Biblioteca Virtual en Salud

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Abstract Depression is a main Public Health problem due to its high prevalence and to the costs for intervention and treatment. Therefore, it is necessary to identify strategies that allow an adequate assessment that would let us obtain a more precise and useful diagnosis. Nevertheless, animportant obstacle for this task, is a lack of theoretical clarity in regard to diagnostic criteria or, especially, to symptoms which are relevant for depression. This fact is obvious in the scales focused on depression assessment, which have a broad variety of symptoms to assess, and it is possible to overestimate some areas or to underestimate others, related to theoretical criterions which were involved in test construction. So, depression is evaluated in accordance with the questionnaire that is used and, of course, depending of theoretical framework that supports this tool. Therefore, depression is defined in line with the criteria which evaluates it, with regard to assessment s criteria, which could explain the usual difficulty to identify common symptoms when some tools are used, which are then identified as genuine symptoms of depression. As the aim of this paper is to improve some of this limitations, the State/Trait Depression Questionnaire (ST/DEP) is showed as an useful tool for clinical and research work. It offers an assessment of one of the component of depression, the affective one, providing two

measures:

State and Trait. This allows to differentiate between intensity and frequency. Main-axis factor analysis has been made and the results have shown two main factors in affectivity Dysthymia (negative affection) and Euthymia (positive affection). The interest on positive affection assessment aims to obtain a more precise tool. So, when scores are inverted in positive items, it is possible to obtain a measurement of low levels on affectation. The relevance of this fact is emphasized because it has been neglected in most of depression scales, that only identify presence or absence, a fact that limits the ability to estimate slight modifications. This issue is very useful at two levels clinic and research. At a clinical level because it permits to identify slight changes in affectation, which could be important as measurement oftherapeutic efficacyand ofsymptoms remission. In research, because it offers the possibility to dispose of one able tool to differenciate of low levels of affectation, which allow a more accurate estimation of the depression symptoms, specially when working with a nonclinical population. The present study was carried out with a sample of 300 participants (103 males and 197 females), with mean age of 21.82 (2.74 s.d.) for males and 22.26 (3.66 s.d.) for females. It was an instrumental study where the Spanish Experimental Version of Stat-Trait Depression (ST/DEP) was used. All participants received information about research and they answered the questionnaires voluntarily. The findings are shown separately for the two scales (State and Trait) and for the two sub-scales (Dysthymia and Euthymia). Data indicated significant differences between males and females, being the highest scores for females. This is an evidence related to the higher prevalence of depression in women. It is very important to remark that essentially the same strong state and trait factors were found for both males and females, according to the factor structure of the Spanish Experimental Version of the State-Trait Depression Questionnaire (ST/DEP). These factors explained the 54% variance for females and of 53% for males. The Promax Rotation differentiated two factors clearly Dysthimia and Euthymia. That was similar to what was found in the original English form of the ST-DEP. The factorial structure was then confirmed, because of the bifactorial structure which differentiated the negative and positive affectivity of Depression. Another positive result was the test ability to detect slight changes on affectivity, which will be useful to differentiate between clinical and non clinical population. It is important to point out that the ST/DEP is a measurement of one component of depression affectivity, which has been identified as a relevant component in this disorder, but this tool is not enough to diagnose depression. This fact is relevant, because some tools for depression assessment are used as a diagnostic criteria, a fact that increases confusion in making a differential diagnostic between anxiety and depression or some other symptoms and clinical problems. All this results provide evidences of the psychometric properties of the Spanish ST-DEP, and make this scale a fruitful and useful assessment instrument.