Introduction

A debilitating disorder that occurs approximately 0.5 to 1% within any given population. Complex genetic, environmental and psychological etiologies come under the pathophysiology of schizophrenia. A multi-factorial sickness ‘Schizophrenia’ is described by a genetic factor (great hereditary) and biological threat issues including societal pressure and cannabis habit. It is caused by the mutual act of various genes that have minor result and various environmental factors due to which mental disorder developed. It is considered as ‘Two-Hit Hypothesis’ of schizophrenia that assumes that both inherited and ecological threat issues aggressively because of the advancement of the sickness. Genetic interacts with the environment when the expression of one’s genetic tendency depends on the environment in which he/she is living or the effects of environment on a trait are differed according to the genome of an individual.

Nowadays, mental disorders are recognized as a disease that affects human populations around the world. In most common and important disorders, hereditary features play an essential part. The most severe psychiatric disorders of adults are functional psychoses that are separated into two chief analytic groups: schizophrenia and bipolar disorder. Schizophrenia is a syndrome that occurs equally in male and female at risk 1%. Schizophrenia is characterized by psychotic features like delusions and hallucinations.

Genetic epidemiology of Schizophrenia

A group of pathologies from which schizophrenia belongs is called as multifaceted hereditary illnesses. It means many genes are involved in each disorder with each gene that has a small effect on the phenotype. The mechanisms of genetic in the production of schizophrenia have been explained by many theories. One hypothesis in which schizophrenia has a standardized pathogenic genotype with pleiotropic influences. Example of pleiotropy is Marfan’s syndrome that is a connective tissue ailment with 12 recognizable abnormalities. 88% of patients are affected by the most common of this disorder and only 12% of patients have the least common disorder. A variety of symptoms may be present in an individual with schizophrenia. The great numbers of evidence show that most of the matters involving schizophrenia are caused by a common gene. Particularly, single gene models are not able to define the ancestral arrangements of sickness precisely. Families or twins; multiple factor polygenic representations can explain such data in the better way.

Genetic Transmission Model for Schizophrenia

It is well recognized that the insanity and such other human diseases and features move from generation to generation. Some authors/ researchers described that schizophrenia is inherited characteristic because of the family combination of the illness or its slighter alternatives. The schizophrenic monogenic model was very attractive because of the various reasons such as plainness, a faith of determining a conforming, meek pathophysiological contrivance and fit into theoretic possibilities like dominant, recessive and with fluctuating penetrance. But it is not followed now these days because it does not fit adequately into the observed data and the idea of one specific gene or few specific genes required for etiological not satisfactory for the development of schizophrenia. For example in 1962, Meehl used monogenic necessary gene in which polygenic factors were used to modify the action. Holzman in 1989 gave latent trait model in which dominant gene as a concealed attribute, a hypothesized neural discrepancy with hypothetically pleiotropic expressions like as schizotypy, eye-movement disorder or schizophrenia. Then, Risch and Bardon in 1984 discussed an assorted ideal in which a particular gene in the blend with some oligogenes and the genetic substrate is formed with the polygenic multifactorial background. All these representations have been applied to suit the environment that have a erratic ratio of achievement to the accessible epidemiological statistics of schizophrenia.