A MODEL FOR EPIDEMIOLOGIC STUDIES ON MENT AL-HEALTH AND PSYCHIATRIC MORBIDITY

The aim of this paper is to preseryt the objectives, methodology and i nstrument used in a comprehensive epidemiological study on psychiatric morbidity in Mexico City. The studied population was aged 18 to 64 ye ars living permanently or temporarily in dwellings of the 16 political divisions of the city. This was a household survey, using a multi-eta pic sample scheme, where at the last stage, only one adult was selecte d from each household, taking care that the final sample included an e qual number of men and women. The specific objectives were: To estimat e current and lifetime prevalence of specific psychiatric disorders in the adult population, aged 18 to 64 years, in Mexico city. To identif y the comorbidity lifetime patterns of the population with psychiatric disorders. To identify the discapacities associated with the differen t psychiatric disorders included in the study and the comorbidity patt erns. To identify and study the help-seeking process or the absence of it in the surveyed population. To explore and determine the strength of the association between psychosocial variables and psychiatric morb idity. The dependent variable is the lifetime and 12-month prevalence of the following psychiatric disorders: agoraphobia, social phobia, sp ecific phobias, panic disorder, generalized anxiety, depressive episod es, dysthymia, manic and hipomanic episodes, obsessive-compulsive diso rder and substance use, abuse and dependence. Collaboration was establ ished with the University of California, at Fresno. The CIDI 1.1 in a modified version, the CIDI-Fresno, was used as the basic instrument. T his version incorporates questions on the DSM-IV diagnostic criteria, in addition to the DSM-III-R and ICD-10 criteria, and extends the scop e to formal and informal service utilization for each disorder. On the other hand, several independent variables were also considered in ord er to explore their relation with psychopathology. For this purpose, o ther questions and scales, most of them already used by Kessler in the National Comorbidity Study (NCS) in the United States, as well as oth er instruments previously used in Mexico, such as the GHQ-12 and the R QC, were incorporated in separate sections to the survey. The complete instrument included 13 sections, six dealing with psychopathology and the other seven related to general and specific situations that could potentially be associated with psychiatric disorders. These include: sociodemographic and general information variables, health problems, a ssessment of children aged 4 to 16 years living with the interviewed a dult, recent and past history of life events, post-traumatic stress, f amily history and observations during the interview. The survey was pe rformed by lay interviewers, all of them trained during a two-week per iod, supervised by clinicians all through out the field-work phase. Th e vast information gathered permits the study of psychopathology and m ental health issues from different points of view, as well as its repl ication in other sites. Also, several lines of research, including cro ss-cultural comparisons, are open for further exploration and developm ent.