Chapter 16: Psychological Disorders
Defining, Classifying, andDiagnosing PsychologicalAbnormality
LEARNING OBJECTIVE 1 Identify the common features of most definitions of abnormal functioning, and describe howpsychological disorders are classified and diagnosed.
• The study of psychological disorders is usually calledabnormal psychology. Abnormal psychological functioningis a wide-ranging problem in this country.
• Definitions of psychological disorders often include the“four Ds”—deviance, distress, dysfunction, and danger.
• The Diagnostic and Statistical Manual of MentalDisorders (DSM) (current version DSM-IV-TR) is the leading classification system in North America.
Models of Abnormality
LEARNING OBJECTIVE 2 Describe the major models used bypsychologists to explain abnormal functioning.
• Clinicians use several major models to explain abnormalfunctioning, including the neuroscience, psychodynamic,cognitive-behavioural, humanistic-existential, sociocultural,and developmental psychopathology models.
• The neuroscience model views abnormal functioning asa result of malfunctions in brain structure or chemicalactivity. Malfunctions can be caused by injuries or otherfactors, including genetics or viruses.
• Psychodynamic theorists view abnormal functioningas the result of unconscious conflicts that may haveoriginated in our early development. Freud focused on fixations during the oral, anal, and phallic stages ofdevelopment, while other theorists have focused on difficulties in ego development or our relationships withothers.
• Behavioural theorists propose that abnormal behavioursdevelop via the same processes as more adaptivebehaviours: classical conditioning, operant conditioning,and modelling. Cognitive theorists believe that abnormalfunctioning can result from disordered thoughts,including basic irrational assumptions, specific upsettingthoughts, and illogical thinking processes.
• Humanists suggest that people are vulnerable to psychologicaldisorders when they develop inaccurate viewsof their worth or goals in life. Existentialist therapiesfocus on helping clients discover their personal freedomof choice and take responsibility for making choices.
• According the socio-cultural model, abnormal behaviouris best understood in light of the social, cultural, andfamily forces brought to bear on an individual. Importantfactors include social change, socio-economic classmembership, cultural background, social networks, andfamily systems.
• Developmental psychopathology theorists are interestedin how psychological disorders evolve, based on bothgenetics and early childhood experiences, and on howthose early patterns affect people’s functioning as theymove through later life stages.
Mood Disorders
LEARNING OBJECTIVE 3 Describe and differentiate majordepressive disorder and bipolar disorder.
• The key features in mood disorders are depression—a low, sad state—and mania—a state of breathlesseuphoria. Most people with a mood disorder suffer onlyfrom depression.
• People with major depressive disorder suffer a varietyof symptoms, including feelings of sadness and lackof interest, low levels of activity and productivity, negativeviews of themselves and their lives, and physicalailments.
• Today’s leading explanations for major depressive disorder point to neuroscientific, psychological, or socioculturalfactors. Many theorists believe that the variousexplanations should be combined.
• People with bipolar disorder experience not only thelows of depression, but also the highs of mania. In themanic state, they want constant excitement. They tendto show poor judgment and planning, hold inflated opinionsof themselves, and show a great deal of energy.
• Although genes and biological factors appear to playkey roles in the development of bipolar disorder, there isgrowing evidence that stress and certain kinds of environmentalevents also must occur in order for episodesto unfold.
Anxiety Disorders
LEARNING OBJECTIVE 4 Describe the various types of anxietydisorders, and explain some causes of these disorders.
• As a group, anxiety disorders are the most commonmental disorders in North America. Often, people withone type of anxiety disorder have another type as well.
• People with generalized anxiety disorder experiencepersistent feelings of worry and anxiety. Some cognitivetheorists suggest that this disorder arises in peoplewho hold certain dysfunctional or irrational assumptions,while others focus on the individual’s intoleranceof uncertainty. An important neuroscience explanationfocuses on gamma-aminobutyric acid, a neurotransmitterinvolved in fear reactions.
• People with social anxiety disorder display severe, persistent,and irrational fears of social or performancesituations. Some socio-cultural factors appear to beinvolved.
• People with phobias have a persistent and irrational fear of a specific object, activity, or situation. Behaviouralprinciples, including classical conditioning and modelling,provide the leading explanations for specificphobias.
• People with panic disorder have recurrent attacks ofterror. These panic attacks are sometimes accompaniedby agoraphobia—a fear of venturing into publicplaces. A neuroscience-cognitive explanation of thedisorder focuses on physical sensations producedby malfunctioning brain circuitry, which are thenmisinterpreted.
• People with obsessive-compulsive disorder feel overrunby recurrent thoughts that cause anxiety (obsessions)and by the need to perform repetitive actions to reducethis anxiety (compulsions). While cognitive-behaviouraltheorists focus on the role of learning in these behaviours,neuroscientists focus on abnormally low levelsof serotonin or abnormal functioning in specific brainregions.
• People with posttraumatic stress disorder (PTSD) aretormented by fear and related symptoms well aftera horrifying event has ended. Although extraordinarytrauma causes the disorder, not everyone who experiencessuch trauma develops PTSD. Differences in biologicalprocesses, personalities, childhood experiences,social support systems, and cultural backgrounds alsomake people more or less likely to respond to trauma bydeveloping the disorder.
Schizophrenia
LEARNING OBJECTIVE 5 Describe the features of schizophreniaand some theories of what causes it.
• Schizophrenia is a disorder in which people deteriorateinto a world of unusual perceptions, odd thoughts, disturbedemotions, and motor abnormalities. These peopleexperience psychosis, a loss of contact with reality.
• Positive symptoms of schizophrenia are “pathologicalexcesses” in behaviour. They include delusions, disorganizedthinking and speech, hallucinations, and inappropriateaffect.
• Negative symptoms, or “pathological deficits,” includepoverty of speech, fl at affect, loss of volition, and socialwithdrawal.
• People with schizophrenia also sometimes experienceunusual psychomotor symptoms, which in their mostextreme form are collectively called catatonia.
• Many theorists believe that people inherit a geneticpredisposition to schizophrenia. Two kinds of brainabnormalities might be inherited—biochemical abnormalitiesand abnormal brain structure.
• Although neuroscience explanations of schizophreniahave received by far the most research support, psychologicaland sociocultural factors may help to bring aboutschizophrenia in people with a biological predispositionto develop it.
Other Disorders
LEARNING OBJECTIVE 6 Discuss the features and possiblecauses of somatoform, dissociative, and personality disorders.
• A somatoform disorder is a pattern of physical complaintswith largely psychosocial causes. In conversiondisorder, somatization disorder, and pain disorderassociated with psychological factors, there is an actualchange in physical functioning. In hypochondriasis andbody dysmorphic disorder, people who are healthy mistakenlyworry that there is something physically wrongwith them.
• Theorists typically explain hypochondriasis and bodydysmorphic disorders much as they explain anxiety disorders,as resulting from classical conditioning, modelling,or misinterpretation of bodily cues. Psychodynamicand socio-cultural explanations have been offered forconversion, somatization, and pain disorders, but theseexplanations have failed to receive much researchsupport.
• Changes in memory that lack a physical cause are calleddissociative disorders. In dissociative amnesia, peopleare unable to recall important information about theirlives. In dissociative fugue, people not only forget theiridentities and their past lives, but also flee to a differentlocation. In dissociative identity disorder, people developtwo or more distinct personalities.
• Psychodynamic theorists believe that dissociative disordersare caused by repression, the most basic egodefence mechanism, but this view has not receivedstrong research support.
• People with antisocial personality disorder persistentlydisregard and violate others’ rights. Because of theirpotentially negative behaviour, such as lying, impulsiveness,and recklessness, they are frequently found inprison. According to behavioural theorists, this disordercan be learned through various means. Neuroscienceexplanations focus on brain factors, such as low serotonin levels, deficient frontal lobe functioning, and lowarousal in response to warnings.
• People with borderline personality disorder display greatinstability, including major shifts in mood, an unstableself-image, and impulsivity. This disorder is not wellunderstood, but a recent biosocial theory proposes thatit results from a combination of internal and externalforces.