Ricardo Araya - Academia.edu (original) (raw)

Papers by Ricardo Araya

Contraception, 2003

The ability of cupric ions to immobilize human spermatozoa was assessed in vitro using an optical... more The ability of cupric ions to immobilize human spermatozoa was assessed in vitro using an optical microscope. A Ringer's solution containing human spermatozoa and three cupric ion concentrations of 8 x 10(-8) mol/L, 8 x 10(-6) mol/L and 8 x 10(-5) mol/L were tested. The higher cupric ion concentrations (8 x 10(-5) mol/L and 8 x 10(-6) mol/L) significantly reduced spermatozoa motility after about 20 min. However, with the lower cupric ion concentration tested (8 x 10(-8) mol/L), also for 20-min experimentation, the reduction in motility was more limited.

British Journal of Psychiatry, 1994

The aims were to determine the prevalence of psychiatric morbidity among primary care attenders i... more The aims were to determine the prevalence of psychiatric morbidity among primary care attenders in a poor suburb of Santiago and to study the relationship with health service use. A cross-sectional survey was made of 163 consecutive attenders to a primary care clinic. Eleven per cent of the sample gave a psychological reason for consultation and the prevalence of psychiatric morbidity was 53%, defined using the revised Clinical Interview Schedule. Women and those of lower socio-economic status were at higher risk. Physicians recognised 14% of the psychiatric morbidity. Attenders with psychiatric morbidity consulted more frequently. There is a need to improve the recognition and management of psychiatric morbidity in primary care in Chile and other less developed countries. This could lead to the more efficient use of scarce health care resources in primary care.

Social Science & Medicine, 2006

There has been much speculation about a possible association between the social and built environ... more There has been much speculation about a possible association between the social and built environment and health, but the empirical evidence is still elusive. The social and built environments are best seen as contextual concepts but they are usually estimated as an aggregation of individual compositional measures, such as perceptions on trust or the desirability to live in an area. If these aggregated compositional measures were valid measures, one would expect that they would evince correlations at higher levels of data collection (e.g., neighbourhood). The aims of this paper are: (1) to investigate the factor structure of a self-administered questionnaire measuring individual perceptions of trust, social participation, social cohesion, social control, and the built environment; (2) to investigate variation in these factors at higher than the individual level (households and postcodes) in order to assess if these constructs reflect some contextual effect; and (3) to study the association between mental health, as measured by the General Health Questionnaire-12 (GHQ-12), and these derived factors. A cross-sectional household survey was undertaken during May-August 2001 in a district of South Wales with a population of 140,000. We found that factor analysis grouped our questions in factors similar to the theoretical ones we had previously envisaged. We also found that approximately one-third of the variance for neighbourhood quality and 10% for social control was explained at postcode (neighbourhood) level after adjusting for individual variables, thus suggesting that some of our compositional measures capture contextual characteristics of the built and social environment. After adjusting for individual variables, trust and social cohesion, two key social capital components were the only factors to show statistically significant associations with GHQ-12 scores. However, these factors also showed little variation at postcode levels, suggesting a stronger individual determination. We conclude that our results provide some evidence in support of an association between mental health (GHQ-12 scores) and perceptions of social capital, but less support for the contextual nature of social capital. r

British Medical Journal, 2004

Social Science & Medicine, 2005

Most studies throughout the world have found that women report more psychological symptoms than m... more Most studies throughout the world have found that women report more psychological symptoms than men. Much less is known about possible variation between countries in the magnitude of these sex differences or the factors contributing to the increase of risk among women in countries with different levels of development. This study aimed to compare sex differences for common affective disorders (CAD) between Great Britain and Chile based on two large urban cross-sectional psychiatric household surveys that used similar methodology. Women in both countries reported more CAD than men but Chilean women had an increased risk in comparison to their British counterparts, a difference that became larger as symptom severity increased. Of all the main explanatory variables included in the analysis--education, employment status, children at home, marital status, and social support-the only statistically significant interaction that could account for this increased risk was education, with an increasingly larger risk for women with lower levels of educational attainments in Chile compared to Britain. Education is a powerful socioeconomic indicator that is difficult to revert later in life, especially in countries where opportunities for women are less forthcoming, and it might act as powerful reminder of social entrapment.

Journal of Environmental Psychology, 2005

The effect of the built environment on the quality of life of its residents is of growing interes... more The effect of the built environment on the quality of life of its residents is of growing interest. To investigate this properly, a method for measuring the physical condition of residential areas is required and this paper describes the development of such a tool. The Residential Environment Assessment Tool (REAT) is designed as a survey instrument, to be completed by an independent observer, to produce a contextual measure of a neighbourhood, reflecting both physical aspects and also the extent to which residents have established territoriality over the area. The tool is based on 28 items which are aggregated to give a total score, ranging between 0 and 68, and subdivided into 5 different domains to reflect different aspects of the environment. Inter-observer comparisons show that the tool is reliable, with kappa coefficients for most of the item scores exceeding 0.9. To investigate its validity the results were compared with responses to a detailed survey of individual residents and significant positive associations were found between most relevant items. The tool is being used for studies involving common mental disorders in the community and should be valuable for local authorities in targeting interventions to improve the physical condition of their area.

Social Psychiatry and Psychiatric Epidemiology, 1992

The General Health Questionnaire (GHQ-12) and the Self Report Questionaire (SRQ-20) were simultan... more The General Health Questionnaire (GHQ-12) and the Self Report Questionaire (SRQ-20) were simultaneously validated against the criterion of the Revised Clinical Interview Schedule (CIS-R) in a primary care clinic in Santiago, Chile. A Relative Operating Characteristic (ROC) analaysis was used to determine the optimal threshold point for case definition and to compare the performance of these two questionnaires. The validation coefficients for the GHQ-12 and the SRQ-20 were, respectively: sensitivity 76% and 74%; specificity 73% and 77%; overall misclassification rate: 26% and 25%. Misclassification by these questionnaires was significantly associated with education and sex, males being more likely than females to be misclassified as false negatives and poorly educated respondents as false positives. The symptom response profile of both questionnaires showed that the most prevalent items were psychological complaints of anxiety and depression. Both instruments seem to have a similar ability to identify minor psychiatric disorders in primary care in Chile.

Psychological Medicine, 2008

Background. Screening of patients for common mental disorders (CMDs) is needed in primary-care ma... more Background. Screening of patients for common mental disorders (CMDs) is needed in primary-care management programmes. This study aimed to compare the screening properties of five widely used questionnaires.

Lancet, 2010

Depression and anxiety disorders are common mental disorders worldwide. The MANAS trial aimed to ... more Depression and anxiety disorders are common mental disorders worldwide. The MANAS trial aimed to test the effectiveness of an intervention led by lay health counsellors in primary care settings to improve outcomes of people with these disorders.

Psychological Medicine, 1998

Factor analysis has been employed to identify latent variables that are unifying constructs and t... more Factor analysis has been employed to identify latent variables that are unifying constructs and that parsimoniously describe correlations among a related group of variables. Confirmatory factor analysis is used to test hypothesized factor structures for a set of variables; it can also, as in this paper be used to model data from two or more groups simultaneously to determine whether they have the same factor structure. Non-psychotic psychiatric morbidity, elicited by the Revised Clinical Interview Schedule (CIS-R), from four culturally diverse populations was compared. Confirmatory factor analysis was employed to compare the factor structures of CIS-R data sets from Santiago, Harare, Rotherhithe and Ealing. These structures were compared with hypothetical one and two factor (depression-anxiety) models. The models fitted well with the different data sets. The depression-anxiety model was marginally superior to the one factor model as judged by various statistical measures of fit. The two factors in depression-anxiety model were, however, highly correlated. The findings suggest that symptoms of emotional distress seem to have the same factor structure across cultures.

Psychological Medicine, 1992

Many of the standardized interviews currently used in psychiatry require the interviewer to use e... more Many of the standardized interviews currently used in psychiatry require the interviewer to use expert psychiatric judgements in deciding upon the presence or absence of psychopathology. However, when case definitions are standardized it is customary for clinical judgements to be replaced with rules. The Clinical Interview Schedule was therefore revised, in order to increase standardization, and to make it suitable for use by 'lay' interviewers in assessing minor psychiatric disorder in community, general hospital, occupational and primary care research. Two reliability studies of the revised Clinical Interview Schedule (CIS-R) were conducted in primary health care clinics in London and Santiago, Chile. Both studies compared psychiatrically trained interviewer(s) with lay interviewer(s). Estimates of the reliability of the CIS-R compared favourably with the results of studies of other standardized interviews. In addition, the lay interviewers were as reliable as the psychiatrists and did not show any bias in their use of the CIS-R. Confirmatory factor analysis models were also used to estimate the reliabilities of the CIS-R and self-administered questionnaires and indicated that traditional measures of reliability are probably overestimates.