The burden of psychiatric disorders in the developed countries has been identified by the screening questionnaires and standard clinical interviews at a high level, but the epidemiological studies of psychiatric disorders in our country are brief and their numbers are few. Planning for providing essential mental health services to the people requires us to be knowledgeable about the
   present status of psychiatric disorders in the society. The objective of this research was to carry out the epidemiological study of the psychiatric disorders in the individuals 18 years and above in urban and rural areas of Hamadan province.

664 individuals selected through randomized clustered and systematic sampling methods among the existing families of Hamadan province and the Schedule for Affective Disorders and Schizophrenia (SADS) questionnaires completed by the clinical psychologist. The diagnosis of the disorders was based on DSM-IV classification criteria.

The results of the study showed that the overall prevalence of psychiatric disorders in the province was 11.28% (17.2% in women , 5.8% in men). The anxiety and mood disorders with 5.87 and 2.71% respectively had the highest prevalence in the province. The prevalence of psychotic disorders in this study was 0.60% , neuro-cognitive disorders 1.35% and dissociative disorders 0.75%. In the group of mood disorders, major depression with 2.56% and in the group of anxiety disorders, phobia with 2.56% had the higher prevalence.

This study showed that 8.13% of studied individuals suffered from at least one of the psychiatric disorders. The prevalence of psychiatric disorders in the province among the individuals in the age group of 66 years and above was 13.33%, individuals whose spouses had passed away 18.75%, urban residents of province 9.81%, illiterate individuals 12.80% and housewife individuals 12.31% was more than other individuals in the sample.

Being aware of this matter reveals the responsibility of the health policy makers and programmers in prevention, treatment and medical education more than before , in relation to preparing application and executive plans in Hamadan province for mental health.