National survey of Mental Health
The 2007 National Survey of Mental Health and Wellbeing of adults provides information on the 12-month and lifetime prevalence of mental disorders, such as anxiety and depression, in the Australian population aged 16–85 years.
The survey estimated that almost half (45%) of the population in this age range will experience a mental health disorder at some time in their life (about 8.7 million people based on the estimated 2017 population).
It also estimated that 1 in 5 (20%) of the population had experienced a common mental health disorder in the previous 12 months (about 3.9 million people based on the estimated 2017 population).
Of these, Anxiety disorders (such as social phobia) were the most prevalent, afflicting 1 in 7 (14.4%) of the population, followed by Affective disorders (such as depression) (6.2%), and Substance use disorders (such as alcohol dependence) (5.1%). (Australian Institute of Health and Welfare, 2019)