Schizophrenia is a serious, complex mental disorder with a chronic and heterogeneous course. It is estimated that more than 21 million people worldwide are diagnosed with schizophrenia. Evidence suggests that schizophrenia is probably not related to a single biological factor, but to an interaction of different pathological mechanisms, including intrinsic and extrinsic risk factors. Patients have three major symptom dimensions, which can be described as positive symptoms (hallucinations and delusions), negative symptoms (affective flattening, alogia, and avolition), and cognitive symptoms (perception, memory, and attention).
