Mental Illness

Mental Illness

Key Messages

  • Approximately 10-15% of older Australians suffer from a mental illness. [1,2]
  • Mental illness in older people is often unrecognised, hence, relatively few older people with mental illness are referred for specialised treatment. [3]
  • Unrecognised and untreated mental illness in adults and older adults is linked to disability, reduced quality of life, decreased adherence to treatments, increased hospital admissions, thoughts of suicide, lower life expectancy and lower rates of palliative care service use. [4-11]
  • The co-existence of advanced disease and/or cognitive impairment complicates the process of diagnosing mental illness in older people approaching the end of their life. [2,4,12-15]
  • Specialist mental health input (e.g. psychiatrists, psychogeriatricians) should be considered as part of holistic care. [16,17]
  • Adults with a severe mental illness have been identified as a particularly vulnerable group [10] yet the evidence describing hospice and palliative care for adults with serious mental illness is just emerging as an area of research. [11]
  • For people with serious mental illness, death from natural causes largely explains the mortality gap compared to the general population and this suggests that they are likely to have palliative care needs. [9,11]


This topic focuses on mental illness or mental health disorders as distinct from the broader concept of mental health and wellbeing issues.

The terms ‘mental disorder’, ‘mental illness’ and ‘mental health disorder’ are all used to describe a spectrum of mental health and behavioural disorders that can vary in duration and severity. In this evidence synthesis, the term ‘mental illness’ is used as it is the term most commonly used in the literature.

Mental illnesses are disturbances of mood, emotions, thoughts, perceptions and/or behaviours that may cause problems in functioning and distress for the person and/or those around them. [1,2] Serious mental illness, and serious and persistent mental illness are defined in the literature as prolonged (more than 2 years) or recurrent mental illness experienced by adults. [10] Mental disorders that can affect older people include anxiety disorders, mood disorders (e.g. major depression, bipolar disorder), schizophrenia, other forms of psychotic illness, substance abuse disorders and dementia. [2,3,18-20] 

Whilst mental illness is more common in people of 16-34 years of age, approximately 10-15% of older Australians suffer from a mental illness. [1,2] Certain sub-groups of older people have a higher risk of experiencing poor mental health: older carers, residents of aged care facilities, and persons with co-morbid medical conditions and/or physical problems. [2,21] It is estimated that around 35-52% of aged care residents have mild, moderate or major symptoms of depression [2,21] and between 6.5 and 58.4% have anxiety. [14] 

Evidence Summary

Older adults with a mental illness may have experienced a lifetime of chronic or relapsing mental illness, or had a recent onset of mental illness as the result of a significant stressor such as bereavement or diminished physical ill-health including diagnosis of a life-limiting illness. [2] Mental illness is often not recognised by individuals, families and health care professionals and symptoms of treatable mental illness may be wrongly attributed to ageing or to physical or environmental changes. [3] Hence, relatively few older people with mental illness are referred for specialised treatment. [3]

Adults with a severe mental illness have been identified as a particularly vulnerable group [10] as they have an increased risk of severe, concurrent health problems, lower life expectancy, poorer experience of healthcare and poorer access to health care, are often marginalised and isolated, and have a higher need of assisted living. [7-11,19] Unrecognised and untreated mental illness in adults and older adults is linked to disability, poorer quality of life, decreased adherence to treatments, increased hospital admissions, thoughts of suicide, lower life expectancy and lower rates of use of palliative care services. [4-11] However, the difference in mortality for those with serious mental illness compared to the general population is mostly due to death from natural causes and this suggests that they are likely to have palliative care needs at the end of life. [9,11]

A variety of health care professionals deliver care and support to older people with mental illness, including GPs, geriatricians, neurologists, psychiatrists and other mental health professionals, neurologists, and mental health teams (general adult and specialist for older people). [1,3] Primary Health Networks (PHNs) are required to commission psychological treatment services to support people living in residential aged care facilities. [22]


The prevalence of depression among adults with advanced cancer and in oncology may vary considerably [21,23] with estimates ranging from between 8%-24% [5,21] and as high as 38-58%. [4,21,23] It has been recognised that people and their carers accessing palliative care services can have undiagnosed psychiatric symptoms and psychiatric conditions. [4,21] Limited data are available about depressive disorders in older people receiving palliative care. [13]

The Geriatric Depression Scale (GDS), specifically designed for use with older people, is a commonly used instrument for screening depression. [24] A recent systematic review not specific to the palliative care context has recommended the Two-Question Screen for screening for depression in older people. [24] Other tools are discussed in the Evidence Synthesis.

People living with dementia are twice as likely as their peers to be diagnosed with depression; and conversely, the presence of chronic depression increases the risk of dementia later in life. [12] The interrelationship between depression, depressive symptoms, cognitive impairment and dementia means that diagnostic clarity can be challenging. [12] Hence, active treatment of depression and other comorbidities is recommended prior to an assessment for dementia. [12,22]


Anxiety as a symptom is common in the context of palliative care and it can also be a presenting feature of a wide range of medical conditions and mental health disorders that are common in the elderly including specific anxiety disorders (e.g. generalised anxiety, agoraphobia, panic disorder), depression, dementia and delirium. Hence, thorough assessment of anxiety is essential in determining appropriate intervention and management strategies. [16,17] The Geriatric Anxiety Inventory (GAI) has been validated for use in older people in residential facilities. [14] The Rating Anxiety in Dementia scale (RAID) has been used and validated with dementia patients in different settings and is commonly used as an anxiety measure used in residential aged care facilities. [14] Other tools are discussed in the Evidence Synthesis.

Treatment for Depression and Anxiety:

Although there are Australian evidence-based guidelines on the assessment and management of anxiety and depression in adult cancer patients, [25] there are no national or international guidelines for the assessment and management of anxiety in palliative care patients. [26]

Treatment for depression and anxiety is both non-pharmacological and pharmacological, [6,16] and, in the palliative context, the approach to treatment will depend on the severity of symptoms, levels of distress and the estimated course of the life-limiting illness. [6,21] Although there are Australian evidence-based guidelines on the assessment and management of anxiety and depression in adult cancer patients, [25] there are no national or international guidelines specifically for the assessment and management of anxiety in palliative care patients. [26]

Non-pharmacological management may include counselling and emotional support, [16] cognitive behavioural therapy (CBT), problem-solving therapy, group therapy, guided imagery, mindfulness-based therapy, or specialised forms of psychotherapy (e.g. meaning-centred psychotherapy, dignity therapy, art therapy, music therapy). [4,15,21] However, there is a paucity of research and high-quality evidence on psychological therapy in palliative populations. [4,15,21] Information on the pharmacological treatment of anxiety and depression (not specifically older adults) can be found in Therapeutic Guidelines (subscription required), the Oxford Textbook of Palliative Medicine (5 ed.) (subscription required), Oxford Handbook of Palliative Care (3rd ed.) (subscription required), and the Scottish Palliative Care Guidelines - Depression. [4,16,17,27-29]

Timely referral to specialist mental health providers, including psychiatrists and psychogeriatrician should be considered, particularly in cases of severe mental illness, severe and persistent mental illness and dementia. [17,29] This consultation and collaboration can assist in tailoring interventions best suited to the person’s needs.


Although more commonly associated with younger age groups, schizophrenia is one of a number of mental illnesses listed by the Royal Australian and New Zealand College of Psychiatrists as potentially developing in later life. [3] People with schizophrenia are at risk of receiving poorer end-of-life care than other patients. [8,11] They are often undertreated, avoid treatment and are about half as likely to access palliative care. [8,9,11] There has been very little research on palliative care and schizophrenia and the evidence base is low. However, in a recent scoping review of 32 studies, it was noted that due to the chronic and lifelong nature of the condition it is likely that people with schizophrenia will have symptoms as they approach older age and death. [8]

Suicide and suicidality

Most older people who die by suicide have a diagnosable mental disorder at the time of death, most commonly severe depression. [2,4] In Australia in 2018, mood disorders, including depression, were the conditions most related to suicidal deaths and associated with 39.5 % of suicide deaths of 65-84-year-olds and 23.1% of suicidal deaths of 85+ year-olds. [30] For adults aged 65 years and above, the other common factors associated with suicide were emotional states (including suicide ideation), anxiety and stress-related disorders. [30] Chronic diseases and complex health conditions were likely to be identified in older age suicides. Cancer was associated in 13.4% of suicide deaths among those aged 65 to 84, and 11.5% among those aged 85 and over. [30]

Treatment for suicidality includes active treatment of depression, hopelessness, and demoralisation. With the warning signs of an imminently impending suicide attempt (agitation and increasing anxiety, desperation, and easy access to a mode of dying), admission to hospital, one-to-one observation, careful assessment and removal from the possibility of self-harm are necessary. [4] Any patient expressing suicidal ideation (the indication that a person is likely, or is planning, to commit suicide) needs psychiatric evaluation or consultation. [8,17,28]

Quality Statement

The included systematic reviews were of acceptable to high quality. These include only two systematic reviews for mental illness specific for older people receiving palliative care. No guidelines were retrieved specific for mental illness in older people receiving palliative care.

Many reviews focus on the mental health of the adult population. Commonly found in the literature was a focus on the symptoms of anxiety and/or depression and in some cases, it was not easy to determine whether the focus was on depression and/or anxiety as illnesses or symptoms.

Page updated 11 August 2023

  • References

  • About PubMed Search

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Mental illnesses are of different types and degrees of severity. Some of the major types are depression, anxiety, schizophrenia, bipolar mood disorder, personality disorders, trauma and eating disorders.

The most common mental illnesses are anxiety and depressive disorders. While everyone experiences strong feelings of tension, anxiety, or sadness at times, a mental illness is present when these feelings become so disturbing and overwhelming that people have great difficulty coping with day-to-day activities, such as work, enjoying leisure time, and maintaining relationships.

At their most extreme, people with a depressive disorder may not be able to get out of bed or care for themselves physically. People with certain types of anxiety disorder may not be able to leave the house, or may have compulsive rituals to help them alleviate their fears.

Less common are mental illnesses that may involve psychosis. These include schizophrenia and bipolar mood disorder. People experiencing an acute episode of psychosis lose touch with reality and perceive their world differently from what is considered normal. Their ability to make sense of thoughts, feelings, and the world around them is seriously affected.

A psychotic episode may involve delusions, such as false beliefs of persecution, guilt, or grandeur. It may involve hallucinations, where the person sees, hears, smells, or tastes things that are not there.

Psychotic episodes can be threatening and confusing to other people. Such behaviour is difficult to understand for people who are not familiar with it.

Source: What is mental illness? . Mental Health and Workforce Division of the Australian Government Department of Health and Ageing (2007)


Final search

(Mentally ill persons[mesh] OR mental disorder*[tiab] OR “Mental Disorders”[Mesh:NoExp] OR mental illness*[tw] OR mentally ill[tiab] OR schizophrenia[tw] OR psychiatr*[tiab] OR bipolar[tw] OR delusion*[tiab] OR psychopath*[tw] OR personality disorder*[tw] OR anxiety[tw] OR depression[tw] OR depressive[tw] OR eating disorder[tw] OR psychosis[tw] OR psychotic[tw] OR antidepressant*[tw])