Conceptualization and measurement of insight.

Insight is a complex phenomenon which has been conceptualized variously as a symptom of schizophrenia and as awareness of illness, making comparisons of studies measuring insight difficult. Furthermore, attempts to establish a correlation between insight and successful treatment outcomes are fraught with methodological problems. Specifically, categorical judgments fail to capture important information about the quality of insight; inappropriate inferential statistics have been used; and validity of instruments to measure insight has not been established. In future research, the concept of insight needs to be clarified. Nonparametric statistical analysis should be considered for small, nonnormally distributed samples. Qualitative exploratory research is needed.