Psychiatry and Neuroscience Update by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9783319953601
Publisher: Springer International Publishing

Social isolation contributes to an inadequate or complete lack of social support, which is to be considered as an important vulnerability factor as regards depression.

Other aspects concerning construct validity are related to the correct use of the terms, the concepts, and their paradigms, that is, whether the behavioral aspects of a model are properly explained according to a certain paradigm [3]. That is the case of the learned helplessness paradigm, the behavioral despair paradigm, and the chronic mild stress-sucrose preference-anhedonia paradigm. Observations regarding each one of these particular constructs will be mentioned in the following description of the current animal models of depression.

In general, some authors appreciate this validation criterion as the most important to be assessed in evaluating a model, while others assume that the validation of a model cannot entirely rely on the construct criterion because of the constant changes in scientific theories and in the conventional classification references that indicate what should be measured [3]. Despite these divergent attitudes, it is evident that the process of construct validity positively contributes to the development and refinement of any model of depression [3].

According to Belzung and Lemoine, the criterion of homological validity encompasses two subcategories: species validity and strain validity. The first criterion refers to the challenges in selecting a particular species for an animal model, depending on the cognitive or biological mechanisms to be studied. On the other hand, strain validity specifically refers to strain differences, that is to say, the anatomical, physiological, or behavioral differences that result from genetic changes within a species [2].

Following the new approach, the criterion of pathogenic validity refers to two contrasting dimensions: ontopathogenic validity and triggering validity . In the first case, the criterion refers to early factors in the environment which interact with an initial organism turning it into a vulnerable organism (a predisposed organism), following the theory of diathesis. On the other hand, a model meets triggering validity when there is similarity of triggering factors during adulthood, which produce a pathological organism after interacting with a vulnerable or a non-vulnerable initial organism. It is paramount to take into consideration that etiological factors are not required to be materially identical but semantically similar instead. This means that the stimuli applied can be of different nature as long as they have the same meaning or effect (semantical similarity) in the animal model and in humans as well [2].

Although the Belzung-Lemoine’s concept of species validity is not directly mentioned in Willner’s publications, it coincides with the classical notion of homological validity. Strain validity, as well as ontopathogenic and triggering validity, on the other hand, might be integrated in Willner’s conception of construct validity (even when they could refer to different constructs), due to their agreement on the relevance of the genetic predisposition in the etiology of the disease both in animals and humans.

Mechanistic validity refers to the similarity between the mechanism – either cognitive or neurobiological – which is supposed or known to underlie animal disease and the mechanism supposed to be working in human disease [2].

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