Identifying risk factors
There is no single factor that will guarantee a person does, or does not, experience alcohol or other drug dependence as well as another mental health condition.
Rather, it is the result of a combination of highly personal and complex experiences that people with a dual diagnosis are more likely to be experiencing, such as unstable housing, experience of trauma, and poverty.1, 10
Common factors which may lead to a person experiencing an AOD use disorder and a mental health condition can include:
- genetic factors
- personality
- biology
- social and environmental characteristics.1, 10

Personal and family circumstances can impact a person’s development10, such as parental illness, unemployment, conflict or absence, and abuse or neglect.
As a person reaches adolescence and adulthood, other factors also contribute to health and wellbeing outcomes, such as:
- educational attainment
- the strength of the economy and opportunities for employment
- age and the experience of ageism
- the accessibility of family planning
- interpersonal relationships (such as experiencing family violence).10
The social determinants of health have a complex and dynamic relationship with the development of AOD and mental health needs.
For many, AOD use is a way of coping with ‘psychosocial dislocation’, which occurs when people live without a clear role or purpose in a stable, established community.
Psychosocial dislocation is a common experience of people who are subjected to dispossession, stigma, unemployment, physical or emotional abuse, neglect or mental illness.11
While people who grow up in, or who are exposed to, difficult circumstances are not destined to use substances or develop a dependency, some people are more vulnerable including:
- people who are emotionally distressed, disengaged and disconnected from society through lack of employment or mental health problems
- people who grow up with, or live with, drug use within their family or peer settings
- young people who are disengaged from the school system – children with learning difficulties, or from families experiencing trauma or disadvantage.
Populations that are at greatest risk of experiencing co-occurring mental health and alcohol or other drug issues include:
- young people12
- Aboriginal and Torres Strait Islander people13
- lesbian, gay, bisexual, queer, transgender and intersex people.14
Identifying and assessing the risk - and protective factors - that contribute to an AOD use disorder, mental health condition, or both, is fundamental to determine appropriate interventions and treatment.
Learn more about the social determinants of mental health.
Other complex needs
Each person’s experience of dual diagnosis is different. This can create a complex profile for treatment.1
People with a dual diagnosis or co-occurring disorders are more likely to:
- experience poorer overall physical health
- live in insecure housing
- experience homelessness
- be the victim of violence
- experience poverty or limited income
- have issues with debt
- be in contact with the criminal justice system
- experience family issues, including isolation from their family
- be at risk of self-harm, including suicide
- need social, financial or legal support.1, 3, 7
In recent years, increasing evidence of the impact of co-occurring poor health, has highlighted the role that the increasing risk of substance use and mental health plays in contributing to physical disability and poorer outcomes.15-17
People with AOD issues, mental health conditions, or a dual diagnosis have a higher risk of cardiovascular disease17and may also have heavier rates of:
- alcohol consumption16
- diabetes18
- poor diet19
- physical inactivity20
- obesity19.
Tobacco use tends to be higher among people who have a mental health condition, people who use drugs including cannabis and alcohol, and people who are experiencing a dependence on alcohol or other drugs.21
Tobacco use is linked to a range of other illnesses, such as cancers and dental diseases, that can contribute to the cumulative harms a person may experience.21 Tobacco use can also cost an individual several thousands of dollars a year, depending on how frequently they smoke.
The often complex profile of a person with dual diagnosis/comorbidity can be further compounded by stigma and its impact in reducing help seeking.3, 8
Additionally, the symptoms of a mental health condition itself can be a barrier to treatment.3
For example, if a person is experiencing depressive symptoms of persistently low mood, a lack of energy, and feelings of hopelessness, this can be a barrier to them seeking any kind of treatment.
Related content
- Marel C, Mills K, Kingston R, Gournay K, Deady M, Kay-Lambkin F, et al. Guidelines on the management of co-occurring alcohol and other drug and mental health conditions in alcohol and other drug treatment settings. Sydney: Centre of Research Excellence in Mental Health and Substance Use, Centre NDaAR; 2016.
- Jaffe A, Jiang D, Huang D. Drug-abusing offenders with co-morbid disorders: Problem severity, treatment participation, and recidivism. Journal of Substance Abuse Treatment. 2012;43:244-50.
- Holt M, Treloar C, McMillan K, Schultz L, Schultz M, Bath N. Barriers and incentives to treatment for illicit drug users with mental health comorbidities and complex vulnerabilities. Canberra; 2007.
- Keyes KM, Hatzenbuehler ML, Hasin DS. Stressful life experiences, alcohol consumption, and alcohol use disorders: the epidemiologic evidence for four main types of stressors. Psychopharmacology. 2011;218(1):1-17.
- Thakkar MM, Sharma R, Sahota P. Alcohol disrupts sleep homeostasis. Alcohol. 2015;49(4):299-310.
- Nutt D, Wilson S, Paterson L. Sleep disorders as core symptoms of depression. Dialogues Clin Neurosci. 2008;10(3):329-36.
- Victorian Government Department of Human Services. Dual diagnosis: key directions and priorities for service development. Melbourne: Government of Victoria; 2007.
- National Academies of Sciences E, and Medicine,. Ending discrimination against people with mental and substance use disorders: The evidence for stigma change. Washington (DC): National Academies Press; 2016.
- Latalova K, Kamaradova D, Prasko J. Violent victimization of adult patients with severe mental illness: a systematic review. Neuropsychiatric Disease and Treatment. 2014;10:1925-39.
- World Health Organization and Calouste Gulbenkian Foundation. Social determinants of mental health. Geneva: World Health Organisation; 2014.
- Hawkins D. Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: implications for substance abuse prevention. Psychological Bulletin. 1992.
- Hall W, Degenhardt L, Teesson M. Reprint of “Understanding comorbidity between substance use, anxiety and affective disorders: Broadening the research base”. Addictive Behaviors. 2009;34(10):795-9.
- Trewin D, Madden R. The health and welfare of Australia’s Aboriginal and Torres Strait Islander peoples. Canberra, Australian Bureau of Statistics. 2005.
- Demant D, Hides L, Kavanagh DJ, White KM, Winstock AR, Ferris J. Differences in substance use between sexual orientations in a multi-country sample: Findings from the Global Drug Survey 2015. Journal of Public Health. 2017;39(3):532-41.
- Baker A, Baker A, Ivers RG, Baker A, Ivers RG, Bowman J, et al. Where there's smoke, there's fire: high prevalence of smoking among some sub-populations and recommendations for intervention. Drug and alcohol review. 2006;25(1):85-96.
- Irving HM, Samokhvalov AV, Rehm J. Alcohol as a risk factor for pancreatitis. A systematic review and meta-analysis. Jop. 2009;10(4):387.
- Stenbacka M, Leifman A, ROMELSJÖ A. Mortality and cause of death among 1705 illicit drug users: a 37 year follow up. Drug and alcohol review. 2010;29(1):21-7.
- Brown S, Birtwistle J, Roe L, Thompson C. The unhealthy lifestyle of people with schizophrenia. Psychological medicine. 1999;29(3):697-701.
- Taylor D, McAskill R. Atypical antipsychotics and weightgain—a systematic review. Acta Psychiatrica Scandinavica. 2000;101(6):416-32.
- Beebe LH, Tian L, Morris N, Goodwin A, Allen SS, Kuldau J. Effects of exercise on mental and physical health parameters of persons with schizophrenia. Issues in mental health nursing. 2005;26(6):661-76.
- Greenhalgh E, Scollo M, Winstanley M. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2020.
- Kenny A, Kidd S, Tuena J, Jarvis M, Roberston A. Falling through the cracks: Supporting young people with dual diagnosis in rural and regional Victoria. Australian Journal of Primary Health. 2006;12(3):12-9.
- Mortlock KS, Deane FP, Crowe TP. Screening for mental disorder comorbidity in Australian alcohol and other drug residential treatment settings. Journal of Substance Abuse Treatment. 2011;40(4):397-404.
- Hinton M, Edwards J, Elkins K, Wade D. Problematic drug use in young people with first episode psychosis. Drug Use and Mental Health. 2009:165-78.
- Siegfried N. A review of comorbidity: major mental illness and problematic substance use. Australian and New Zealand Journal of Psychiatry. 1998;32(5):707-17.
- Kay-Lambkin F, Baker A, Lewin T. The'co-morbidity roundabout': a framework to guide assessment and intervention strategies and engineer change among people with co-morbid problems. Drug and Alcohol Review. 2004;23(4):407-23.
- Kingston R, Marel C, Mills K. A systematic review of the prevalence of comorbid mental health disorders in people presenting for substance use treatment in Australia. Drug and Alcohol review. 2016;36(4):527-39.
- Proudfoot H, Teesson M. Challenges posed by co-occurring disorders in the clinical and service systems. Drug Use and Mental Health: Effective Responses to Co-Occurring Drug and Mental Health Problems Melbourne: IP Communications. 2008:65-77.
- Kavanagh D. Treatment of comorbidity. In: Teesson M, Burns L, editors. National Comorbidity Project. Canberra: Commonwealth Department of Health and Ageing; 2001.
- Deady M, Barrett E, Mills K, Kay-Lambkin F, Haber P, Shand F, et al. Effective models of care for comorbid mental illness and illicit substance use: An Evidence Check review brokered by the Sax Institute for the NSW Mental Health and Drug and Alcohol Office. 2014.
- De Ruysscher C, Vandevelde S, Vandersplasschen W, De Maeyer J, Vanheule S. The concept of recovery as experienced by persons with dual diagnosis: a systematic review of qualitative research from a first-person perspective. Journal of Dual Diagnosis. 2017;13(4).
- Adlaf EM, Hamilton HA, Wu F, Noh S. Adolescent stigma towards drug addiction: Effects of age and drug use behaviour. Addictive behaviors. 2009;34(4):360-4.