The use of insight scales facilitates the systematic study of ways in which insight covaries with other behaviours and characteristics. Examples:
- There is only a weak correlation between lack of insight and severity of psychopathology.
- Insight rates are lower among detained than informal patients.
- Insight is associated with treatment adherence, but this relationship decreases over time.
Quantitative studies have demonstrated a strong correlation between insight and capacity. However care must be exercised in applying this finding in legal contexts. The studies that have demonstrated this correlation quantify capacity using the MacArthur Competence Assessment Tool for Treatment Decisions (MacCAT-T), which differs from capacity as defined in the Mental Capacity Act. The MacCAT-T includes a dimension (‘appreciation’) that has a partial conceptual overlap with the concept of insight.