Epidemiology: reflections on testing the validity of psychiatric interviews.

Laboratory tests that validate psychiatric disorder are unavailable. Accordingly, the validity of structured diagnostic interviews such as the Diagnostic Interview Schedule have been assessed through a double-blind test-retest design. This approach compares the Diagnostic Interview Schedule to a clinician's assessment and evaluates its results by three statistics: sensitivity and specificity, for which the clinician's interview serves as the standard, and K, which measures concordance between the two interviews. This design is found wanting on several counts: the reinterview may be answered differently because of clinical change or because of its meaning to the respondent; the clinician's interview may be an erratic standard; and the statistics are affected by both prevalence and severity of disorder. Furthermore, the statistics may not predict the accuracy of prevalence estimates made by the interview or its ability to detect correlates of disorder. Some alternative approaches are suggested.

Psychiatric epidemiology.

To aid the President's Commission on Mental Health as well as the nonspecialist, the uses and developments of psychiatric epidemiology are briefly sketched. In the past few years, methods have been innovated that are capable of making differential diagnoses on a lifetime basis. We need instruments and tools that provide sufficiently detailed information to be of real use for prevention, intervention, and social policy; many such developments are now within our grasp. The problems are prospects of epidemiology, and needed administration and educational supports for future application to the question of who gets ill and why are discussed.

National Institute of Mental Health Diagnostic Interview Schedule. Its history, characteristics, and validity.

A new interview schedule allows lay interviewers or clinicians to make psychiatric diagnoses according to DSM-III criteria, Feighner criteria, and Research Diagnostic Criteria. It is being used in a set of epidemiological studies sponsored by the National Institute of Mental Health Center for Epidemiological Studies. Its accuracy has been evaluated in a test-retest design comparing independent administrations by psychiatrists and lay interviewers to 216 subjects (inpatients, outpatients, ex-patients, and nonpatients).

Drinking amid abundant illicit drugs. The Vietnam case.

We studied drinking patterns and problems of 451 US Army enlisted men after their return from Vietnam. Before Vietnam, nearly half were regular drinkers and one quarter had drinking problems. Problem drinking declined in Vietnam as opiate use rose sharply; half had tried opiates and 20% were opiate dependent. After Vietnam, opiate use decreased (now less than 2% opiate dependent) and problem drinking again became ascendant. At time of interview, 17% had drunk in an alcoholic pattern at some period in their lives and another 41% had had problems from drinking. The younger men were more likely to have had problems. Alcholism predictors included:becoming intoxicated at an early age; dropping out of school; truancy and expulsion from school; and having a father with a history of alcoholism or arrests.

Narcotic use in southeast Asia and afterward. An interview study of 898 Vietnam returnees.

From all US Army enlistees leaving Vietnam in September 1971, a random sample of 943 men was selected. Of these, 470 represented a "general" sample of all enlistees returning at that time, and 495 represented a "drug positive" sample whose urine samples had been positive for opiates at the time of departure. We attempted to locate and personally interview all of the men in the samples. Results indicate that before arrival, hard drug use was largely casual, and less than 1% had ever been addicted to narcotics. In Vietnam, almost half of the general sample tried narcotics and 20% reported opiate addiction. After return, usage and addiction essentially decreased to pre-Vietnam levels. We discuss the use of nonnarcotic drugs, predictors and correlates of drug use in the samples, and the relationship of drugs to post-Vietnam social adjustment.

Renard diagnostic interview. Its reliability and procedural validity with physicians and lay interviewers.

A psychiatric diagnostic interview that can be reliably and validly administered by nonpsychiatric physicians and lay interviewers has both research and clinical applications. We examined the interrater reliability and procedural validity of the Renard Diagnostic Interview (RDI), an instrument designed for these purposes. Randomly selected psychiatric inpatients were interviewed once by a psychiatrist using our standard departmental research interview and were then given RDIs by two psychiatrists, two lay interviewers, or one of each. The reliability of the RDI is estimated by examining diagnostic concordance for the two RDI interviews. Procedural validity is estimated by examining diagnostic concordance between the RDI and the traditional departmental interview. Both reliability and procedural validity were found to be high, and the study demonstrates that lay interviewers using the RDI after a brief period of training can obtain accurate diagnostic information.

Computer-assisted derivation of a screening interview for alcoholism.

A short screening interview for the diagnosis of alcoholism has been developed with the assistance of the automatic interaction detector (AID) program (a multivariate sequential analysis strategy) that is part of the OSIRIS statistical package. Retrospective and prospective tests of the effectiveness of the interview have shown that it permits a diagnosis of alcoholism with less effort than a larger, more comprehansive research interview. The performance of the screening and research interviews have been compared to assess the effects of severity of illness and reliability of individual replies on the diagnoses made by each interview.

Reliability of psychiatric diagnosis. I. A methodological review.

This article reviews some methodological aspects of studies of diagnostic reliability in psychiatry. We define and discuss the concept of interrater reliability and review some of the ways in which the design of the reliability study can influence the results. Three basic methodological issues are raised, including: importance of structured interviews and objective diagnostic criteria, the importance of a test/retest vs an interviewer/observer design, and the calculation of reliability in a way that takes chance agreement into account.

Evaluation of a screening interview for Briquet syndrome (hysteria) by the study of medically ill women.

A screening interview for Briquet syndrome consisting of 14 symptom questions was administered to a group of 50 medically ill women. No patient was found eligible for a diagnosis of Briquet syndrome, a frequency less than the estimated general population prevalence of 1% to 2%. When symptoms explainable by known organic disorder were considered positive, 14% of patients became eligible for the diagnosis. We consider this a low enough rate to allow screening by lay interviewers. A frequency distribution of symptoms comparing the medically ill women and a group of psychiatric clinic women with Briquet syndrome shows that the Briquet group had both more symptoms and distinctive patterns of symptoms.

A comparison of clinical and diagnostic interview schedule diagnoses. Physician reexamination of lay-interviewed cases in the general population.

We examined the level of agreement between diagnoses derived from data gathered by lay interviewers using the Diagnostic Interview Schedule (DIS) in a general population survey (the Epidemiologic Catchment Area project) and both DIS and clinical diagnoses made by psychiatrists. Overall percent agreement between the lay DIS and the psychiatrists clinical impression ranged from 79% to 96%. The chance-corrected concordance was .60 or better for eight of the 11 diagnoses. Specificities were all 90% or better. Sensitivities were lower, but lay results showed a bias for only two diagnoses: major depression was significantly underdiagnosed and obsessive illness was overdiagnosed. We compared the present results with those of previous studies from clinical settings. We explored possible reasons for disagreement and discussed the implications of the findings for psychiatric epidemiologic research.

The Composite International Diagnostic Interview. An epidemiologic Instrument suitable for use in conjunction with different diagnostic systems and in different cultures.

The Composite International Diagnostic Interview (CIDI), written at the request of the World Health Organization/US Alcohol, Drug Abuse, and Mental Health Administration Task Force on Psychiatric Assessment Instruments, combines questions from the Diagnostic Interview Schedule with questions designed to elicit Present State Examination items. It is fully structured to allow administration by lay interviewers and scoring of diagnoses by computer. A special Substance Abuse Module covers tobacco, alcohol, and other drug abuse in considerable detail, allowing the assessment of the quality and severity of dependence and its course. This article describes the design and development of the CIDI and the current field testing of a slightly reduced "core" version. The field test is being conducted in 19 centers around the world to assess the interviews' reliability and its acceptability to clinicians and the general populace in different cultures and to provide data on which to base revisions that may be found necessary. In addition, questions to assess International Classification of Diseases, ninth revision, and the revised DSM-III diagnoses are being written. If all goes well, the CIDI will allow investigators reliably to assess mental disorders according to the most widely accepted nomenclatures in many different populations and cultures.

The NIMH Epidemiologic Catchment Area program. Historical context, major objectives, and study population characteristics.

The National Institute of Mental Health multisite Epidemiologic Catchment Area (ECA) program is described in the context of four previous psychiatric epidemiologic surveys that included a combined total of 4,000 subjects from Stirling County, the Baltimore Morbidity Study, Midtown Manhattan, and the New Haven third-wave survey. The ECA program is distinguished by its sample size of at least 3,500 subjects per site (about 20,000 total); the focus on Diagnostic Interview Schedule--defined DSM-III mental disorders; the one-year reinterview-based longitudinal design to obtain incidence and service use data; the linkage of epidemiologic and health service use data; and the replication of design and method in multiple sites. Demographic characteristics of community and sample populations are provided for New Haven, Conn, Baltimore, and St Louis.

Lifetime prevalence of specific psychiatric disorders in three sites.

Lifetime rates are presented for 15 DSM-III psychiatric diagnoses evaluated in three large household samples on the basis of lay interviewers' use of the Diagnostic Interview Schedule. The most common diagnoses were alcohol abuse and dependence, phobia, major depressive episode, and drug abuse and dependence. Disorders that most clearly predominated in men were antisocial personality and alcohol abuse and dependence. Disorders that most clearly predominated in women were depressive episodes and phobias. The age group with highest rates for most disorders was found to be young adults (aged 25 to 44 years). Correlates with race, education, and urbanization are presented.

One-month prevalence of mental disorders in the United States. Based on five Epidemiologic Catchment Area sites.

One-month prevalence results were determined from 18,571 persons interviewed in the first-wave community samples of all five sites that constituted the National Institute of Mental Health Epidemiologic Catchment Area Program. US population estimates, based on combined site data, were that 15.4% of the population 18 years of age and over fulfilled criteria for at least one alcohol, drug abuse, or other mental disorder during the period one month before interview. Higher prevalence rates of most mental disorders were found among younger people (less than age 45 years), with the exception of severe cognitive impairments. Men had higher rates of substance abuse and antisocial personality, whereas women had higher rates of affective, anxiety, and somatization disorders. When restricted to the diagnostic categories covered in international studies based on the Present State Examination, results fell within the range reported for European and Australian studies.

Increasing brain tumor rates: is there a link to aspartame?

In the past two decades brain tumor rates have risen in several industrialized countries, including the United States. During this time, brain tumor data have been gathered by the National Cancer Institute from catchment areas representing 10% of the United States population. In the present study, we analyzed these data from 1975 to 1992 and found that the brain tumor increases in the United States occurred in two distinct phases, an early modest increase that may primarily reflect improved diagnostic technology, and a more recent sustained increase in the incidence and shift toward greater malignancy that must be explained by some other factor(s). Compared to other environmental factors putatively linked to brain tumors, the artificial sweetener aspartame is a promising candidate to explain the recent increase in incidence and degree of malignancy of brain tumors. Evidence potentially implicating aspartame includes an early animal study revealing an exceedingly high incidence of brain tumors in aspartame-fed rats compared to no brain tumors in concurrent controls, the recent finding that the aspartame molecule has mutagenic potential, and the close temporal association (aspartame was introduced into US food and beverage markets several years prior to the sharp increase in brain tumor incidence and malignancy). We conclude that there is need for reassessing the carcinogenic potential of aspartame.

Problems in follow-up studies.

Recent regulations concerning consent procedures and protection of privacy fall most severely on follow-up studies of childre. Indeed, rigorous sample selection, nearly complete follow-up, and objective assessment of outcome are virtually impossible now. Further, complicance with current "subjects' rights" regulations sometimes seems potentially more harmful to the subjects than is the research itself.

Depression in Viet Nam veterans and civilian controls.

In order to investigate the long-term psychological consequences of Viet Nam combat, the authors located and personally interviewed a group of 571 randomly selected Viet Nam veterans and 284 matched civilian controls 3 years after the veterans returned to the United States. In the veterans they found a weak association between combat and subsequent depressive symptoms, but the association did not persist after controlling for preservice factors. The incidence of depressive symptoms and syndromes was similar when veterans were compared with nonveterans. Results are contrasted with a 12-month follow-up study of the same veterans in which a stronger association between combat and later depression was found.

Retrospective postmortem dementia assessment. Validation of a new clinical interview to assist neuropathologic study.

Neuropathologic studies of dementia and normal aging suffer from a lack of individuals examined for the presence and severity of dementia before death. To increase clinical information in such cases, a retrospective collateral interview was developed. Thirty-nine individuals were studied; 27 had autopsies. In all cases, the autopsy confirmed the Retrospective Collateral Dementia Interview (RCDI) diagnosis of the presence or absence of dementia; the RCDI had a sensitivity of 88% and a specificity of 80% for specifically detecting probable Alzheimer's disease. Agreement between the RCDI and premortem diagnosis was 96%; between RCDI and medical records, 100%. Agreement between RCDI staging of dementia severity and the last assessment of the living subject was 70%; between the RCDI and a brief staging at death, 86%. This validation confirms the value of postmortem interviews with close informants to assess dementia presence and severity.

Diagnostic concordance between DSM-III, Feighner, and RDC.

The NIMH Diagnostic Interview Schedule was administered by psychiatrists to 216 individuals. The DSM-III, Feighner, and RDC diagnoses derived from the computerized interview results were then compared for eight psychiatric disorders. Rates of diagnostic concordance among the systems are given, and the causes of diagnostic discrepancies are discussed. Diagnostic concordance was highest for mania and alcoholism and lowest for schizophrenia and antisocial personality disorder. Implications of these findings and future research directions are discussed.

Cognitive impairment and length of hospital stay in older persons.

We looked at performance on the Folstein Mini-Mental State Exam (MMSE) as a predictor of hospitalization and length of stay in the coming year in community-dwelling older persons from the National Institute of Mental Health Epidemiologic Catchment Area program. They had been assessed with the MMSE at the outset and were re-evaluated with the MMSE and a Health Services Questionnaire 1 year later. Subjects were more likely to be hospitalized in the subsequent year if they were older than 75 years or if they scored poorly on the MMSE. Severe cognitive impairment increased the risk more than mild impairment. Multivariate analyses that controlled for demographic variables demonstrate that MMSE performance is a significant predictor of any subsequent hospitalization (medical or psychiatric) among whites and among those at both high and low educational levels. This effect was not explained solely by the increased rate of psychiatric hospitalizations. We also determined that a decline in MMSE score over 1 year was associated with an increased risk of hospitalization, more hospital days, longer average length of stay, and a prolonged (greater than 20 days) hospital stay. We conclude that both initial poor performance on the MMSE and deterioration increase the risk of hospital use and lead to more extended hospital stays. However, even with poor MMSE performance, most older persons remain out of the hospital and most of those hospitalized do not have prolonged stays; thus, MMSE score alone is insufficient as a predictor of impending hospitalization. Further studies are needed to add other measures of risk for hospitalization and prolonged hospital stays.