Comparison of small area techniques for estimating prevalence of mental disorder symptoms among Iranian's southern adolescents.
BACKGROUND
Mental disorders may lead to several complications in adolescents' people whose compensation is very difficult and sometime impossible. They are prone to emotional problems. Therefore, knowing prevalence of diseases and valid statistical technique is necessary to plan for prevention and control of diseases.


METHODS
In this cross-sectional study; direct, synthetic, and post-stratified estimation as small area methods were used to compute mental disorder symptoms (MDS) prevalence with county-level reference among adolescents in south of Iran. We conducted Mental Health Study data (MHS) conducted in Bushehr Province, southern Iran in 2005 for individual-level classification of MDS (n=2584). Students were in grade 9, 10 and 11, and enrolled with complete satisfaction.


RESULTS
The synthetic method was superior to the direct and post-stratified technique with respect to discrepancy statistics such as MSE and width 95% confidence interval (MSEs(synthetic)≈0.001, MSEs(post-stratified)≈0.010, MSEs(direct)≈0.100). In addition, the width range of 95% confidence intervals for all county estimates was 9.7% to 65.3% based on in direct methods. Besides, the width range of 95% confidence intervals for all county estimates under post-stratified and synthetic method was 16.7% to 62.2% and 11.8 %-25.1%, respectively. Hence, we could categorize prevalence of mental disorder symptoms in Bushehr's counties into five categories based-on synthetic methods. Maximum and minimum prevalence belongs to Geneveh (0.403) and Dashty (0.398) counties, respectively.


CONCLUSIONS
The MHS cannot be used as a valid source of county-level mental health prevalence data and the small-area method such synthetic method should be used to estimate prevalence of mental disorder symptoms in county-level. Furthermore, the synthetic method improved MDS prevalence more than direct and post-stratified methods.