There is some evidence to suggest that the role of genetic and environmental influences may vary for different types of psychiatric symptoms in childhood. The aim of this study was to examine to what extent genetic and environmental factors influence parent-rated conduct and neurotic symptoms in childhood and adolescence, using data obtained from a systematically ascertained sample of twins (198 same sex pairs) aged between 8 and 16 years. For symptoms of antisocial behaviour, transmission could be explained entirely by shared environmental factors. Social class effects were also found to have a significant influence on antisocial behaviour, although these effects only accounted for a small proportion of the variance explained by shared environmental factors. In contrast, transmission of neurotic symptoms was best explained by additive genetic influences alone with no contribution from shared environment. Non-shared environmental factors accounted for a substantial component of the variation for both antisocial behaviour and neurotic symptoms.

The Virginia Twin-Family Study of Adolescent Behavioral Development (VTSABD) is a current longitudinal study of psychopathology in 1412 pairs of 8–16-year-old Caucasian twins and their parents. The primary aim of the study is to evaluate family–genetic and environmental risk factors for major domains of psychopathology in families representative of the Virginia Caucassian population. In this report, we utilize census-derived indices of neighbourhood income and urban residence to identify departures from population representation arising at the time of family enrolment in the twin registry and family participation in a psychiatric interview. Furthermore, we consider whether demographic sample biases influenced prevalence rates of adult psychopathology (including major depression, generalized anxiety disorder, alcohol dependence, phobias, and panic disorder) in the VTSABD. Results indicated that families that enrolled in the twin registry (83% of those identified by Virginia schools) and that participated in the home interview (75% of those targeted) resided in urban and rural communities with a range of per capita income levels representative of the Virginia population. However, participation biases operated throughout the study and were primarily characterized by losses of families living in low income, urban communities. There was also a smaller number of families living in high income neighbourhoods that did not enrol in the twin registry or that indefinitely postponed the psychiatric interview. These biases had small effects on prevalence rates of adult psychopathology in the VTSABD sample, even though neighbourhood income was significantly related to a subset of adult diagnoses. We emphasize the usefulness of the census methodology in evaluating sample biases in population based psychiatric genetic studies.

Twin studies of psychiatric illness assume that the genetic and environmental risk factors for psychiatric illness are similar in twins and non-twins and in monozygotic (MZ) and dizygotic (DZ) twins. To test this assumption, we examine whether the treated incidence of psychiatric illness in twins deviates from population expectations or differs between MZ and DZ twins. Using first admissions to the Swedish Psychiatric Registry for the years 1979–83 for all twins born 1886–1958 from the Swedish Twin Registries, we calculated Standardized Morbidity Ratios (SMRs) using national incidence rates together with individually computed person-years at risk in the twin cohort. The diagnoses examined, for which there was more than 393000 person-years of risk, were schizophrenia, other non-affective psychoses (ONAP), bipolar affective illness (BPAI), unipolar affective illness (UPAI) and neurotic depression (ND). The SMRs (and 95% CIs) for all twins were: schizophrenia 0·86 (0·69–1·06), ONAP 1·05 (0·88–1·24), BPAI 1·09 (0·90–1·32), UPAI 1·05 (0·85–1·29) and ND 0·99 (0·88–1·10). This pattern of results did not differ substantially when examined separately by gender or birth cohort. Relative risks for first admissions for MZ v. same-sex DZ twins or same v. opposite-sex DZ twins did not differ significantly from unity for any of the disorders examined. In Sweden, the treated incidence of psychotic and affective disorders in twins does not differ from that found in the general population and does not differ across zygosity groups. These results support the validity of the twin method for the study of psychotic and affective disorders.

Recent studies have suggested that expanded CAG/CTG repeats contribute to the genetic aetiology of schizophrenia and bipolar disorder. However, the nature of this contribution is uncertain and difficult to predict from other known trinucleotide repeat diseases that display much simpler patterns of inheritance. We have sought to replicate and extend earlier findings using Repeat Expansion Detection in an enlarged sample of 152 patients with schizophrenia, 143 patients with bipolar disorder, and 160 controls. We have also examined DNA from the parents of 62 probands with schizophrenia or bipolar disorder. Our results confirm our earlier, preliminary findings of an association between expanded trinucleotide repeats and both schizophrenia and bipolar disorder. However, our data do not support the hypothesis that trinucleotide repeat expansion can alone explain the complex patterns of inheritance of the functional psychoses neither can this mechanism fully explain apparent anticipation.

Dieting is a widespread behaviour in developed countries, which in predisposed individuals can lead to the development of clinical eating disorders such as bulimia nervosa and anorexia nervosa. We studied the effect of moderate dieting in healthy women on the prolactin response to the serotonin (5-HT) receptor agonist, m-chlorophenylpiperazine (mCPP), a measure of the sensitivity of post-synaptic 5-HT2C receptors. Dieting significantly increased the prolactin response to mCPP and lowered plasma concentrations of the 5-HT precursor, tryptophan. We propose that dieting in women is associated with the development of functional supersensitivity of 5-HT2C receptors, probably in response to lowered levels of brain 5-HT. Alterations in brain 5-HT neurotransmission could play a part in dieting-induced dysregulation of eating and the development of clinical eating disorders in predisposed individuals.

The widely applied procedure of balancing self-report instruments by including positively and negatively keyed items is exemplified by the Zung Self-rating Depression Scale (SDS). Investigation of the influence of the symptom-positive and symptom-negative item modes on the SDS in a depressed population resulted in two major findings. First, the reversed scoring of the symptom-negative items resulted in higher mean item scores. Secondly, factor analyses of the SDS in the present study and in previous research revealed that the semantic modes of item presentation were represented in the factor structure of the SDS. These findings were confirmed by analyses with the State–Trait Anxiety Inventory (STAI) and by previous factor analytical research with balanced instruments and were interpreted within the framework of the theory of Positive and Negative Affect. The present data cast doubts on the construct validity of the SDS as a measure of depressive symptomatology due to the presence of the negatively keyed items and suggest reconsideration of the use of balanced instruments for minimization of the acquiescence response set.

We evaluate the long-term test–retest reliability and procedural validity of phobia diagnoses in the UM-CIDI, the version of the Composite International Diagnostic Interview, used in the US National Co-morbidity Survey (NCS) and a number of other ongoing large-scale epidemiological surveys. Test–retest reliabilities of lifetime diagnoses of simple phobia, social phobia, and agoraphobia over a period between 16 and 34 months were K = 0·46, 0·47, and 0·63, respectively. Concordances with the Structured Clinical Interview for DSM-III-R (SCID) were K = 0·45, 0·62, and 0·63, respectively. Diagnostic discrepancies with the SCID were due to the UM-CIDI under-diagnosing. Post hoc analysis demonstrated that modification of UM-CIDI coding rules could dramatically improve cross-sectional procedural validity for both simple phobia (K = 0·57) and social phobia (K = 0·95). Based on these results, it seems likely that future modification of CIDI questions and coding rules could lead to substantial improvements in diagnostic validity.

This analysis examines some of the psychological, philosophical and sociological motives behind the development of pauper lunatic asylum architecture in Ireland during the time of the Anglo–Irish union (1801–1922). Ground plans and structural features are used to define five psycho-architectonic generations. While isolation and classification were the prime objectives in the first public asylum in Ireland (1810–1814), a combination of the ideas of a psychological, ‘moral’, management and ‘panoptic’ architecture led to a radial institutional design during the next phase of construction (1817–1835). The asylums of the third generation (1845–1855) lacked ‘panoptic’ features but they were still intended to allow a proper ‘moral’ management of the inmates, and to create a therapeutic family environment. By the time the institutions of the fourth epoch were erected (1862–1869) the ‘moral’ treatment approach had been given up, and asylums were built to allow a psychological management by ‘association’. The last institutions (1894–1922) built before Ireland's acquisition of Dominion status (1922) were intended to foster the development of a curative society.

We studied the prolactin and cortisol responses to the 5-HT releasing agent, D-fenfluramine in 31 drug-free depressed patients and 29 healthy controls, using a double-blind, placebo-controlled design. There was no difference in either endocrine response between depressives and controls. Examining the sexes separately, or restricting comparisons to patients with melancholic depression, did not lead to any differences between the groups. Our findings suggest that in contrast to other 5-HT neuroendocrine probes such as L-tryptophan and clomipramine, the prolactin response to fenfluramine are not consistently blunted in depressed patients.

This study investigated psychosocial morbidity, coping styles and health locus of control in 64 cases with and without chronic fatigue identified from a cohort of primary care patients recruited 6 months previously with a presumed, clinically diagnosed viral illness. A significant association between chronic fatigue and psychosocial morbidity, somatic symptoms and escape-avoidance coping styles was shown. Chronic fatigue cases were significantly more likely to have a past psychiatric history and a current psychiatric diagnosis based on a standardized clinical interview. Twenty-three of the cases fulfilled criteria for chronic fatigue syndrome (CFS). Such cases were significantly more fatigued than those not fulfilling criteria, but had little excess psychiatric disorder. A principal components analysis provided some evidence for chronic fatigue being separable from general psychosocial morbidity but not from the tendency to have other somatic complaints. Past psychiatric history and psychological distress at the time of the viral illness were risk factors for psychiatric ‘caseness’ 6 months later, while presence of fatigue, psychologising attributional style and sick certification were significant risk factors for CFS. These findings extend a previous questionnaire study of predictors of chronic ‘post-viral’ fatigue.

This paper reports the results of a study designed to explore the validity of a shiftwork model of affective disorders. Fifty-five student nurses doing nightwork for the first time were recruited to a study designed both to replicate an earlier study of the effects of nightwork on cognitive, emotional and neurovegetative measures and to assess the effects of nightwork on personality measures and the role of personality factors and nightwork induced disturbances in predicting accommodation to nightwork. As in the earlier study, concentration, interest, energy, sleep and appetite were significantly disturbed by nightwork and there was an increased perception of recent criticism from others. The findings from both studies were, therefore, aggregated to explore further possible relations between outcomes and the pre-nightwork level of affective symptoms and sensitivity to interpersonal criticism. These predicted poor response. In contrast, measures of cognitive style and symptom interpretation did not predict outcome. The findings are not inconsistent with proposals that disturbance of circadian rhythms consequent on psychosocial disruptions may play a part in the genesis of or maintenance of depression. They also support a proposal that nightwork induced changes may be a suitable human model for investigation of aspects of the affective disorders.

A study was conducted, which simultaneously used GPs and epidemiological assessment procedures (MMSE, CAMDEX), to identify individuals with DSM-III-R dementia in the same population. In addition, a 1-year follow-up assessment was conducted in patients with a CAMDEX-diagnosis of dementia. In the non-institutionalized group, which was assessed both by the GP and with the epidemiological test battery, the prevalence of dementia according to the GP was 2·2%, whereas the prevalence based on the epidemiological approach amounted to 5·2%. In general CAMDEX-diagnoses of dementia were confirmed at 1-year follow-up, and thus the discrepancy between the two prevalence estimates must be attributed to the low sensitivity of the GPs. Sensitivity of the GP was related to help-seeking behaviour, with low sensitivity in patients with a low contact rate. It was also related to the use of less specific diagnostic labels by the GP (cognitive impairment), and to poor recognition of cognitive impairment in patients who visited their GP.

Patients suffering from persecutory delusions exhibit information processing and social reasoning biases that have been hypothesized to have a self-protective function. In a test of this hypothesis, patients suffering from persecutory delusions who were also depressed and non-depressed deluded subjects were compared with depressed and normal controls on two indirect assessments of self-schemata: the Dysfunctional Attitudes Scale (DAS) and incidental recall of negative and positive trait words that had previously been judged to be self-descriptive or not self-descriptive. Both the depressed subjects and the deluded subjects, whether or not they were depressed, scored highly on the DAS. Like normals, both depressed and non-depressed deluded subjects endorsed more positive than negative trait words as true of themselves whereas the depressed subjects endorsed as many negative as positive trait works. Like the depressed subjects, both groups of deluded subjects recalled as many of the negative words they had endorsed as positive words, whereas the normals remembered more positive words. No such bias was observed in subjects' recall of unendorsed words. The DAS results are interpreted as clearly consistent with a defensive model of persecutory delusions whereas the incidental recall data were equivocally so.

This study investigates the basis of individual variation in exposure to stressful life events (SLEs). A population based sample of 547 MZ and 390 DZ female–female twin pairs, aged between 17 and 55 years, were surveyed by two structured interviews, separated by at least 1 year, that enquired about SLEs experienced during the preceding 12 months. Data were analysed with a model that resolves occasion specific (‘random’) versus enduring (‘stable’) influences on SLEs. The latter is partitioned into that due to genetic, familial environmental and unique environmental factors. We demonstrate that both random factors and stable individual differences underlie variation in self-reported exposure to SLEs. For most network events this stable variance makes a relatively small contribution to the total variance in SLEs exposure and is almost entirely due to genetic or familial environmental effects. Stable individual differences are more important determinants of personal SLEs, and these reflect both familial factors as well as previous experiences unshared by relatives.

The paper of Anderson et al. (1993), based on cross-sectional data, showed that minor psychiatric disorder in a population is linearly related to the mean number of psychiatric symptoms in the population. The present investigation asks whether the same relationship holds longitudinally as well as cross-sectionally. Data from a 7-year follow-up of a general population sample demonstrate, for the first time, that a relationship exists between changes in prevalence of psychiatric disorder and changes in the mean number of psychiatric symptoms in a given population. Moreover, the relationship is linear; a one-point decrease in mean scores on the GHQ-30 is associated with a 6% decrease in prevalence of disorder.

Forty patients with obsessive–compulsive disorder (OCD) were compared to matched healthy controls on neuropsychological tests which are sensitive to frontal lobe dysfunction. On a computerized version of the Tower of London test of planning, the patients were no different from healthy controls in the accuracy of their solutions. However, when they made a mistake, they spent more time than the controls in generating alternative solutions or checking that the next move would be correct. The results suggest that OCD patients have a selective deficit in generating alternative strategies when they make a mistake. In a separate attentional set-shifting task, OCD patients were impaired in a simple discrimination learning task and showed a continuous cumulative increase in the number who failed at each stage of the task, including the crucial extra-dimensional set shifting stage. This suggests that OCD patients show deficits in both acquiring and maintaining cognitive sets.

The cognitive deficits in OCD may be summarized as: (i) being easily distracted by other competing stimuli; (ii) excessive monitoring and checking of the response to ensure a mistake does not occur; and (iii) when a mistake does occur, being more rigid at setting aside the main goal and planning the necessary subgoals. Both studies support the evidence of fronto-striatal dysfunction in OCD and the results are discussed in terms of an impaired Supervisory Attentional System.

A sample of 31 male and female depressed patients was interviewed to investigate spontaneous, intrusive memories of immediate and past life events. Previous findings that depressed patients experience high frequency intrusive memories were confirmed, as was an association between intrusive memories of childhood abuse and severity of depression. Patients reported intrusive memories for a variety of other events, particularly involving illness and death. Limited support was obtained for the hypotheses that the course of depression would be related to the activation of negative memories, and that immediate life events would trigger the activation of memories of similar events from the past.

Both motivational and defect theories have been offered to explain variations in insight among schizophrenic individuals but the results of tests of these theories have been inconclusive and inconsistent. The present study was designed to test the hypothesis that both motivation and cognitive deficits affect insight, with a trade-off between the two processes, giving rise to quadratic relationships between insight and cognitive deficits. Twenty-six schizophrenic patients completed battery of neuropsychological tests and participated in an interview designed to assess insight. In a multiple regression analysis predicting test results from insight scores, the linear component was non-significant while the quadratic component accounted for a highly significant 56% of the variance. Theoretical and clinical implications of this result are discussed briefly.