Psychological Disorders — Class 12 Psychology

This chapter explains how abnormal behaviour is identified, what causes it and the major psychological disorders. Most definitions of abnormality share the four Ds: deviance, distress, dysfunction and danger. Historical views ranged from supernatural to biological to psychological explanations. Disorders are classified by the DSM-5 (American Psychiatric Association) and the ICD-10 of the World Health Organization. Factors underlying abnormal behaviour include biological models (genetics, neurotransmitters such as GABA and dopamine), psychological models (psychodynamic, behavioural, cognitive and humanistic-existential) and the socio-cultural model; the diathesis-stress model holds that disorders develop when a biological or psychological vulnerability (diathesis) meets stress. Major disorders include anxiety disorders (generalised anxiety, panic disorder and phobias such as specific, social and agoraphobia), obsessive-compulsive and related disorders, trauma- and stressor-related disorders (PTSD), somatic symptom and related disorders, dissociative disorders (amnesia, identity, depersonalisation), depressive disorders (major depressive disorder), bipolar and related disorders, schizophrenia spectrum disorders (delusions, hallucinations, disorganised thinking), neurodevelopmental disorders (ADHD, autism spectrum disorder, intellectual disability), disruptive impulse-control and conduct disorders, feeding and eating disorders (anorexia nervosa, bulimia nervosa) and substance-related and addictive disorders. Understanding these disorders is the basis for the therapies covered in the next chapter.