A national sample of school-attending adolescents aged 12-20 years (n = 8435) filled out an anonymous self-administered questionnaire. We considered a group of 868 adolescents with probable psychiatric problems (PPP) in order to identify personal, psychological and environmental factors as well as help-seeking behaviour associated with consultation of mental health professionals (MHP). Among the adolescents with PPP, 13.7% consulted MHP at least once during the year. Logistic regression analysis showed that consultation with MHP was more frequent for adolescents with multiple problems (OR = 2.3), functional physical disorders (OR = 1.9), family problems (OR = 2), separated parents (OR = 4.4) or multiple contacts with other doctors (GP, school doctor and other specialists, OR = 2.2, 3.6 and 2.6, respectively), and among those who confided in teachers or youth group advisors (OR = 2.2). Those who confided in peers consulted MHP less often (OR = 0.5). However, consultation with MHP was not associated with other sociodemographic or educational characteristics, with type of problem (internalized or externalized), or with confiding in one's parents.

A group of 3,287 French school pupils between the age of 12 to 20 years, of whom 14.4% had sought consultation for depression, were investigated in order to analyse the factors related to the type of medical help obtained. Multivariate analyses showed that severe emotional distress alone did not explain the help-seeking behavior. Thus, among those adolescents with the same anxio-depressive level, girls, older adolescents, adolescents with parents living apart, with health worries, and adolescents often absent from school more often sought help for depression. Socio economic status, however, did not correlate with a higher level of consultation for depression. Adolescents attending medical services for depression had a higher consultation rate, for any reason, with general practitioners and with school nurses, in whom they confided more often than their counterparts. Nonmedical professionals also seemed to contribute to accessing to medical help for depression. Overall, those who consulted for depression, in very limited numbers turned to mental health services (8.4%).

In cross-sectional studies, misclassifications of exposure and of health status may be related. For instance some subjects may tend to overreport both exposure and disease. A misclassification is said to be nondifferential if the sensitivity and the specificity which characterize it do not depend on the true status of the subjects for the other variables. Nondifferential misclassifications of two dichotomic variables may be correlated if the probability of being misclassified for one of them depends on the presence of an error of classification for the second one. Models are presented to estimate the bias induced by correlated nondifferential misclassifications on an odds ratio whose true value is unity. For most usual situations, when the great majority of the subjects are healthy and nonexposed, the influence of overreporting is shown to be larger than that of underreporting. It appears to be relatively easy to find a spurious, but significant, relationship. Real data are analysed to show that the potential consequences of correlated nondifferential misclassifications are not purely theoretical. In a sample of 1676 subjects from the general population we observed significant relations between left-hand shift and various aspects of health status: reporting a history of eczema, experience of a serious health problem in the past, experience of a serious health problem presently, use during the last month of analgesics or of drugs for circulatory problems, or digestion, consultation with a physiotherapist or hospitalization during the last year. These results, as with many similar ones previously reported, are highly suggestive of an information bias. They are less easily explained by biological hypotheses, e.g. Geschwind's theory of cerebral lateralization, than by correlated misclassifications resulting from overreporting of both the use of the left hand and the existence of some health problems by healthy right-handers. The modelling used in this report supports this hypothesis.

A group of 3,287 French school pupils between the age of 12 to 20 years, of whom 14.4% had sought consultation for depression, were investigated in order to analyse the factors related to the type of medical help obtained. Multivariate analyses showed that severe emotional distress alone did not explain the help-seeking behavior. Thus, among those adolescents with the same anxio-depressive level, girls, older adolescents, adolescents with parents living apart, with health worries, and adolescents often absent from school more often sought help for depression. Socio economic status, however, did not correlate with a higher level of consultation for depression. Adolescents attending medical services for depression had a higher consultation rate, for any reason, with general practitioners and with school nurses, in whom they confided more often than their counterparts. Nonmedical professionals also seemed to contribute to accessing to medical help for depression. Overall, those who consulted for depression, in very limited numbers turned to mental health services (8.4%).