Write 6 pages thesis on the topic drugs hormones and the brain. The model must be broken down into observables or assigned qualitative or quantitative attributes or measurable elements that can be tested (Belzung & Lemoine, 2011). In determining the validity of the animal model, the most important criteria are the reliability and predictive validity of the model system that are relevant to the independent and dependent measures. Henn, Edwards & Muneyyirci (1993) points out that the independent variables include the construct, etiological and face validity (p 150). Emilien, G. (2002) offers an additional criterion that is relevant for the dependent variable includes the convergent and face validity of the variable. All the animal models used in understanding psychiatric disorders mimic psychiatric syndrome through establishing homology between animal behaviour and disorder to be modelled. The signs and symptoms associated with the particular psychiatric disorder are enumerated and ability of experimental manipulation in order to induce homologous changes in test animal behaviour is determined (Emilien, 2002). The animal models consist of the independent variable and dependent measures that will assess the effects of manipulation to induce the abnormality. Predictive validity and reliability are necessary and sufficient criteria for justifying the use of such models in conducting scientific research in psychiatric disorders.

Reliability refers to the stability and consistency with which the variables are observed while face validity independent variables refers to the phenomenological similarity between the behaviour of the animal model and specific symptoms of the human disease or disorder. The consistency of the independent variable is measured by the ability to manipulate the independent variable with high precision and reproducibility of the phenomenon under similar conditions since this is critical in any scientific study (Emilien, 2002). The validity of the animal model in studying psychiatric disorder is another criteria that should be met and there are several types of validity that include predictive, convergent, discriminative, etiological and face validity. The purpose of the model is to enhance understanding of psychiatric disorders in human population and only valid scientific observables are the correlations thus the model must lead to accurate prediction (Menard & Treit, 1999, p 593).