In a mental-health context insight can be defined as being aware that you have a mental-health problem; being aware that you need treatment and being aware that your symptoms are due to an illness. A team of Spanish researchers studied insight in a study of 110 patients with psychosis. They found that after two years of illness insight was poorer in people suffering from schizophrenia than in people suffering from other types of psychosis. The more severe people's psychosis the less insight they had. Being depressed when one develops psychosis; having poorer decision-making skills and a lower IQ, and going for a longer time without getting help were all associated with poorer insight as were reductions in frontal and parietal grey matter.
Parellada, Mara ... [et al] - Trait and state attributes of insight in first episodes of early-onset schizophrenia and other psychoses: a two-year longitudinal study Schizophrenia Bulletin 37 (1), 38–51, 2011