In Australia, mental and AOD use disorders are the fourth leading cause of burden of disease (12% of total burden) following cancer (18%), cardiovascular disease (CVD; 14%), and musculoskeletal conditions (13%) [69]. Research conducted on the general population indicates that approximately one in two people will develop a mental disorder at some point in their life [63, 70]. The Australian National Survey of Mental Health and Wellbeing (NSMHWB) conducted in 2007 found that more than 41% of Australian adults (45% of men and 38% of women) had experienced a substance use, anxiety, or mood disorder in their lifetime [63]. The projected lifetime prevalence of these disorders is 28%, 25%, and 23% respectively [71]. Just over 10% of Australian adults had experienced two classes of mental disorders, and just over 4% had experienced three [63].
The 2007 NSMHWB also found that one in five Australian adults (18% of men and 22% of women) had a substance use, anxiety, or mood disorder in the past year, representing close to 3.2 million Australian adults [72]. Approximately 25% of people with mental disorders were found to have two or more classes of mental disorder [73]. The prevalence of single and co-occurring substance use, anxiety, and affective (i.e., mood) disorders among Australian men and women from the NSMHWB is depicted in Figure 4. The overlapping portions of the circles indicate the proportion of the population who have co-occurring disorders. For example, 1.3% of men and 0.8% of women have a substance use and anxiety disorder only.
Recently released preliminary findings from the 2020-21 NSMHWB report comparable estimates of lifetime (44%) and past year (21%) mental disorder. Findings from the 2017-2018 Australian National Health Survey [74] have shown that mental and behavioural conditions continue to affect around one in five Australians (20.1%), making these conditions the most commonly experienced chronic conditions in Australia. Furthermore, comparisons with the previous 2014-2015 survey suggest that both anxiety-related conditions and depression are becoming more prevalent in the Australian community, affecting 13.1% (an increase from 11.2% in 2014-15) and 10.4% (an increase from 8.9% in 2014-2015) of Australians respectively [74]. Despite significant government investment in mental health services, the potential for a shadow pandemic of mental ill health as a consequence of the COVID-19 pandemic remains a concern, particularly among young Australians [75].
Figure 4: Prevalence (%) of single and co-occurring DSM-IV affective, anxiety and substance use disorders amongst Australian males (left) and females (right) in the past year
Source: Teesson et al. [73].