The eating disorder evolves in a complex manner stemming from an individual's own unique biology, his/her innate personality, and life experiences.
There are three reasons for which eating disorder has received little attention and considerable uncertainty. Firstly, there are inherent difficulties in measuring the subjective strength of hunger or appetite. Secondly, ratings of hunger are likely to be unreliable in people who have complex and distorting ideas about what they should be eating. This refers to psychological disorder. The sufferer may mislead others, and perhaps even herself, when putting her subjective experiences into words or in terms of a rating scale. On the other hand, for obvious reasons, what an eating-disordered individual actually eats cannot be taken as a simple behavioural indicator of the drive to eat. Lastly, clinicians and other experts may assume that they know about hunger and the like in eating-disordered subjects.
Hunger or the drive to eat might be abnormal in being reduced or increased but the dilemma is that the diagnosis of any eating disorder is never considered. For instance, weight loss along with the physical illness with loss of appetite or depressive illness is not appropriately described as AN. The 'nervosa' implies that the relationship between the person's eating and their weight loss is more complex, more entangled with wider personal issues than that of being simply 'off their food'. Even those who would claim that AN sufferers do possess a diminished appetite may want to reserve the diagnosis for those people who seem to be not eating for broadly 'psychological' reasons and who have relevant and related ideas often about weight concern. For instance, a sufferer may couch her immediate aversion to eating in terms of bloating or discomfort, but also have wider ideas of guilt or whatever. At the extreme, it is certainly conceivable that a person could present at low weight that was without both 'weight concern' and motivated eating restraint and who seemed to have true anorexia.
Factors - Biological, Social and Psychological
Although patients with AN look and behave very much alike once their starvation is well advanced, there is no single cause. However research reveals that all causes emerge from a single psychological disorder of 'Depression'. Now, it varies and depends according to the antecedents of the illness, how one considers it. The interaction model suggests that three factors lead to the emergence of AN -biological, psychological, and social. Usually it starts with inappropriate dieting at the time of pubertal changes, when girls are rapidly gaining body fat. Each of these three factors has a greater or lesser impact on particular individuals in which AN develops. Some girls have a strong innate tendency to develop the disorder, but the genetic predisposition must be necessary for the disorder to occur. In most individuals AN (genetically) never develops, even though they are exposed to the same ecological burdens and social pressures that influence persons. Many environmental influences reinforce the vulnerability to the disorder that lead to dieting. Certain parent-children relationships are more conducive to the development of the disorder, but in and of themselves they do not cause it. Overemphasis on all aspects of eating, excessive concern by the patient about