Mental Health


Mental Health Review Paper 2018 Part C


Prevalence of common mental health conditions

Worldwide, surveys have shown that over their entire life span, more than 25% of individuals develop one or more mental or behavioural disorders (WHO, 2001). This means that potentially one in four families has at least one member currently living with a mental disorder.


The ABS Australian Health Survey

This survey reports on levels of psychological distress and mental and behavioural conditions. The last survey was conducted in 2011-12. It found that about one in ten adults (10.8% or 1.8 million people) experienced high or very high levels of psychological distress, and that the most common conditions were mood (affective) disorders such as depression and anxiety (ABS, 2012).

The ABS National Survey of Mental Health and Wellbeing

The last survey was conducted in 2007. It provides much of the information we have about prevalence in Australia of the most common types of mental health conditions. The survey collects information on:

  1. Anxiety disorders;
  2. Affective disorders; and
  3. Substance Use disorders

The 2007 Survey found that 45% of Australians aged 16-85 years had a mental disorder at some point in their life (ABS, 2008).

The ABS Survey of Disability, Ageing and Carers

The last survey conducted in 2012 found that almost one in five people with disability (19% or 813 900 people) reported a mental or behavioural disorder as the long term health condition causing them the most problems.

General Practitioner Mental Health-related Services

The Australian Institute of Health and Welfare estimates that just over 12% of GP encounters in 2012-2013 were mental health-related (nearly 15 million GP encounters). There is an annual average increase of nearly 5% in mental health-related GP encounters since 2008-2009. Depression was the most common presentation.

The ten most frequent mental health problems managed by GPs are: Depression, anxiety, sleep disturbance, acute stress reaction, tobacco abuse, dementia, schizophrenia, drug abuse, alcohol abuse, and affective psychosis.

Other Victorian Statistics

Approximately one in five (20%) of Victorians live with mental illness. Anxiety and depression are the most common disorders. (VIC, 2015)

The Australian Institute for Health and Welfare publishes data for Medicare subsidised mental health-related GP services for Victoria.

The Victorian government publishes information from a number of health surveys, including the Victorian Population Health Survey, which shows prevalence for regional Victorian areas.

Most people seek help from their general practitioner for mental health problems in Victoria. (VIC, 2015)

Prevalence of less common mental health conditions

Statistic vary, but it is estimated that people living with lower prevalence mental disorders such as schizophrenia and other psychoses affect another 1-2% of the adult population. Although they are relatively uncommon, these conditions account for about 80% of Australia’s spending on mental health care. (CTH, 2009)

It is also estimated that 2-3% of Australian adults have severe disorders based on an analysis of diagnosis, intensity of symptoms, duration of illness, and the degree of disability caused. About half of these have a psychotic illness (usually schizophrenia or bipolar affective disorder), and others have severe and disabling depression or anxiety disorders. (CTH, 2009)

The National Survey of People Living with Psychotic Illness 2010 found in its survey of public and non-government mental health services that an estimated 0.31% of the population aged between 18 and 64 years had a psychotic illness and were in contact with public specialised mental health services at a given time. Over a 12 month period, it was estimated that 0.45% of the population have a psychotic illness. This equates to nearly 64 000 people between the ages of 18-64. (CTH, 2011)

This survey found that the most common psychotic disorder experienced by the survey respondents was schizophrenia.

When the 2010 survey is compared with results from the 1997-98 National Survey of Psychotic Illness some improvements can be noted: more people experienced periods of good recovery in between multiple episodes of psychotic illness, and the proportion of people experiencing deterioration due to chronic psychotic illness has halved. (CTH, 2011)

Admitted Patient Mental Health-Related Care

Hospital separation event data can be accessed through the Australian Institute of Health and Welfare Admitted Patient Mental Health-Related Care statistics. Patients are either hospitalised in a psychiatric hospital or unit and received specialised psychiatric care, or are hospitalised in a general ward without specialised psychiatric care. (AIHW, 2012) Data is available by States and Territories as well as nationally.

Community Mental Health Care Contacts

The Australian Institute of Health and Welfare regularly measure the numbers of community mental health care contacts. People aged 25-34 usually comprise the highest proportion of community mental health care contacts.

Of all community mental health care service contacts, schizophrenia is usually the most frequently recorded principal diagnosis, followed by depressive episode, and bipolar affective disorders.

Emergency Department Mental Health Related Presentations

Emergency Departments are often used as an initial point of care for people needing mental health services for the first time, and as an alternative point of care for people needing after-hours mental health services. (AIHW, 2012)

Data from emergency departments will not capture all mental health-related presentations, therefore these statistics represent an under-reporting of the actual number of mental health-related contacts. For example, in 2012 the Australian Institute of Health and Welfare noted that although there were a total of 177 400 Australian public hospital emergency department occasions of service with a mental health-related principal diagnosis, the AIHW estimated that it was more likely to be 243 444 mental health-related occasions of service. (AIHW, 2012)

Victoria has the lowest rates of emergency department mental health-related presentations of all the states and territories. The differences between the States and Territories are explained in a variety of ways. In particular, higher rates in the Northern Territory may indicate a greater reliance on this type of care in NT. Other variances may be explained by differences in population characteristics, health-care systems, and service delivery practices.

Residential Mental Health Care Services

The Australian Institute of Health and Welfare collects data from government-funded specialised mental health care services based in a domestic-like environment (but not those funded under the Aged Care Act 1997). Their services may include rehabilitation, treatment or extended care. People aged 35-44 usually comprise the highest proportion of residential care episodes, and have the highest number of episodes per 10 000 population.

When population size is accounted for, Aboriginal and Torres Strait Islander Australians access residential services at more than double the rate of non-Indigenous Australians. The rate of episodes for Australian-born residents is also much higher than the rate for those born overseas.

The most common principal diagnosis recorded for residents who have a mental health-related residential care episode is schizophrenia. Residential Mental Health Care Service statistics are also available by state and territory.

Psychiatric Disability Support Services

The Australian Institute of Health and Welfare also collects data concerning the use of psychiatric disability support services. Other AIHW information can be found on their Mental Health Services in Australia portal.

Victorian Statistics

  • AIHW Community Mental Health Care Service Contacts - Victorian statistics for mental health care service contacts.
  • AIHW Victorian Emergency Department Presentations - Emergency Department presentations with mental-health related principal diagnosis for Victoria.
  • AIHW Hospital Separation Data - Reports hospital separation data with specialised psychiatric care for Victoria.
  • AIHW Residential Mental Health Care Episodes - Residential mental health care episodes for States and Territories by principal diagnosis, Indigenous status, age and sex and other variables.


Two or more mental disorders commonly occur together in the one individual. The ABS National Survey of Mental Health and Wellbeing 2007 found that 3.2% of respondents reported comorbidity of two or more mental disorders in the previous 12 months. (ABS, 2008) Anxiety and depressive disorders commonly occur together, as do mental disorder and substance use and dependence. (WHO, 2001)

The ABS National Survey of Mental Health and Wellbeing 2007 found that 11.7% of respondents reported comorbidity of mental health disorder and physical condition in the previous 12 months. Around one third of those had two or more disorders – either a physical and mental disorder, or more than one mental disorder. (ABS, 2008) Physical health problems coexist with mental disorders such as depression, and can also predict the onset and persistence of depression. (WHO, 2001)

The presence of comorbidity has implications for the identification, treatment and rehabilitation of affected individuals, as well as for the impact and burden on the individual and their carers and families. (WHO, 2001)

Prevalence in population groups

  • Women

Women experience higher rates of mental disorders than men, except for substance use disorders. (ABS, 2008)

  • Men

While women are at higher risk of most mental disorders, prevalence of the less common psychotic disorders is higher for men than for women. 59.6% of people with psychosis are male. Men aged 25-34 years have the highest rates of psychotic illness (0.52% total population). (CTH, 2011)

Men also have almost three times the fatal burden for mental illness and behavioural disorders than women. (AIHW, 2010)

  • Children and Young People

An estimated fourteen percent of Australian children score in the clinical range for mental health problems. (DH, 2015) Findings from the child and adolescent component of the National Survey of Mental Health and Wellbeing are published by the Department of Health.

The AIHW report Young Australians: Their health and wellbeing found that one of the gaps in our knowledge is prevalence rates of mental health disorders among 12-15 year olds. (AIHW, 2011)

The National Survey of People Living with Psychotic Illness 2010 showed that over half the women affected by psychosis have children of any age, and around a quarter of males with psychosis have children of any age. (CTH, 2011)

Adolescence and young adulthood is a critical period of mental and physical development and transition. Vulnerability is heightened at this time – 76% of people who experience mental disorder during their lifetime will first develop a disorder before the age of 25. (ABS, 2010)

Adolescents with mental health problems report a high rate of suicidal ideation and other health-risk behaviours such as smoking, drinking and drug use. (Arney, 2000)

The prevalence of mental disorders in the 16-24 year age group is 26% - that is, one in four young people have experienced at least one mental disorder (AIHW, 2011). The most commonly reported disorders are anxiety disorders, substance use disorders and affective disorders. Of the anxiety disorders, the most prevalent types reported are post-traumatic stress disorder and social phobia. Harmful use of alcohol was the most common substance use disorder. (AIHW, 2011)

Mission Australia report on the Annual Youth Survey. In 2014 they reported specifically on youth mental health and found:

  • Over one fifth of young people met the criteria for have a probable serious mental illness
  • Females were twice as likely as males to be classified as having a probably serious mental illness
  • Respondents who identified as Aboriginal or Torres Strait Islander have much higher rates of probable serious mental illness
  • Respondents who reported a disability had much higher rates of probable serious mental illness. (Mission Australia, 2015)

The ABS Mental Health of Young People survey shows that young people also have a relatively low use of mental health services, with GPs being the most frequently used health professional. Those with a severe level of impairment were more likely to use mental health services. (ABS, 2010)

AIHW Hospital separation data shows the percentage of all separations for young people for a principal diagnosis of mental and behavioural disorders. The leading causes of hospital separation for mental and behavioural disorders are mood disorders, disorders due to psychoactive substance use, and neurotic, stress-related and somatoform disorders. (AIHW, 2011)

  • People with a Disability

The ABS National Survey of Mental Health and Wellbeing found that 43% of people with a profound or severe core-activity limitation had experienced a mental disorder in the previous 12 months. (ABS, 2008)

  • Aboriginal Australians

Information sourced from mental health services are likely to underestimate the actual rates of mental illness within Aboriginal communities for reasons of both identification practices, and because many Aboriginal people do not access mainstream services. Even so, Aboriginal people are over-represented in mental health care throughout Australia. (Garvey, 2008)

Australia-wide Indigenous Australian’s are hospitalised for psychiatric disorders at a much higher rate than non-Indigenous Australians. (Hunter, et al., 2012) They are 2-3 times more likely than non-Indigenous Australians to be admitted to hospital for intentional self-harm. (Cunningham, 2012)

The National Aboriginal and Torres Strait Islander Health Survey, the National Health Survey and the National Aboriginal and Torres Strait Islander Social Survey record high or very high levels of psychological distress in the Indigenous population. (AIHW, 2011)

The statistics for Victoria show that Aboriginal Victorians are about three times more likely to experience high/very high levels of psychological distress than non-Indigenous people, particularly those living in remote areas. (VIC, 2013)

The higher levels of psychological distress reported by Aboriginal people are consistent with the relative frequencies with which they experienced family stressors. The most commonly reported family stressors are:

  • Death of a family member or friend
  • A serious illness
  • Inability to get a job
  • Mental illness
  • Trouble with the police
  • Alcohol-related problems
  • Involuntary loss of a job
  • Pregnancy
  • Drug-related problems.

Aboriginal and Torres Strait Islander people aged 15 years and over are 1.4 times more likely than non-Indigenous people to have experienced one or more of these specific stressors. (ABS, 2013) Aboriginal Australians have higher rates of suicide, disability and chronic disease, and are exposed to high levels of racism, trauma and grief. (Cunningham, 2012)

The Australian Institute of Family Studies longitudinal study Footprints in Time reports on the frequency with which parents have been feeling depressed, anxious, angry or impulsive, and their experience of significant stressful life events. The study found that around half the parents reported experiencing three to six major life events in the past 12 months. The three most frequently experienced life events parents had experienced were a pregnancy or the birth of a child, the death of a close family member or friend, and that they had felt crowded where they lived, moved house, or had housing problems. (DFHCSIA, 2009)

The Western Australian Aboriginal Child Health Survey (2005) used carer reports to assess the risk of emotional and behavioural difficulties for Aboriginal children aged 4-17 years. The study found that:

  • nearly a quarter of Aboriginal children in that age group were at a high risk of clinically significant emotional or behavioural difficulties (compared with 15% in non-Indigenous children).
  • 16% of young people aged 12-17 had seriously thought about ending their own life in the 12 months prior to the survey (females 20%/males 12%)
  • Of those young people who had thought about suicide, 39% had also attempted suicide in the previous 12 months
  • A much larger proportion of young people at high risk of clinically significant emotional or behavioural difficulties had thought about suicide (37%) or had attempted suicide (21%) in the previous 12 months. (AT, 2005)

The Victorian Governments Aboriginal Affairs Report reports on Aboriginal presentations at emergency departments with injuries die to self-harm in Victoria, which are much higher than for non-Indigenous people. (VIC, 2013)

  • Carers

This ABS Disability, Ageing and Carers survey found that we are likely to underestimate the number of carers in the community as many people do not identify as carers despite the assistance they provide to family members and friends with disability. Women make up the majority of carers (70% of primary carers, 56% of carers overall). 37% of primary carers have a disability themselves. (ABS, 2012) (CTH, 2011)

When are they at risk?

Mental illness usually has its onset in childhood or adolescence (CTH, 2009). Two thirds of people with a psychotic illness experience their first episode before the age of 25 years. The mean age of onset is 23 years for men, and 24 years for women. (CTH, 2011)


The determinants of severe and persistent mental illness can be understood using a biopsychosocial framework. This helps us to understand the complex interplay of biological, psychological, and social factors that determine a diagnosis of mental illness.

World Health Organisation: Interaction of the biopsychosocial model (WHO, 2001)

Genes create the framework for early responses to the world, but the continuous interaction over a lifetime with personal and social environments may lead to the specific psychological and behavioural responses we recognise as mental illness. These factors interact throughout the life span to increase or decrease the likelihood of the onset of a disorder, and determine its clinical form and outcome. Factors which create vulnerability appear to have a multiplying rather than an additive effect: the risks associated with having at least two determinants or risks are significantly greater than the sum of those individual risks.


Most significantly, these environmental factors not only influence the path from health to illness, but also from illness to recovery. Some individuals become severely disabled by their condition, while others are more able to work towards recovery. (Ellis, 2001) In the context of mental illness, ‘recovery’ means ‘the challenge of maintaining or rebuilding a meaningful and satisfying life…whether or not the symptoms can be eliminated’. (Fossey, 2012)

In a public health context, these determinants not only affect the development and onset of severe and persistent mental illness, but also have a determinant effect on rates of hospitalisation, levels of disability, rates of help-seeking, rates of relapse, and adherence to treatment.

Biological determinants


Genes are an important factor for determining risk of both psychotic and non-psychotic illnesses. Most illnesses are caused by a number of genes with varying contributions.

  • For bipolar disorder, for example, the risk for children of an affected person is 20% (1-2% for children of non-affected parents). Fifty percent of people with bipolar disorder have a parent with a mood disorder. (MHRI, 2003) Australian research on adolescents with a genetic risk of bipolar disorder (with either a parent or sibling with bipolar disorder) found that those adolescents had reduced brain activity in a specific part of the brain known to regulate emotional responses. (Roberts G, 2012)
  • Risk of schizophrenia is also heightened in the children of an affected person (10%, compared with 1% for people without an affected family member). Genetic contribution to schizophrenia is estimated to be around 60%. (Barbato, 1996) (Ellis & Hickie, 2001)
  • Genetic predisposition for PTSD is calculated to be 60%. It may be caused by multiple genes. (Ellis & Hickie, 2001)

However, clinical presentation is not entirely determined by genetics.

Physiology and the brain

Some mental illnesses are linked to disruption of neural communications. If the nerve cells in the brain are unable to facilitate communication along neurotransmitters (either through brain damage, drug use, or some life experience/event) long-term changes to the way an individual thinks, expresses emotion, and behaves can occur. (HealthInfoNet, 2013)

Some severe and persistent mental illnesses may be neurodevelopmental in origin, though in many instances it is unknown whether the changes in brain function associated with these illnesses are a causal factor or a consequence of mental illness. There is now a body of evidence that suggests that variations in the quality of early life environments may alter the epigenetic regulation of genes and affect future disease risk. (Sweeny, 2014)

  • In schizophrenia exposure in utero or in early life to factors affecting brain development may lead to changes in the brain which increase the risk of schizophrenia. Low-birth weight, exposure to influenza during the second trimester of pregnancy, and obstetric complications at birth are linked to risk. This may be due to the impact these have on the structural development of the brain. (Ellis & Hickie, 2001)
  • Abnormal cell metabolism may play a role in bipolar disorder. Imaging of brain cells can detect differences in metabolism in the cerebral white matter and cerebellar regions of people affected by bipolar disorder but not in the brains of people who do not have bipolar disorder. (Johnson, 2015)
  • Psychosis is characterised by rapid and pronounced cerebral grey matter loss – a tissue loss which occurs before exposure to antipsychotic drugs. The brain changes appear to be part of the natural course of psychotic disorders.
  • Personality disorders may be associated with impaired regulation of the brain circuits that control emotion. (PHAC, 2006)
  • Babies born with extremely low birthweight whose mothers received a full course of steroids prior to giving birth are at greater risk for psychiatric disorders such as depression, anxiety disorders or ADHD. (Lieshout, 2015)
  • Exposure to stressors during early childhood has been associated with persistent brain hyper-reactivity, and also to the increased likelihood of adult depression. Affectionate and stable relationships of care during childhood is of crucial importance for children to develop normally. When children are not nurtured they are more likely to develop mental and behavioural disorders. (WHO, 2001)
  • Alcohol and other substance use have psychiatric implications. Substance, or experience-driven alterations in synaptic connections may produce long term changes in thinking and behaviour. (WHO, 2001)
  • Some medical disorders can lead to psychiatric illness; for example, multiple sclerosis, endocrine disorders, infections like glandular fever and HIV, as well as injuries to the brain. Several chronic illnesses are associated with an increased prevalence of major depression. They include stroke and heart disease, obesity, arthritis, cancer and dementia. (PHAC, 2006) Some clinically prescribed medications will also have psychiatric side-effects. (Ellis & Hickie, 2001)

Determinants which influence and interact with genetic and physiological factors include both the psychological and social determinants of mental illness.

Psychological determinants

Personality can be defined as the way in which people relate to others, react to interpersonal stimuli, and evaluate themselves over time. Some people have a wide range of responses which help them to cope with different circumstances. Others have a more limited range which creates a vulnerability when circumstances become challenging.

Some personality styles are associated with different severe and persistent mental illness. For example, a hypomanic personality style is associated with risk of bipolar disorder. (Lancaster, 2015)

Social determinants

The action of social determinants on mental illness will interact to reduce or enhance underlying genetic vulnerability. Adverse social conditions may affect mental health by creating chronic stress, triggering the arousal of neural and somatic stress response. The degree of vulnerability of any individual will be influenced by their genetic make-up, psychological resources, and accumulation of negative life events. (Fisher, 2010) For instance, twin studies have found that the risk of developing depression or anxiety in adult life is comprised of: 30% genetic factors, 10% childhood factors, and 60% current environmental factors. (Ellis & Hickie, 2001)

Some genetic risk factors may be exacerbated by environmental factors such as; substance use or poor nutrition during pregnancy; childhood neglect; and trauma. These may have a negative effect on mental health outcomes of the child. (WHO, 2001) (HealthInfoNet, 2013)

Some genetic risk factors may be mitigated through environmental intervention. For example, early intervention for people with a history of depression in both parents may reduce both the incidence and the severity of the illness. Factors such as social participation and quality caring relationships will also have a positive effect on mental health outcomes. (Ellis & Hickie, 2001)

Socio-economic status

Most traditional indicators of socio-economic status – education, employment, income, home ownership, geographic disadvantage – have all been associated with prevalence of very high psychological distress, as well as substance use disorders. (Cunningham, 2012) (WHO, 2001)

There are three main models of life course which explain the influence of socio-economic status on health generally:

  1. The timing model: SES-related factors have the greatest influence on adult health if experienced during specific developmental periods;
  2. The accumulation model: the risk for poor adult health increases with increasing intensity of socioeconomic disadvantage and increasing duration of exposure;
  3. The change model: change in SES levels may affect health either positively or negatively, depending on the direction of change between lower and higher levels of SES. (Sweeny, 2014)

There is strong evidence showing that poverty increases the risk for, course of, and recovery from, mental illness. The effects of poverty accumulate over time. (WHO, 2001)

Children living in poverty are more likely to be exposed environmental risk factors such as illness, family stress, poor social support, parental mental illness, chaotic home environments, alcohol and drug use, family violence, child abuse, unsafe neighbourhoods, community crime and violence. The risks affect the pre-natal environment, as well as childhood and adolescence. (Robinson, 2013) (Webb, 2013)

Intergenerational persistence of poor mental health is transmitted from parent to child not only via a genetic pathway, but also as a consequence of the low socioeconomic status and social functioning associated with parental mental illness. (Johnston, 2013)

Unemployment also has links to mental illness, particularly when the overall rate of unemployment is low. (Ellis & Hickie, 2001)

Age and gender

Mental illness affects women and men of different ages differently. Anxiety and depressive disorders are more common among women, and substance use disorders and antisocial personality disorders are more common among men. There are gender differences in self-care and prevention behaviours, and in responses to a variety of stressors, but it is unclear to what extent gender itself is a determinant. Patterns of risk, psychological, and social factors, such as rates of family violence against women, may account for much of the gender difference. (WHO, 2001)

Social networks and social capital

Having caring intimate relationships protects against most forms of mental illness. In times of crisis, supportive social networks are particularly crucial. These networks include religious and cultural groups, as well as family and friends. (Ellis & Hickie, 2001) The social and emotional environment of the family is strongly linked to the course of, and recovery from, severe and persistent mental illness. (WHO, 2001)

Social capital refers to the strength of personal support networks and the ability to access this support. It encompasses levels of trust, collaboration and mutual responsibility. High levels of social capital have a protective effect against mental illness.

Life events

Life events tend to affect individuals rather than populations. The impact of any event on an individual will depend on both its severity and duration, as well as on the availability of social support and other personal factors. They are particularly harmful when experienced at a young age. (WHO, 2013) For example, a diagnosis of borderline personality disorder has been particularly associated with experiences of early childhood physical and sexual abuse. (PHAC, 2006)

Life events can include: chronic health conditions, exposure to maltreatment and neglect, substance use, exposure to discrimination and human rights violations, and exposure to natural disaster. (WHO, 2013) Australian studies have found that the impact of drought on rural communities has an impact on mental health, and the greater the severity of drought, the greater the impact on mental health. (Edwards, 2014)

Conflict and disaster affect population groups and have repercussions for mental health. The most frequent diagnosis is post-traumatic stress disorder, along with depressive or anxiety disorders (WHO, 2001). These social factors which influence the risk of onset and severity of mental illness are discussed in greater depth below in Risk and Protective Factors.

A framework for understanding determinants

A common framework showing the links between determinants and risk factors, with examples, is as follows: (Selzer, 2014)




Predisposing factors

Genetic, birth trauma, brain injury, illness, medication, drugs/alcohol, pain

Personality, modelling, unconscious defences, conscious coping strategies, self-esteem, body image, cognition, childhood trauma

Socio-economic status, trauma, family disruption, family violence

Precipitating factors

Medication, trauma, drugs/alcohol, acute illness, pain

Stage of life, loss/grief, treatment, stressors

Work, finances, connections, relationships

Perpetuating factors

As above

As above

As above

Protective factors

Physical health

Engagement, insight, adherence, coping strategies, intelligence

Some good relationships, safe housing

Risk & Protective Factors

Exposure to risk factors will increase the likelihood of onset, the severity of symptoms, and the duration of mental illness. Some risk factors, such as the pre-natal environment, may have an effect a long time before the emergence of a mental illness. Other risk factors, such as the death of a parent, may have a more immediate effect. It is often the cumulative effect of many risk factors, combined with a lack of protective factors, which will precipitate the onset of mental illness (WHO, 2004).

This resource is focused on risk factors to which exposure can be modified by public health and health promotion intervention.

Protective Factors

Protective factors can reduce the likelihood of, or ameliorate responses to, environmental hazards. The presence of protective factors has been shown to reduce risk regardless of the number of risk factors. The Commonwealth government published the following list of protective factors which potentially influence the development of mental health problems and mental disorders in individuals (particularly children).

Protective Factors for Mental Health Problems and Mental Disorders (McCanlies, Mnatsakanova, Andrew, Burchfiel, & Violanti, 2014)

Recent research into post-traumatic stress disorder with police officers found that personality traits such as resilience, satisfaction with life and a grateful disposition are protective factors (McCanlies, Mnatsakanova, Andrew, Burchfiel, & Violanti, 2014).

VicHealth also recognises that social support and social networks have a beneficial effect on mental health and are associated with reduced experience of psychological distress (VicHealth, 2005).

Risk Factors

The Commonwealth government published the following list of risk factors which potentially influence the development of mental health problems and mental disorders in individuals (particularly children).

Risk Factors for Mental Health Problems and Mental Disorders (Commonwealth Department of Health and Aged Care, 2000)

Some risk factors are common to many mental disorders, and other risk factors are disease specific (WHO, 2004).

Pre-Natal Risk Factors

Intrauterine exposure to risk factors may have consequences for the child’s long-term behavioural and emotional well-being. The research in this field has been inspired by the developmental origins of health and disease model (DOHaD), which sees a link between foetal development and the non-communicable diseases which emerge in adulthood. Theoretically, it is understood that responses to in utero experiences lead to biological changes in the foetal brain. Brain development, in the form of epigenetic programming, cell distribution, and establishment of endocrine systems and metabolic activity, is believed to vary depending on the timing, type, dosage and duration of a number of environmental exposures (Robinson, 2013) (Lewis A, 2014).

It can be argued that some of the findings regarding pre-natal influence on mental illness may also be explained by the post-natal environment, and research is yet to determine the degree of association. A note of caution: there is the potential for ‘mother blaming’ in the interpretation of this research.

Those risk factors for which we now have some evidence include:

Physical Health Factors

Lifestyle factors are potentially modifiable risk factors and a good target for prevention intervention.

  • Famine: children who experience famine in utero have higher rates of mental illness, including schizophrenia.
  • Smoking: maternal smoking during pregnancy increases the child’s risk for both externalising (for example, ADHD, conduct disorder, antisocial behaviour) and internalising (for example, depression, anxiety) behaviours. One study found that mothers who cease smoking early in pregnancy will alleviate the risk. However, the results of these studies could be interpreted to suggest that psychosocial processes may be a factor: that is, that quitting smoking shows higher self-efficacy and positive parenting practices which will impact mental health outcomes.
  • Alcohol: Extreme levels of exposure to alcohol is highly damaging to the unborn child. However, studies of pregnant women who consume low levels of alcohol show that this is not associated with developmental risk. As with the example of smoking cessation above, low to moderate alcohol intake may also imply that exerting self-control is characteristic of better parenting practices.
  • Obesity: a 2013 study found that the children of women who were overweight or obese before pregnancy were more likely to have significant problems, including major depression, during childhood and adolescence. Once again, this may imply that the later influence of an obesogenic environment (such as poor quality diet and sedentary behaviour) also has an impact on mental health.
  • Vitamin D Status: there may be a relationship between low vitamin D in pregnant women and serious mental illness in children. Further research is required (Robinson, 2013).

Maternal Mental Health

  • Stress: children of women who experience stressful events during pregnancy are at increased risk, with that risk increasing with each additional stressful event experienced. One study found that for women who experienced six or more stressful life events, their children had about four times the risk of developing a mental health problem during childhood. There appears to be no difference in risk if the stress occurs earlier or later in the pregnancy (Robinson, 2013). Mild stress exposure may not always be a risk factor. Some studies have shown that mild stress exposure in late pregnancy may well be advantageous for the child. (Lewis A, 2014)
  • Unwanted pregnancy: Risk of psychosis in adulthood has also been found if the mother reported that a baby was unwanted during pregnancy (Bentall & Fernyhough, 2008).
  • Depression: perinatal exposure to maternal depression is associated with some dysregulation of the child’s response to stress and may be a foetal programming pathway for the transmission of depression to the child. Research in this area is limited and associations between pre- and post-natal depression have not been clearly differentiated. (Lewis A, 2014)

Teratogenic and Neurotoxic Exposures

Teratogens are agents which alter foetal development. For instance, chemicals with endocrine-disrupting properties are related to adverse neurodevelopmental outcomes.

  • Prenatal exposure to alcohol, cigarettes, cocaine, marijuana, benzodiazepines, methamphetamine, and some prescribed medications have been associated with increased risk of emotional, behavioural and cognitive problems. The association appears to be independent of the social factors which may be associated with their use.
  • Psychotropic medications such as antidepressants, antipsychotics and mood stabilizers are now the focus of research due to the increasing rates of exposure in the community. Risks of exposure must be balanced against the harms of withholding treatment in these cases. (Lewis A, 2014)

Environmental toxins are beyond the control of the individual, yet are still important modifiable risk factors.

  • Lead persists in the environment though exposure has been markedly reduced. Pre-natal, lifetime and current exposure are all important and results in adverse outcomes across a broad ranging neurodevelopmental spectrum.
  • Other historic environmental toxins include methyl mercury and PCBs (polychlorinated biphenyls)
  • Modern chemicals are now the subject of research, including manganese, cadmium, and other endocrine-disruptors such as BPAs (bisphenol A), organochloride pesticides and organophosphate pesticides.

Early Life Trauma

It has been estimated that childhood trauma affects five million Australian adults. Traumatic experience takes many forms, but is characterised by the powerlessness of the child to prevent or minimise it (Kezelman, Hossack, Stavropoulos, & Burley, 2015).

Experiencing trauma early in childhood has a significant impact on brain development (McAloon, 2014). The first two years of life see strong growth and development of the brain. The direction and pattern of this development is partly genetically, and partly environmentally, driven. The science of epigenetics suggests that gene expression is moderated by the environment. Alterations to genetic expression may be part of the explanation of how maltreatment affects the developing brain (Webb, 2013).

Many adverse childhood experiences can co-occur – exposure to one experience increases the likelihood of exposure to others (Putnam, Harris, & Putnam, 2013). Childhood exposure to even non-interpersonal trauma (such as parental depression or anxiety, parental alcohol and drug abuse) is associated with severe and persistent mental illness (Putnam, Harris, & Putnam, 2013) (Westphal, et al., 2013). The association between childhood trauma and psychosis is strong and significant, even after controlling for genetic risk (Van Winkel, Van Nierop, Myin-Germeys, & Van Os, 2013) (Bentall, Wickham, Shevlin, & Varese, 2012). A rigorous meta-analysis of studies into the associations between trauma and psychosis found that sexual abuse, physical abuse, emotional abuse, bullying, parental death and neglect were all individually related to an increased risk of psychosis (Varese, et al., 2012).

Childhood trauma and adversity have an intergenerational effect, as parents who suffer in childhood struggle to provide a positive environment for their own children (Read & Bentall, 2012). In a recent study of the family history of people experiencing comorbid mental illness and substance abuse, those with two or more first-degree relatives with alcohol, drug or psychiatric problem histories were more likely to report histories of physical, sexual and/or emotional abuse than the other respondents (Wilson, Bennet, & Bellack, 2013).

People experiencing psychotic illnesses with a history of early life trauma may experience persistent interpersonal difficulties which prevent them from engaging effectively with services and obtaining treatment (Bentall & Fernyhough, Social Predictors of Psychotic Experiences: Specificity and psychological mechanisms, 2008).

The strongest evidence for risk is found in the following categories of trauma:

Inter-parental violence

Children in homes where inter-parent violence is present are at increased risk for psychosocial difficulties and mental illness. A 2014 study found that in that environment, the variables most strongly associated with child psychosocial impairment were the father’s antisocial personality traits, and the interpersonal hostility within the home (Febres, et al., 2014).

Child abuse

Physical, sexual, and emotional abuse are associated with all mental conditions. Child abuse has a dose-response relationship with both onset and symptom severity of severe mental illness (Bentall, Wickham, Shevlin, & Varese, 2012).

Sexual abuse, particularly for women, results in the most potent childhood trauma (Putnam, Harris, & Putnam, 2013) (Perrin, et al., 2014). In a 2013 study on a large number of people experiencing severe mental illness found that childhood sexual abuse was the most commonly experienced trauma (Lu, 2013).

Investigation of an extensive UK survey of psychiatric morbidity found a specific and significant association between childhood sexual abuse (rape – not sexual touching or talk) and auditory-verbal hallucinations. Experiences of other types of physical abuse predicted paranoia and auditory-verbal hallucinations (Bentall, Wickham, Shevlin, & Varese, 2012).

People exposed to childhood physical or sexual abuse are more likely to: be admitted to a psychiatric hospital; have earlier, longer and more frequent admissions; take more psychiatric medication; self-harm and attempt suicide; and have greater global symptom severity (Read & Bentall, 2012).

Various studies have found: that 40% of people experiencing chronic depression had experienced sexual abuse during childhood; that survivors of child sexual abuse account for 34% of all presentations across the mental health sector; that adults who had been abused as children were 2.5 times more likely to have major depression and 6 times more likely to have PTSD; that 81% of adults diagnosed with Borderline Personality Disorder, and 90% of adults diagnosed with Dissociative Identity Disorder, were sexually and/or physically abused as children, and that 35-70% of female mental health patients self-report a childhood history of abuse (Kezelman, Hossack, Stavropoulos, & Burley, 2015).


Trauma may be experienced in the form of neglect. A child’s developmental needs may not be met causing neurodevelopmental change (McAloon, 2014). The UK survey psychiatric morbidity survey found a significant relationship between being brought up in institutional care and the experience of paranoia. That study also found that quality foster care can repair disturbed attachment styles in children who have experienced adversity and is a protective factor for mental illness (Bentall, Wickham, Shevlin, & Varese, 2012).

Other Trauma

Other childhood traumas found to have an association with mental ill health include: dysfunctional parenting (particularly ‘affectionless overcontrol’), separation from parents in early life, parental substance misuse, criminal behaviour and mental illness, childhood medical illness, and war trauma (Read & Bentall, 2012).

Life Events

Life events may also trigger, or have a cumulative effect, on relapse for people with a diagnosed mental illness. Identifying relapse risk factors has clinical implications for treatment and recovery. Understanding the importance of severity of the threat a life even presents can inform clinical intervention aimed at preventing or reducing the impact (Fallon, 2009).