Concordance Agreement. In twin studies, this term is used to indicate the proportion of twins in which, if one is affected by a disease (say schizophrenia), the other is also affected. Confusingly, there are several different methods of calculating concordance rates, some of which give higher values than others (and hence are favoured by geneticists). See Chapter 4 for an explanation.
Continuous performance test (CPT) A type of psychological test used to measure vigilance; participants sit at a computer screen and watch stimuli being flashed up before them, perhaps at a rate of one every second, and are required to press a key when seeing a particular target.
Coping skills enhancement A type of cognitive behaviour therapy for psychosis which has the primary aim of improving a patient’s coping skills.
Cotard syndrome A delusional syndrome in which extremely nihilistic delusions (for example, ‘I am dead’) predominate.
Culture-bound syndromes Psychiatric conditions which appear to be specific to one culture. Examples include koro (an illness suffered by Chinese people, usually males, who believe that their sexual organs are shrinking), latah (experienced by Indonesians, who develop an exaggerated startle response, which includes shouting rude words and mimicking the behaviour of those nearby) and witiko psychosis (a rare disorder in which Algonquian-speaking Indians of Canada believe themselves to be possessed by vampires). It has been argued that anorexia nervosa and chronic fatigue syndromes are Western culture-bound syndromes.
Deficit See Cognitive deficit
Delusion A bizarre or irrational belief. It has been difficult to find a definition of delusions that clearly distinguishes them from normal beliefs and attitudes. According to Karl Jaspers, delusions are held with extraordinary conviction, are not amenable to counter-argument, and have a bizarre or impossible content. However, Jaspers held that true delusions were also ununderstandable, in the sense that they cannot be understood as arising meaningfully from the individual’s personality and experiences.
Delusional disorder The term introduced in DSM-III-R to replace ‘paranoia’, and which indicates a psychotic illness in which delusions are present but other psychotic symptoms are absent.
Dementia praecox Literally, senility of the young. The term was used by Kraepelin to describe psychiatric disorders characterized by progressive intellectual deterioration. Later replaced by the term ‘schizophrenia’.
Dismissing or avoidant attachment style See Avoidant attachment style.
Distracting response (coping) style A response to dysphoric mood, in which the individual seeks out activities that distract attention from the mood. It has been shown that this kind of response reduces the duration and severity of dysphoria.
Dizygotic (DZ) twins Non-identical (fraternal) twins. DZ twins develop when two separate eggs are fertilized by two separate sperm and grow into two foetuses. In effect, they are sibs born at the same time. They have approximately 50 per cent of their DNA in common and may be either the same sex or of opposite sexes. A gene for psychiatric disorder inherited by one DZ twin need not necessarily be inherited by the other.
Dopamine One of the neurotransmitters found in the brain. Some theories of schizophrenia and manic depression propose that neural pathways that utilize dopamine are abnormal in these conditions.
Downward social drift The tendency for people with severe mental illness to live in poor social circumstances, usually because they are unable to work.
Dualism The belief that mental processes and brain processes are separate and consist of different substances: a non-material mind in the case of the former, and physical matter in the case of the latter. Although few scientists and philosophers claim to support this doctrine today, it has been surprisingly difficult to shake it from our heads. Many psychiatric theories are implicitly dualist.
Dysphoria Negative mood state
Electrodermal response A brief change in the electrical conductivity of the skin that occurs during exposure to a stressful event. Caused by sweating, the response can be easily measured using electrodes placed on the back of the hand.
Electroencephalography The technique of measuring changes in electrical potential (‘brain waves’) generated by neuronal activity from electrodes placed on the scalp.
Electromyography The technique of measuring changes in electrical potential in muscles as they become more or less active. This technique can be used to measure the subvocalization that accompanies inner speech.
Emotional circumplex A model of subjective emotional states, which proposes that these can all be accounted for by two dimensions of emotion. According to one version of this theory, the two fundamental dimensions of subjective emotion are pleasantness versus unpleasantness and the degree to which the individual is physiologically aroused. According to another, the two fundamental dimensions are positive affect and negative affect (this model has the implication that individuals can experience both positive and negative emotion at the same time).
Expressed emotion A term describing the emotional attitude of relatives or significant others towards patients suffering from mental illness. High expressed emotion is reflected in a high rate of critical comments, hostility, and/or emotional involvement (as indicated by extreme emotional responses and over-protective behaviour towards the patient). High expressed emotion relatives or significant others tend to score highly on measures of negative affective style. Low expressed emotion relatives or significant others, in contrast, might be described as very laid back.
Expressivity The extent to which genetic traits vary in the degree to which they are expressed by those carrying the relevant genes.
Extrapyramidal side effects The most obvious side effects of conventional neuroleptic medication, including Parkinsonian symptoms such as stiffness and tremor, dystonias (uncontrollable muscle spasms), akathisia and tardive dyskinesia.
Factor analysis A method of analysing correlations between many different measures, often used to assess which symptoms cluster together. Factor analysis reduces the matrix of correlations between the measures to a small number of factors or dimensions. Symptoms appearing together in the same factor often (although not invariably) ‘go together’. The number of factors corresponds to the number of different clusters of symptoms that occur in the patients studied.
There are many different methods of factor analysis, and the choice between them is often arbitrary. Therefore, although the technique looks highly objective, some degree of subjectivity sneaks in when researchers decide which method to use.
Family therapy A type of psychological treatment that involves the entire family. In the case of patients suffering from psychosis, this approach is used to reduce stress in the family, which is known to make the course of psychosis worse. Family members are educated about psychosis so that they do not criticize the member who is experiencing symptoms. The family is also taught ways of managing family conflicts. This approach does not imply that families are responsible for mental illness experienced by their members. Effective treatment usually takes at least nine months.
Flat affect An apparent absence of emotion; one of the negative symptoms of psychosis. In fact, the subjective emotional life of patients with flat affect appears to be normal, and the problem seems to be a difficulty in expressing emotion.
Functional imaging/scanning Any scanning method that is used to detect changing physiological functioning.
Functional magnetic resonance imaging (fMRI) A form of MRI scan that uses the BOLD response to measure the flow of oxygenated blood to different regions of the brain, thereby allowing the areas that are most active at any particular time to be identified.
Genome The entire genetic code contained in the strands of DNA in the twenty-three human chromosomes. Most cells in the human body have two sets, one derived from the mother and the other from the father, forming twenty-three pairs of chromosomes.
Hallucination Usually defined as a perception in the absence of an appropriate stimulus. The most common example is hearing a
voice when no one is present to account for it.
Heritability The proportion of variance in a trait that can be attributed to genes. Usually expressed as a percentage, so that a heritability of 100 per cent implies that the trait is completely genetic. Psychiatric geneticists often assume that high heritability values for psychiatric disorders leave little room for environmental influences. However, this assumption is incorrect (see Chapter 17 for an explanation).
High-risk study A type of study in which individuals thought to be at special risk of developing a disorder are followed up over a period of time to see if they actually become ill, and to identify factors that predict the development of illness. The most common variant of this type of research starts with young people known to be at genetic risk because they have a first-degree relative who is suffering from the disorder. However, high-risk groups can also be identified using psychological or behavioural indicators, for example by selecting individuals who score highly on questionnaire measures of schizotypal personality traits.
Homovanillic acid A metabolite of dopamine that can be measured in the cerebrospinal fluid.
Hypofrontality Reduced activation of the frontal lobes of the brain in response to demanding tasks. Normally, when we try to solve certain types of problems, the frontal lobes become engaged and demand more oxygenated blood. In hypofrontal individuals this effect is less marked. Some biological psychiatrists have argued that hypofrontality is a feature of schizophrenia.
Hypomania A subclinical form of manic symptomatology, defined in DSM-IV as a distinct period of ‘abnormally and persistently elevated, irritable or expansive mood’ accompanied by at least three additional symptoms such as inflated self-esteem, non-delusional grandiosity, decreased need for sleep, flight of ideas, distractibility or ‘excessive involvement in pleasurable activities that have a high potential for painful consequences’.
Hypomanic personality A personality type, in which hypomanic traits are a persistent feature.
Incidence The number of new cases of a disorder appearing within a particular population in a particular period.
Inner or private speech Speech that is addressed to the self, which occurs internally and which cannot be heard by other people. In other words, verbal thought. It is believed that children first learn to talk to themselves out loud, before internalizing this process. As the reader will be aware, most adults still talk to themselves out loud under some circumstances (a phenomenon which, by convention, is known as private speech), especially when stressed or alone.
Insight According to British psychiatrist Aubrey Lewis, ‘The correct attitude to morbid change in oneself, and moreover, the realization that the illness is mental’ (‘The psychopathology of insight’, British Journal of Medical Psychology, 14: 332– 48, 1934). Psychotic patients who do not believe that they have an illness requiring treatment are therefore said to lack insight. Conversely, patients are said to have insight when they agree with their doctor.
Internality–externality An important dimension along which attributions can be categorized. Internal attributions locate the cause of an event with the individual (for example, ‘I failed the exam because I’m not very bright’) whereas external attributions locate the cause of the event with other people (‘The examiner had it in for me’) or with circumstances (‘I was unable to revise because I had to go to my sister’s wedding’).
Linkage analysis A method for attempting to identify particular sites on particular chromosomes where genes responsible for a trait or illness reside.
Magnetic resonance imaging (MRI) A technique for constructing detailed images of the body, by placing the body in a very strong magnetic field in order to trick it to emit radio waves when the field is turned off. This approach can be used to generate spectacularly beautiful pictures of the structure of soft tissues, for example the brain.
Mania A state of very intense emotional, cognitive and behavioural disturbance, in which the individual may feel highly energetic, may act impulsively, and may be both euphoric and irritable. Although sometimes regarded as the opposite of depression, dysphoric (depressive) symptoms commonly occur during manic episodes. Mania is often accompanied by psychotic symptoms such as grandiose delusions and thought disorder.
Manic depression A term used by Kraepelin to describe any disorder in which abnormal mood is the main symptom. However, in recent years the term has been used to describe an illness in which the patient suffers from recurrent episodes of depression and mania. Now often (and misleadingly) called ‘bipolar disorder’ to distinguish it from ‘unipolar depression’ in which only episodes of depression occur.
Mentalizing Understanding the mental states (beliefs, desires and intentions) of other people.
Metacognition Cognition about cognition; in other words, one’s beliefs about one’s own mental processes.
Monozygotic (MZ) twins Identical twins formed when a fertilized egg splits in the uterus and grows into two separate foetuses. MZ twins have identical DNA and are always the same sex. Therefore, any genes for mental illness inherited by one MZ twin must be inherited by the other.
Negative symptoms Symptoms characterized by the absence of desirable behaviours or experiences; for example social withdrawal, flat affect, anhedonia and apathy (avolition).
Neuroleptic induced deficit syndrome (NIDS) Lack of motivation necessary to achieve even modest goals, an undesirable consequence of long-term neuroleptic treatment.
Neuroleptic malignant syndrome A side effect of neuroleptic medication, characterized by muscular rigidity, fever and fluctuating consciousness, which is often mistaken for a bacterial infection, and which is fatal if drugs are not promptly discontinued.
Neuroleptic (antipsychotic) medication The class of drugs, first identified in the late 1940s and early 1950s, which are known to have an ameliorative effect on positive symptoms, and to reduce the risk of psychotic relapse. They have numerous side effects.
Neuropsychological tests Psychological tests devised to detect different types of brain damage. Test designers administer a large number of tests to patients with different kinds of brain damage and select items on which patients suffering from the type of brain damage of interest perform poorly. In the case of certain types of diffuse damage, neuropsychological tests may be more sensitive than brain scans.
Normalizing strategy A strategy employed by therapists practising cognitive behaviour therapy with psychotic clients. Efforts are made to demystify psychosis and make it seem more ‘normal’. Patients may be educated about the prevalence of psychotic complaints in the population, and about similarities between psychotic experiences and normal mental states.
Operational definition A definition that specifies the method or rule used to measure a concept. For example, an operational definition of length would be something like ‘the number obtained when a ruler is laid alongside an object’. Operationalism was proposed as a philosophy of science by the physicist Percy Bridgeman in the 1930s. It was later embraced by some psychologists, especially behaviourists such as B. F. Skinner, as a way of making psychology more objective. It was the philosopher Carl Hempel who first suggested that some of the diagnostic arguments in psychiatry could be resolved by agreeing on operational definitions of different disorders. DSM-III (and subsequent revisions of the manual) took this route by attempting to specify precisely which symptoms are required for a diagnosis to be made.
Paranoia and paranoid These terms have a confusing history. First used by the Ancient Greeks to mean crazy or mad, they were reintroduced in the nineteenth century to describe a type of delusional disorder, a usage embraced by Kraepelin. During the era after the Second World War, when psychiatric diagnoses briefly became unfashionable among US psychiatrists, the term ‘paranoid’ was often used to describe persecutory beliefs that were not necessarily delusional; hence the ordinary-language definition given in the Shorter Oxford English Dictionary, ‘A tendency to suspect or distrust others or to believe oneself unfairly used’. DSM-III used
the term paranoia to refer to a pure delusional psychosis (Kraepelin’s concept) but the term delusional disorder was used in its place in DSM-III-R and DSMIV. However, paranoid personality disorder remains in DSM-IV as an axis-2 disorder, and is defined in a way that closely matches the ordinary-language definition given in the OED. In this book, the term ‘paranoid delusion’ is used to describe any delusional system in which themes of persecution are prominent.
Penetrance The extent to which people in possession of a particular allele or set of alleles are likely to have particular characteristics determined by those alleles. If penetrance is low, only a fraction of those carrying the crucial alleles will show the relevant traits. Not to be confused with expressivity.
Personality disorder Defined in the DSM system as ‘enduring patterns of perceiving, relating to, and thinking about the environment and oneself’. They are considered to be distinct from illnesses because they are present throughout adulthood, whereas the illnesses are episodic. In the DSM system, they are listed on a separate axis (axis 2) from psychiatric illnesses (axis 1).
Positive symptoms Symptoms that consist of experiences and behaviours that would preferably be absent, such as hallucinations and delusions.
Madness Explained Page 60
