Psychiatric comorbidity: concepts, controversies and alternatives.

OBJECTIVE

To review various concepts of psychiatric comorbidity, their implications, surrounding controversies and underlying issues. A further aim is to propose an alternative term that might be more clinically useful and meaningful for describing the coexistence of mental disorders.

CONCLUSIONS

There is wide dissatisfaction with the concepts of psychiatric comorbidity because of different meanings, speculations on which they are often based and consequent confusion. Although the coexistence of mental disorders should be studied further so that any patterns in the corresponding relationships can be elucidated, there is a need for conceptual clarity and making the concept more meaningful for clinical practice and treatment. With that in mind, this present paper proposes avoidance of the term comorbidity and introduction of the term 'co-occurrence'. The latter is defined in this article, and the distinction made between diagnostic co-occurrence and clinically significant co-occurrence.