Schizophrenia, as a mental disorder, has many different explanations. Because of this, it is necessary to evaluate it based on different psychological concepts. An individual difference is the concept that all individuals respond to mental disorders in different ways. This implies that all individuals have different reactions to treatments, different symptoms, models, etc. For example, in evaluating the DSM, which is used to diagnose schizophrenia, it is implied that all those with the mental disorder must have at least six of the symptoms mentioned for a minimum period of time. This does not qualify for all patients, thus it can be assumed that individual differences play a part in determining a mental disorder. Another example for individual differences is the reaction to the different treatments used to treat schizophrenia. Some benefit from atypical, while others benefit from typical. This shows that all reactions to medicine are dependent on individual differences. An advantage of taking into consideration individual differences is that all diagnosis can be made with specific features that relate to the individual. This can change their relapse rate, daily life occurrences, etc. A disadvantage, however, would be that not all differences can always accounted for, as that would begin to become reductionist.
Another evaluative point is the discussion of free will vs determinism. Free will takes into consideration an individual's ability to change his/her disorder, or for them to bring it about into their daily lives. The cognitive model and behavioral model often support free will, because they assume that factors in the individuals life have led to this mental disorder. For example, in the cognitive model, schizophrenia is caused by faulty cognitions, perceptions, and language. These are assumed to be adjustable, and therefore assume that free will is involved. An advantage of free will is that it is assumed that a disorder can be fixed or changed by belief or willingness to change.