Involve both genetic and environmental factors to build monkey models of mental disorders

Mental diseases, such as schizophrenia, are typically the result of multiple abnormalities, including neurobiological, psychological and sociological processes, particularly the environmental and genetic disorders (Bailey, 2000). Consequently, in psychic medicine, animal models should be developed via methods consistent with their associated theories of mental disorders. However, many conventional models are constructed via genetic manipulations or surgical operations to the nervous system (Bezard, 2006, van der Staay, 2006, 2009), e.g. administrate animals with agonists or antagonists of various neurotransmitters or drugs to reproduce human mental disorders. The usage of these methods, which should be considered as simple neuro-pharmacological interventions (Duan et al, 2013, van der Staay, 2009; Zugno et al, 2014,), only a limited number of clinical symptoms can be simulated. Moreover, several critical environmental and genetic factors can be easily overlooked. A famous study on a set of identical female quadruplets who all developed schizophrenia between the ages of 20−24 demonstrated the critical roles that genetic backgrounds play in this disease (Mirsky et al, 2000). However, heredity is not able to explain all the cases of schizophrenia. Some 60% of schizophrenia patients have no close relatives with the illness, suggesting that a variety of other factors aside from genetic background play important roles in schizophrenia, especially individuals with an existing genetic predisposition. Given the complex poly-genic nature of schizophrenia and the multitude of other risk-factors, an ideal animal model of the disease requires screening individuals with similar genetic predisposition under similar environmental conditions that humans experience. To do so requires large populations that provide adequate samples. In southern China, there are numerous monkey breeding centers with populations ranging from the thousands to tens of thousands. Recently, we conducted a screening at the primate center of Jin Gang Biotech International in Haikou, Hainan Province, China. This center breeds more than 20 000 cynomolgus monkeys (Maca fascicularis) in different colonies (Table 1). 1