The mental health of Australians 2

7.2 Impact of comorbidity

Page last updated: May 2009

7.2.1 Severity
7.2.2 Days out of role

7.2.1 Severity

There was a strong relationship between the level of comorbidity and severity of mental disorders (Figure 7-3). A greater proportion of people with more than one class of mental disorder experienced severe impairment due to their mental disorders compared to those with only one class of mental disorder. Over half (54.0%) of people with comorbid classes of mental disorder experienced severe levels of impairment, compared to one in twelve (7.5%) of those with only one class of mental disorder.

Figure 7-3: Proportion of people with single and comorbid 12-month mental disorder classes by severity level

This graph is described in section 7.2.1Top of page

7.2.2 Days out of role

Days out of role measures the number of days in the 30 days prior to interview that a person was unable to function in their usual role due to physical or mental health problems. The average days out of role increased with greater comorbidity (Table 7-2). People who did not have a 12-month mental disorder experienced about one and a half days out of role (1.4 days) in the 30 days prior to interview. Of those with only one mental disorder, those with affective disorders reported the highest number of days out of role (4.2 days). Those with affective and anxiety disorders reported the highest days out of role of those people with two disorders (7.6 days). However, people with all three mental disorder classes experienced nearly seven times as many days out of role compared to those without mental disorders (9.2 days compared to 1.4 days).

Table 7-2: Days out of role by comorbidity of 12-month mental disorder classes

Days out of role in previous 30 days (mean)

No mental disorder
One mental disorder
Affective disorder only
Anxiety disorder only
Substance use disorder only
Two or more mental disorders
Affective and anxiety disorders
Affective and substance use disorders
Anxiety and substance use disorders
Affective, anxiety and substance use disorders
Total population