Anxiety: its role in the history of psychiatric epidemiology.

BACKGROUND: The role played by anxiety in the history of psychiatric epidemiology has not been well recognized. Such lack of understanding retarded the incremental growth of psychiatric research in general populations. It seems useful to look back on this history while deliberations are being carried out about how anxiety will be presented in DSM-V. METHOD: Drawing on the literature and our own research, we examined work that was carried out during and after the Second World War by a Research Branch of the United States War Department, by the Stirling County Study, and by the Midtown Manhattan Study. The differential influences of Meyerian psychobiology and Freudian psychoanalysis are noted. RESULTS: The instruments developed in the early epidemiologic endeavors used questions about nervousness, palpitations, sweating, trembling, shortness of breath, upset stomach, etc. These symptoms are important features of what the clinical literature called 'manifest', 'free-floating' or 'chronic anxiety'. A useful descriptive name is 'autonomic anxiety'. CONCLUSIONS: Although not focusing on specific circumstances as in Panic and Phobic disorders, a non-specific form of autonomic anxiety is a common, disabling and usually chronic disorder that received empirical verification in studies of several community populations. It is suggested that two types of general anxiety may need to be recognized, one dominated by excessive worry and feelings of stress, as in the current DSM-IV definition of Generalized Anxiety Disorder (GAD), and another emphasizing frequent unexplainable autonomic fearfulness, as in the early epidemiologic studies.

Anxiety and depression: a 40-year perspective on relationships regarding prevalence, distribution, and comorbidity.

OBJECTIVE: Building on a report about the prevalence of depression over time, this paper examines historical trends regarding anxiety in terms of its prevalence, its distribution by age and gender, and its comorbidity with depression. Methods for conducting such time trend analysis are reviewed. METHOD: Representative samples of adults were selected and interviewed in 1952, 1970, and 1992. Logistic regressions were used for statistical analysis. RESULTS: Although twice as common as depression, the prevalence of anxiety was equally stable. Anxiety was consistently and significantly more characteristic of women than men. A re-distribution of rates in 1992 indicated that depression but not anxiety had significantly increased among younger women (P = 0.03). Throughout the study, approximately half of the cases of anxiety also suffered depression. CONCLUSION: The relationships between anxiety and depression remained similar over time with the exception that depression came to resemble anxiety as a disorder to which women were significantly more vulnerable than men. Social and historical factors should be investigated to assess their relevance to this change.

Multiple informants: mortality associated with psychiatric disorders in the Stirling County Study.

This paper applies new statistical procedures for analyzing multiple-source information about the relation of psychiatric diagnoses to mortality. The data come from the Stirling County Study, a longitudinal community investigation of adults, that collected multiple-source reports (self-report and physician-report) about psychiatric disorders. These reports are used as predictors of mortality risk over a 16-year follow-up period (1952-1968). Despite extensive efforts, one or both of these reports were sometimes missing. Missingness of self-report was related to demographic characteristics as well as to physician-reports of psychiatric diagnosis. The statistical procedures used here draw together into a single frame of reference both informant reports for the initial Stirling survey and relate these to mortality risk using weighted generalized estimating equation regression models for time to event data. This unified method has two advantages over traditional approaches: 1) the relative predictiveness of each informant can be assessed and 2) all subjects contribute to the analysis. The methods are applicable to other areas of epidemiology where multiple informant reports are used. The results for self-reports and physician-reports of disorders were comparable: Psychiatric diagnosis was associated with higher mortality, particularly among younger subjects.

Incidence of depression in the Stirling County Study: historical and comparative perspectives.

BACKGROUND: The Stirling County Study provides a 40-year perspective on the epidemiology of psychiatric disorders in an adult population in Atlantic Canada. Across samples selected in 1952, 1970 and 1992 current prevalence of depression was stable. This paper concerns time trends in annual incidence as assessed through cohorts selected from the first two samples. METHODS: Consistent interview data were analysed by a computerized diagnostic algorithm. The cohorts consisted of subjects at risk for a first depression: Cohort-1 (N = 575) was followed 1952-1970; Cohort-2 (N = 639) was followed 1970-1992. Life-table methods were used to calculate incidence rates and proportional hazards procedures were used for statistical assessment. RESULTS: Average annual incidence of depression was 4.5 per 1000 for Cohort-1 and 3.7 for Cohort-2. Differences by gender, age and time were not statistically significant. The stability of incidence and the similarity of distribution by gender and age in these two cohorts corresponds to findings about the two early samples. In contrast, current prevalence in the recent sample was distributed differently and showed an increase among women under 45 years. CONCLUSIONS: The stability of the incidence of depression emphasizes the distinctive characteristics of current prevalence in the recent sample and suggests that the dominance of women in rates of depression may have occurred among those born after the Second World War. The results offer partial support for the interpretation of an increase in depression based on retrospective data in other recent studies but they indicate that the increase is specific to women.

A 40-year perspective on the prevalence of depression: the Stirling County Study.

BACKGROUND: According to epidemiologic studies that use recall of lifetime episodes, the prevalence of depression is increasing. This report from the Stirling County Study compares rates of current depression among representative samples of adults from a population in Atlantic Canada. METHODS: Sample sizes were 1003, 1201, and 1396 in 1952, 1970, and 1992, respectively. The depression component of the study's method, the DPAX (DP for depression and AX for anxiety), was employed. The original procedure (DPAX-1) was applied in all years. A revision (DPAX-2) was used in 1970 and 1992. The Diagnostic Interview Schedule (DIS) was also used in 1992. RESULTS: With the DPAX-1, the overall prevalence of current depression was steady at 5% over the 2 early samples but declined in 1992 because of vernacular changes referring to dysphoria. The DPAX-2 gave a stable overall prevalence of 5% in the 2 recent samples, but indicated that women and younger people were at greater risk in 1992 than in 1970. The DIS, like the DPAX-2, found a current 1992 rate of 5% for major depressive episodes combined with dysthymia. Recalled lifetime rates using the DIS showed the same profile interpreted in other studies as suggesting an increase in depression over time. CONCLUSIONS: Three samples over a 40-year period showed a stable current prevalence of depression using the DPAX methods that was comparable in 1992 with the current rates using the DIS. This casts doubt on the interpretation that depression is generally increasing. Within the overall steady rate observed in this study, historical change was a matter of redistribution by sex and age, with a higher rate among younger women being of recent origin.

A comparison of diagnostic interviews for depression in the Stirling County study: challenges for psychiatric epidemiology.

BACKGROUND: High prevalence rates in psychiatric epidemiologic studies raise questions about whether data-gathering procedures identify transient responses rather than clinical disorders. This issue is explored relevant to depression using data from the Stirling County Study. METHODS: The study's customary method, the DPAX (DP for depression and AX for anxiety) was compared with the Diagnostic Interview Schedule (DIS), both of which were administered to a sample of 1396 subjects selected in 1992. Reasons for discordance were analyzed, and demographic correlates of responses to questions about dysphoria were examined. These lay-administered interviews were then compared with clinician-administered interviews that used the Structured Clinical Interview for DSM-III-R (SCID) with 139 subjects. The kappa statistic and logistic regression were used for statistical assessment. RESULTS: For the level of agreement between the DPAX and the DIS for current and lifetime depression, kappa = 0.40 and kappa = 0.33, respectively. Subjects diagnosed only by the DPAX tended to have less education than those diagnosed only by the DIS. Some idioms for dysphoria seemed to work better than others. Using SCID interviews as a clinical standard, the DPAX had 15% sensitivity and 96% specificity and the DIS had 25% sensitivity and 98% specificity. CONCLUSIONS: Comprehension of an interview can be improved by using multiple questions for dysphoria and a simpler mode of inquiry. Clinician-administered interviews tend to corroborate disorders identified in lay-administered interviews but suggest that survey methods underestimate prevalence. Further research is needed to evaluate the validity of both types of interviews, but evidence from a 16-year follow-up evaluation indicates that depression diagnosed by the DPAX is a serious disorder in terms of morbidity and mortality.

Nature of pathology: the character of danger implicit in functional impairment.

OBJECTIVE: To facilitate clinical and scientific consensus in definitions of psychiatric disorders and with regard to the nature and meaning of pathology more generally. METHOD: An essay based on a review of definitional problems encountered by psychiatric epidemiologists, with examples taken from selected studies of historic importance. A remedy is suggested and illustrated by experiences with its use in the Stirling County Study. RESULTS: A concept of pathology, termed for reference as "impairment-risk," is defined as the danger that functional impairment carries for subsequent health adversities. The concept is based on the classical notions of Rudolf Virchow, the empirical orientations of Adolf Meyer's psychobiology, the functional concepts of physiology, and the dynamics implied by evolutionary biology. The ideas embedded in "impairment-risk" are beginning to be represented in official classifications of mental disorders. CONCLUSIONS: Impairment-risk has potential in the further development of psychiatric epidemiology because of the connections made possible among neuroscience, genetics, general medicine, psychology, and the more empirical of the social and behavioural sciences.

Social science and psychiatric epidemiology. A difficult relationship.

The difficulty in the relationships among the social sciences, psychiatry and epidemiology is important because it inhibits incremental growth of scientific knowledge regarding human behavior. This in turn handicaps coping with social, psychological and cultural perturbations which currently threaten human existence. A major reason for the difficulty in the relationships is the presence of divergent views among the various relevant disciplines with regard to the nature of the scientific process. This article presents an outline of the scientific process modelled on those sciences which focus on living systems. Growth in scientific knowledge is seen to occur as a result of a spiral movement in which articulating conceptual and operational transactions alternate. A problem of our time is that parts of the spiral are often disengaged and conducted independently in a way that makes impossible the incremental synthesis of theory, hypotheses, premisses and data.

Relations over time between psychiatric and somatic disorders: the Stirling County Study.

A longitudinal study of a general population in Atlantic Canada provided information on associations between two broad categories of illness: somatic disorders and disorders involving depression and/or anxiety. Prevalence was investigated in a sample of 1,003 adults selected in 1952 and another sample of 1,094 adults selected in 1970. Using a cohort of 618 survivors from the 1952 sample who were followed up in 1968, the authors studied prevalence at the beginning and end of the 16-year period. Incidence was also investigated so that the strength of associations between prior illness of one type and subsequent illness of the other type could be assessed. Data were obtained by interviewing subjects with the same structured schedule at each time of investigation. In prevalence enumerations, psychiatric disorders were found to be significantly associated with somatic disorders. Prior somatic disorder was significantly associated with subsequent incidence of depression and/or anxiety and vice versa. The results did not, however, show one direction of influence ("psyche-to-soma" or "soma-to-psyche") to be markedly stronger than the other. The results mainly support the concept of "generalized vulnerability" and draw attention to the importance of recognizing comorbidity in diagnosis and clinical practice.

Depression and anxiety in relation to social status. A prospective epidemiologic study.

Longitudinal research in Stirling County, Atlantic Canada, indicated that during the 1950s and 1960s the prevalence of depression was significantly and persistently higher in the "low" socioeconomic status population than at other socioeconomic status levels. Anxiety was found to show a less clear picture. Incidence of depression after the study started was also higher among those who were initially in the low socioeconomic status group, supporting the view that the stress of poverty may be causally related to depression. There was also a trend for prior depression to be associated with subsequent downward social mobility, supporting the view that the concentration of depressed people at the lower end of the social hierarchy may result from handicapping aspects of the illness. Neither of these trends was statistically significant. More striking was evidence that, irrespective of socioeconomic status, depression carried a substantial risk for poor clinical course and outcome. Both depression and poverty tended to be chronic, and, accordingly, their association at the end of the study was influenced by their association at its beginning. The stability of the relationship between poverty and depression warrants the attention of caregivers and policymakers and raises new questions about strategies for the study of causal sequences.

Contributions of epidemiology to psychiatric thought.

As a result of trying to apply both science and humanism to psychological problems, psychiatry is exposed to a welter of confusing issues in which science and intuition are pitted against each other. A growing awareness of the importance of quantification in clinical research and theory construction is having the effect of increasing the polarization. It is suggested in this paper that Karl Jaspers' formulation of ërklaren and verstehen provide a conceptual frame by which orderly relationships can replace much of the confusion and polarization. It is further suggested that this line of thought can be implemented and developed by the use of epidemiologic strategies. Historic and recent examples from the literature are provided in order to illustrate how this can be done.

Community mental health and information underload.

As is generally recognized, the community mental health movement has run into many serious obstacles which have caused it to fall short of original expectations. Lack of needed information on the part of policy makers, planners, administrators and workers is presented in this article as comprising much of the problem. Scientific understanding with regard to the nature of both "community" and "mental health" have been deficient and often substituted by idealistic myths based on wishful thinking. In the case of "community," the problem has been an overall failure to generate appropriate research. In the matter of "mental health," the research has been extensive but unbalanced, with serious neglect of important areas subsumed by the social and behavioral sciences. A perspective for dealing with these problems is outlined based on the total spectrum of efforts society makes in the mental health field from curing to health promotion. Two illustrations for utilizing this perspective are given. The first shows the integration of primary prevention with the rest of the effort spectrum, and the second shows the total effort spectrum united by the common target of reducing prevalence.

Prodromes of depression and anxiety. The Stirling County study.

A longitudinal investigation of psychiatric epidemiology in a general population (the Stirling County study) has indicated that the incidence of depression and anxiety disorders is low relative to prevalence, because these disorders have long durations. In an average year approximately nine adults among 1,000 experience a first-ever episode of one of these disorders. Incident cases over the course of a 16-year follow-up were more likely to have had premonitory symptoms than to have been asymptomatic at the beginning of the study. Among the relatively small number of people who exhibited the clearest prodromal manifestations, incidence was 20 per 1,000 annually. It might be possible to intervene before such disorders become fully formed and persistent if the precursors are given attention.

Mortality risk and psychiatric disorders. Results of a general physician survey.

As part of the Stirling County Study (Canada), general physicians were interviewed to identify the psychiatric disorders experienced by a sample of adults selected in 1952. Based on information about vital status gathered 16 years later, we found that those with a psychiatric disorder at the beginning of the study experienced 1.6 times the expected number of deaths. The effect in regard to premature mortality and accidental deaths was particularly strong. Four of six categories of psychiatric diagnoses were significantly associated with mortality. In terms of standardized mortality ratios, depression had the highest and anxiety the lowest risk in this general population. The findings are discussed as providing historical background from the 1950s and 1960s for studying trends.

Incidence of depression and anxiety: the Stirling County Study.

Prevalence studies in psychiatric epidemiology out-number incidence investigations by a wide margin. This report gives descriptive information about the incidence of depression and anxiety disorders in a general population. Using data gathered in a 16-year follow-up of an adult sample selected as part of the Stirling County Study (Canada), the incidence of these types of disorders was found to be approximately nine cases per 1,000 persons per year. The data suggest that for every man who became ill for the first time with one of these disorders, three women became ill. Incidence tended to be higher among relatively young persons. These incidence rates are consistent with prevalence rates of approximately 10 per cent to 15 per cent for depression and anxiety disorders aggregated together, given an estimated average duration of illness of about 10 years. It is concluded that these incidence rates are fairly realistic in view of evidence that disorders of these types tend to be chronic.

Affective disorders and mortality. A general population study.

A 16-year prospective study of a general population sample indicates that those who had reported a depression and/or anxiety disorder at baseline experienced 1.5 times the number of deaths expected on the basis of rates for a large reference population. As part of the Stirling County Study (Canada), the information was gathered from 1003 adults through structured interviews and was analyzed by means of a diagnostic computer program. The risk for mortality was assessed using external and internal standards, controlling for the effects of age and sex as well as for the presence of self-reported physical disorders at baseline. Increased risk was found to be significantly associated with affective but not physical disorders and with depression but not generalized anxiety. When this evidence about mortality was combined with information about subsequent psychiatric morbidity among survivors, 82% of those who were depressed at baseline had a poor outcome.

Primary prevention of psychiatric disorders.

After a general discussion of factors involved in primary prevention of mental disorders, a case is described where community intervention aiming at reversing a process of social disintegration seemed to reduce the prevalence of anxiety and depression. Further experience with community development as an activity integrated into the functioning of a mental health centre is described. It was possible to encourage the growth of social networks that in turn led to several sustained organizations for self help and mutual aid. Even if this is promising from a preventive point of view, the effect upon mental health is not known. Repeated epidemiological studies in the area show a very stable prevalence level over time with high degree of chronicity and few new cases. This means that change in prevalence over a limited period of time only to a very small degree can be caused by primary prevention.