Comorbidity and treatment planning: summary and future directions.

This summary blends the commentaries from the 6 articles in the special section on comorbidity. Included is a discussion of various definitions of comorbidity, the merits and demerits of a hierarchical diagnostic system, and consideration of the extent, patterning, and nature of comorbidity. Directive comments with reference to future intervention planning mention both assessment (distinguishing overlapping constructs) and treatment (sequencing and treatment manuals) issues.