In diagnostics of the depression psychiatrist has a lack of an objective knowledge about patient state. Except for very strong depressions no significant changes of the physiological parameters are measurable. Almost all information about patient mental state is obtained in verbal form on the basis of conversation with the patient. Due to this fact data are vague, uncertain, inconsistent and also indeterminable. The most popular modern approach to the etiopathogenesis of a depression is based on cognitive-behavioral theory of depression. This theory assumes that "the depression is caused by incorrect cognitive processing of information coming from an environment". Description of this problem and use of FCM is given by Vysoky [133] and we have dealt with it in an earlier section. We feel that use of NCM in the place of FCM will yield better results. This task of working with NCM to study medical diagnostics is left for the interested reader as a lot of indeterminacy is involved: for instance it is well known that certain types of food may trigger depression, meeting some people can cause depression, and several times mood-swings are connected with changes in the weather. Above all, gender, age, social status and the type of (other) diseases may also be factors, which help us to understand depression.
