Chapter 4 — Psychological Disorders

The four Ds are deviance (behaviour that is different, extreme, unusual, or bizarre), distress (unpleasant and upsetting to the person and to others), dysfunction (interfering with the person's ability to carry out daily activities in a constructive way), and danger (possibly dangerous to the person or to others).

DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) is published by the American Psychiatric Association and presents discrete clinical criteria indicating the presence or absence of disorders. ICD-10 (International Classification of Diseases, 10th revision) is prepared by the World Health Organisation and is the classification scheme officially used in India and elsewhere; it provides descriptions of clinical features and diagnostic guidelines for each disorder.

The diathesis-stress model states that psychological disorders develop when a diathesis (biological predisposition or aberration, which may be inherited) is set off by a stressful situation. It has three components: (1) a biological aberration (diathesis), (2) a vulnerability or predisposition to develop the disorder, and (3) the presence of pathogenic stressors. This model has been applied to anxiety, depression, and schizophrenia.

Obsessive behaviour is the inability to stop thinking about a particular idea or topic; the person often finds these thoughts unpleasant and shameful. Compulsive behaviour is the need to perform certain behaviours over and over again — many compulsions deal with counting, ordering, checking, touching, and washing.

Schizophrenia symptoms are grouped into positive symptoms (pathological excesses such as delusions, disorganised thinking and speech, hallucinations, and inappropriate affect), negative symptoms (pathological deficits such as poverty of speech or alogia, blunted or flat affect, loss of volition or avolition, and social withdrawal), and psychomotor symptoms (such as catatonic stupor, catatonic rigidity, or catatonic posturing).

According to the chapter, low activity of the neurotransmitter GABA (gamma aminobutyric acid) has been linked to anxiety disorders, excess activity of dopamine to schizophrenia, and low activity of serotonin to depression.

The three types are: (1) specific phobias — irrational fears related to a specific object, animal, or enclosed space; (2) social anxiety disorder (social phobia) — intense fear and embarrassment when dealing with others; and (3) agoraphobia — fear of entering unfamiliar situations, often causing people to be afraid of leaving their home.

In somatic symptom disorder, the person has persistent body-related symptoms (which may or may not relate to a medical condition) and is overly preoccupied with those symptoms, making frequent visits to doctors. In illness anxiety disorder, the person is persistently preoccupied with the possibility of developing a serious illness; anxiety about one's health is the main concern rather than physical symptoms themselves. Both are concerned with medical illness but differ in how that concern is expressed.

Dissociative identity disorder, often referred to as multiple personality, is the most dramatic of the dissociative disorders. The person assumes alternate personalities that may or may not be aware of each other. It is often associated with traumatic experiences in childhood.

The two main features of Attention-Deficit/Hyperactivity Disorder (ADHD) are inattention (difficulty sustaining mental effort during work or play, not following instructions, being easily distracted, and not finishing assignments) and hyperactivity-impulsivity (inability to control immediate reactions, difficulty waiting or taking turns, constant motion, and difficulty resisting immediate temptations).

Intellectual disability refers to below-average intellectual functioning with an IQ of approximately 70 or below, combined with deficits or impairments in adaptive behaviour (in areas such as communication, self-care, home living, social and interpersonal skills, functional academic skills, and work), which are manifested before the age of 18 years.

The three eating disorders are: (1) anorexia nervosa — the individual has a distorted body image, often refuses to eat, exercises compulsively, and may starve to death; (2) bulimia nervosa — the individual binges on food then purges using laxatives, diuretics, or vomiting; and (3) binge eating — frequent episodes of out-of-control eating past the point of fullness, often when not hungry.

Post-traumatic stress disorder (PTSD) can occur in people who have been caught in a natural disaster (such as a tsunami), been victims of terrorist bomb blasts, been in a serious accident, or been in a war-related situation. Symptoms may include recurrent dreams, flashbacks, impaired concentration, and emotional numbing.

A previous suicidal attempt is stated as the strongest risk factor for suicide. Other risk factors include mental disorders (especially depression and alcohol use disorders), going through natural disasters, experiencing violence, abuse or loss, and isolation at any stage of life.

Yes — this chapter is part of the NCERT Class 12 Psychology textbook, which is freely available as a PDF on the official NCERT website (ncert.nic.in) with no registration or sign-up required.