The authors describe the relationship between the major depressive disorder and somatization. A literature review documenting the incidence and prevalence of depression in primary care and the rate of misdiagnosis is presented. Evidence is collated that points to several factors in misdiagnosis. The patient often selectively complains about the somatic manifestations of depression, minimizes the affective and cognitive components and is treated symptomatically. This is due to the physician's lack of recognition that the patient may have major depressive disorder and yet not recognize and report the mood component. The authors develop a conceptual; model that elucidates the mechanism behind the selective perception and focus by the patient on the somatic manifestations of depression. In this first part, the influence of sociocultural and childhood experience on the ability of the patients to recognize and report mood changes is delineated. Understanding this model is crucial in preventing misdiagnosis and potential iatrogenic harm to the patient.