diathesis-stress model combines a biological predisposition with stressful triggers. Modern practice integrates these into a bio-psycho-social approach.
Q3. Describe the major symptoms of schizophrenia under its three categories.
ANSWERSchizophrenia is a group of psychotic disorders in which personal, social and occupational functioning deteriorate due to disturbed thought, strange perceptions, unusual emotions and motor abnormalities. Its symptoms fall into three categories. Positive symptoms are pathological excesses: delusions (false beliefs of persecution, reference, grandeur or control), formal thought disorders (loosening of associations, neologisms, perseveration), hallucinations (perceptions without external stimuli — most commonly auditory, but also visual, tactile, somatic, gustatory and olfactory), and inappropriate affect. Negative symptoms are pathological deficits: alogia (poverty of speech), blunted and flat affect, avolition (loss of volition, apathy, inability to start or complete actions) and social withdrawal. Psychomotor symptoms include reduced spontaneous movement and odd grimaces or gestures, which in extreme form become catatonia — catatonic stupor, catatonic rigidity and catatonic posturing. Together these symptoms make schizophrenia a severely debilitating disorder.
MCQs & Assertion–Reason
1. The ‘four Ds’ used to define abnormality are deviance, distress, dysfunction and:
For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.
A-R 1. Assertion: A normal level of anxiety can be useful.
Reason: Anxiety becomes a disorder only when it is so high that it is distressing and interferes with effective functioning.
A-R 2. Assertion: Coal-like fossil reasoning aside, conforming behaviour can sometimes be considered abnormal.
Reason: By the maladaptive criterion, behaviour is abnormal if it interferes with optimal functioning and growth, even if society accepts it.
A-R 3. Assertion: Auditory hallucinations are the most common type in schizophrenia.
Reason: Hallucinations are false beliefs that are firmly held despite contrary evidence.
A-R 4. Assertion: Obsessions and compulsions are the same thing.
Reason: Obsessions are persistent unwanted thoughts, while compulsions are repetitive acts the person feels driven to perform.
A-R 5. Assertion: A specific phobia can be the result of faulty learning.
Reason: According to the behavioural model, fears can be acquired through classical conditioning, operant conditioning and social learning.
Answer key: 1-(A), 2-(A), 3-(C), 4-(D), 5-(A).
Exam Tips & Common Mistakes
How to score full marks in this chapter
Memorise the four Ds, the two classification systems (ICD-10 by WHO, DSM-5 by APA) and the three neurotransmitter links (anxiety–GABA, schizophrenia–dopamine, depression–serotonin). For schizophrenia, always organise your answer under positive, negative and psychomotor symptoms with examples. For comparison questions (obsessions vs compulsions, somatic symptom vs illness anxiety, anorexia vs bulimia), use a clear two-sided structure. Link disorders to the right models — phobias to the behavioural model, and use the diathesis-stress model wherever ‘causes’ are asked. Always note the difference between normal anxiety/depression and the clinical disorder.
Common mistakes to avoid
Confusing obsessions (thoughts) with compulsions (acts).
Mixing up hallucinations (false perceptions) with delusions (false beliefs).
Calling topic-shifting a negative symptom — it is a positive symptom (loosening of associations).
Confusing anorexia nervosa (self-starvation) with bulimia nervosa (binge then purge).
Treating any deviation from social norms as abnormal — it must also be distressing, dysfunctional and maladaptive.
Forgetting that the DSM-5 is by the APA while the ICD-10 is by the WHO and is used in India.
Frequently Asked Questions
What is Chapter 4 of Class 12 Psychology about?
Chapter 4, Psychological Disorders, explains the meaning of abnormality (the four Ds), the historical and modern models of abnormal behaviour, the factors underlying it, the ICD-10 and DSM-5 classification systems, and the major psychological disorders — anxiety, obsessive-compulsive, trauma-related, somatic, dissociative, depressive, bipolar, schizophrenia, neurodevelopmental, conduct, eating and substance-related disorders.
What is the difference between obsessions and compulsions?
Obsessions are persistent, unwanted thoughts that the person cannot stop and finds unpleasant or shameful, while compulsions are repetitive acts — such as washing, checking, counting or ordering — that the person feels driven to perform over and over again. Both occur in obsessive-compulsive disorder.
What is the exercise section for Chapter 4 of Class 12 Psychology?
The end-of-chapter exercise in NCERT Class 12 Psychology Chapter 4 is headed Review Questions and contains 11 questions, all answered step by step on this page.
