A delusion is a firm and fixed belief based on inadequate grounds not amenable to rational argument or evidence to contrary, not in sync with regional, cultural and educational background. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, or some other misleading effects of perception. Delusions have been found to occur in the context of many pathological states (both general physical and mental) and are of particular diagnostic importance in psychotic disorders including schizophrenia, paraphrenia, manic episodes of bipolar disorder, and psychotic depression.