2004, Number 1
Salud Mental 2004; 27 (1)
Validez de constructo de un instrumento para la detección de factores de riesgo en los trastornos de la conducta alimentaria en mujeres mexicanas
Unikel C, Gómez-Peresmitré G
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ABSTRACTThe main purpose of this paper was to present the construct validity of an instrument for the detection of risk factors for eating disorders in Mexican adolescents and young women, such that professionals in this area have a reliable and valid instrument for the detection of risk factors with qualitative and quantitative specifications, for the discrimination of risk severity in conjunction with decision-making related to prevention and treatment. This has been a theoretical and practical issue lacking issue in our present socio-cultural context. As systematic research on eating disorders is recent in Mexico, and because the low prevalence of these diseases has limited the access to clinical populations, their cause may be explained based on other cultural context’s research findings. Therefore it has become an important task to enrich such information with the Mexican eating disordered women’s experience, related to cultural issues. It may appear reiterative to develop new assessment instruments for this purpose, considering that international workings are abundant and some of them have been already validated with Mexican populations, for instance the Eating Attitudes Test, a self-report screening test of the symptoms and concerns characteristic of eating disorders, and the Eating Disorders Inventory, that measures traits and symptom clusters presumed to have relevance for the understanding and treatment of eating disorders. However, it is important to highlight the cultural differences of a particular culture and their relationship to psychopathology. The results obtained in different cultures, question the universal meanings for psychological disorders challenging the validity of standardization for non-occidental cultures. These views support the development of appropriate assessment instruments in different cultures. The main contribution of this instrument is that it was developed based on the information provided by Mexican eating disordered patients in relation to the development of their illness.
Risk factors associated with the development of eating disorders were assessed in a sample of 332 Mexican adolescents and young women (average age 19.1 years, SD=3.8), high school and college students at public and private schools in Mexico City. The study was carried out in two phases: in the first, the individual (eating behaviors, body weight history, curriculum, dating and violence), psychosocial (self-esteem, body image, depression, personality traits, identity and sexuality) and sociocultural (interpersonal relationships, career choice and values towards the body) factors associated with the development of eating disorders were assessed using a qualitative methodology (in-depth interviews) with 10 Mexican eating disordered patients in treatment at the Eating Disorders Unit of the National Institute of Psychiatry Ramón del Fuente in Mexico City.
The data obtained from the first phase, was used to identify the most important issues reported by patients, and questions were developed to assess the different areas; this resulted in the development of a 273 question self-report instrument. The instrument included two types of measurements: questions specifically implemented for this study, and scales previously validated in Mexican populations, such as the CES-D, suicidal ideation scale, and the relationship with mother/father scale, the Pope self-esteem scale, and the Eating Disorders Inventory perfectionism, maturity fears and body dissatisfaction scales. The instrument was initially assessed with a pilot study to determine the correct comprehension of the items and its statistical discrimination, with 31 women diagnosed with eating disorders in treatment at the Eating Disorders Unit, and 30 normal controls with similar ages (X=22.5, SD=7.7), similar schooling curriculum in years (X=12.5, DE=3.3) and BMI (X=22.3, SD=3.6). To achieve these goals, independent samples t-tests were conducted between groups, considering as valid those items that were different at a .05 level. After the pilot study the instrument included 14 areas and 216 questions associated with the development of eating disorders; nevertheless, in this paper only the results from the validation analyses of the 8 Likert scales that comprise the instrument will be reported: depressive symptoms, suicidal ideation, self-esteem, psychological characteristics, relationships with brothers and sisters, with males, with mother and father. Afterwards, reliability analyses and factorial validation were conducted.
The results showed a high total internal consistency for all of the scales (Cronbach alphas between .80 and .94), with factorial distributions similar to those obtained in the previous analyses done with other Mexican populations, as well as an internal consistency of the subscales from moderate to high (Cronbach alphas between .60 and .94).
The depressive symptoms scale, showed a two-factor distribution that distinguished between depressive mood and somatic symptoms. The suicidal ideation scale obtained an appropriate internal consistency score and in accordance with previous research in Mexican populations, only one factor was obtained that explained a high percentage of the total variance. The self-esteem scale showed a factorial distribution very similar to the one previously obtained in Mexican adolescents, although not all of the statistical scores were adequate, for instance, in the family relationships and anger subscales (Cronbach alphas < .70). The psychological characteristics scale obtained a 4 factor distribution, eliminated the questions related to the measurement of perfectionism, kept the maturity fears questions, and, the cluster of questions that were originally directed to measure body image, yielded two subscales, one related to the actual aesthetical body model, and the other directly related to body dissatisfaction, all of which obtained good statistical scores of internal consistency and explained variance. The scale “Relationship with brothers and sisters”, and “Relationship with males” obtained good statistical scores, in a one factor structure that clustered positive and negative questions. The relationship with father scale, showed a 5-factor structure with an appropriate total internal consistency score; nevertheless, 2 of the 5 subscales: father’s criticism and father’s maltreatment were not conceptually coherent. In the opposite, the other 3 subscales were conceptually good but one of them had a low internal consistency (Fathers support). On the other hand, the distribution of the same questions in the relationship with mother scale had more conceptual coherence and good statistical scores. The only subscale that showed some problem was the one denominated “Worth”, it includes four questions: two refer to the daughter’s perception of her mother’s demands, and two refer to the daughter’s perception of the worth her mother recognizes in her. In both scales, the factor that obtained the highest internal consistency score was “positive affect”, that combines questions about the positive issues of the relationship with parents in regard to the expression of affection and interest in daughter’s activities.
From these analyses a new instrument for non-clinicians was developed directly from the Mexican population, with adequate reliability and validity scores for the sample studied. That will be helpful for the detection of people at risk for eating disorders, and for sub clinical and clinical eating disorder cases. Nevertheless, given its recent development it will have to be tested in future studies to confirm its utility for eating disorders’ research in Mexico.