Deconstructing current comorbidity: data from the Australian National Survey of Mental Health and Well-Being

Background Comorbidity in epidemiological surveys of mental disorders is common and of uncertain importance. Aims To explore the correlates of current comorbidity. Method Data from the Australian National Survey of Mental Health and Well-Being were used to evaluate the relationships between comorbidity, disability and service utilisation associated with particular mental disorders. Results The number of current comorbid disorders predicted disability, distress, neuroticism score and service utilisation. Comorbidity is more frequent than expected, which might be due to the effect of one disorder on the symptom level of another, or to the action of common causes on both. The combination of affective and anxiety disorders was more predictive of disability and service utilisation than any other two or three group combinations. When people nominated their principal disorder as the set of symptoms that troubled them the most, the affective and anxiety disorders together were associated with four-fifths of the disability and service utilisation. Conclusions To make clinical interventions more practical, current comorbidity is best reduced to a principal disorder and subsidiary disorders. Declaration of interest None. Funding detailed in Acknowledgements.