To what extent does having the genes impact on behaviour and intellectual function Use schizophrenia or
Human behaviour and intellectual function results from a complex interaction between genetics and environment. Our sex, skin colour and to some extent our temperament and intellectual capacities are determined by our genetic makeup (Reber & Reber, 2001). Biological predispositions interact with the environment to determine an individual’s characteristics and behaviour. Clear biomedical evidence exists for the heritability of physical characteristics yet it is less clear to what degree psychological characteristics such as intellectual ability, emotionality and temperament are genetically transmitted. The limits hereditary places on an individuals potential and the extent to which an individual may be genetically predisposed to develop a certain psychopathology is largely speculative. The relative contributions of nature and nurture to an individual’s behaviour and intellectual function have long been disputed, although an accumulation of evidence points to a genetic basis for psychopathologies such as schizophrenia and Down syndrome. This essay will consider the genetic basis of schizophrenia. ... The aetiology of schizophrenia will be explored in terms of biochemical, neurophysiological and familial evidence. The essay will focus primarily on how genetics contribute to an individual’s behaviour and intellectual function in the case of schizophrenia. ... The biological and genetic evidence for abnormalities such as schizophrenia will be evaluated. It will be argued that schizophrenia is a polygenic disorder. It is likely that a number of different cerebral structures are implicated as inducted from the specific symptoms and type of schizophrenia an individual manifests. Schizophrenia is one of the most prevalent yet misunderstood psychotic illnesses affecting an estimated 1% of the population (Dohrenwend & Dohrenwend, 1974, cited in Rosenhan & Seligman, 1995). This debilitating condition which affects both men and women is manifest in their behaviour, cognitions, and emotions. ... Schizophrenia is the most common psychotic illness and comes in a number of different guises to include paranoid, catatonic, disorganized, residual and undifferentiated schizophrenia (Rosenhan & Seligman, 1995). ... The symptoms of schizophrenia tend to occur in a certain chronology which is dependent on the type of schizophrenia and the gender of the sufferer (Nolet, 2002). The course of illness has a certain amount of predictability which suggests a biological regulatory mechanism may control the symptoms of schizophrenia and the timing of onset. The first schizophrenic episode typically occurs from late teens to mid adulthood although schizophrenia in men tends to onset earlier than schizophrenia in women. ... Other diagnostic criterion included in the DSM-IV are disorganized speech, catatonic or disorganized behaviour and negative emotional affect (Rosenhan & Seligman, 1995). If a diagnosis of schizophrenia is to be arrived at the symptoms must have persisted for at least 6 months and caused a noticeable deterioration in the person’s emotional, social and occupational functioning (Rosenhan & Seligman, 1995). ... Type 1 or acute schizophrenia is characterized by positive symptoms such as hallucinations and delusions, whereas type 2 or chronic schizophrenias are characterized by negative symptoms such as withdrawal and apathy.