A two-stage mental illness survey of a random sample of persons aged 17 years and over from a rural community in Cantabria, Spain, is described. In the first stage newly qualified doctors and final year medical students interviewed 1223 respondents (583 males and 640 females) at their homes, using the General Health Questionnaire (GHQ-60) and other psychopathological and social questionnaires. In the second stage senior psychiatrists carried out an at-home interview on a sample composed of all those who in the first stage scored above the cut-off point on the GHQ, and of a similar number of persons selected at random from two independent batches of below-threshold scorers on the GHQ. Because of this design the prevalence figures have to be weighted in order to represent the whole first stage sample.
Of the total population, 14·7% (8·1% of the men and 20·6% of the women) had psychiatric disorders as defined by the PSE-ID system. In males depression accounted for about twice as many cases as anxiety states, but in females there was a predominance of a combination of anxiety, phobic and obsessive conditions. Men presented a higher prevalence of disorders over the age of 35, with a peak around the age of forty, while in women the rise of prevalence was over the age of 45. There was, however, no significant association with marital status.
Unemployment was related to mental illness in males but not in females, while the reverse was true of the type of work. In both sexes the presence of children under fourteen in the household was not related to a rise in prevalence. Women exhibited a high rate of mental illness in the low educational level and in the low social and religious integration groups, but in men a rise in prevalence was found in the low social status, low educational level and low social integration groups. Lastly, in both sexes the presence of physical illness was related to mental disorders.