Depression is one of the most common psychiatric diseases and has extensive socio-economic impacts. One of the ICD-10-criteria for the diagnosis of depression is cognitive deficit. The aim of this study was to examine these deficits through new methods to get more basic knowledge about this disease. In literature these cognitive deficits are discussed controversial. A number of studies show deficits in neuropsychological tests. Notably in several studies could be found that the transformation of auditory processing shows coherence with the level of serotonin in blood, as well as a correlation in principle with the existence of depression. Another aspect is the content of thoughts, in special the negative automatic thoughts concerning oneself and the environment. Concerning this subject there are far less studies, but there are indications that depressive patients suffer less of objective cognitive deficits but of a biased self-perception. This study deals first part with the impairment of auditory processing. Three auditory tests concerning discrimination, choice-reaction and selective attention were performed as well as a measurement of reaction-time during these tests. For exploring the contents of thought on the other hand, processes of categorisation on a pre-semantic level were tested. Here the participants had to appraise Chinese characters in seven categories. Furthermore some aspects of self- and social-perception were investigated with psychometric tests. 22 depressive in-patients of the clinic for psychiatry and psychotherapy in the University Hospital Aachen and 22 healthy persons of the control group attended this study. The results show that the depressive patients only had a light worse performance in the auditory tests, which reached no statistical significance. Concerning the categories of the Chinese-Test, we only found a general trend for a worse appraisal of the Chinese characters. Only in the category “beautiful-ugly” there was a statistical tendency for a worse appraisal. The results of the psychometric tests show that the depressive patients had a significant worth self-perception and more self-doubts; however the social attitude was not affected. Besides a tendency to hypochondria was proofed. An interpretation of these results is that depressive people have not so much problems with cognitive processing but with biased contents of thoughts. It was also shown that the depression does not affect all contents of thoughts equally: Especially the self-perception and the physical perception are affected but not ethical aspects. There are some deficits in the study design so that the results should be discussed critically. The medication of the patients was not considered as well the large rage of age. Also in the matching of the two groups not all possible influencing factors were take into account
