One in four older adults (aged 65 years and older) has at least one significant mental health problem/disorder.1 The prevalence of mental health problems in the oldest old (aged 85 years and older) approaches 50%. The prevalence of mental health problems in the LTC population ranges from 65 to 100%. Older adults account for 14% of the population but almost 20% of all suicides. The prevalence of psychiatric disorders in older adults is expected to double over the next 30 years, making them a priority for healthcare and social care services.2 The actual burden of mental disorders in older adults is probably underestimated because the stigma associated with mental disorders results in under-reporting of symptoms by older adults, under-diagnosis by healthcare providers (HCPs), clinical significance of sub-threshold symptoms and under-representation in epidemiological studies of high-risk older adults (e.g. medically ill, LTC residents).3

There are a number of ways in which older adults uniquely express mental health disorders including under-reporting of symptoms, manifesting subclinical disorders and differential expression of symptoms based on age of onset. Clinically significant, subthreshold syndromes increase with age. Psychophysiological changes accompanying normal ageing, including alterations in sleep, appetite and psychomotor functioning, may make it difficult to diagnose clinically significant psychopathology. Cognitive impairment may further cloud the presentation of mood and psychotic symptoms. Late-life mental disorders often vary in their expression (e.g. less endorsement of affective symptoms in mood disorders) and treatment responsiveness (e.g. reduced response to antidepressants). In addition, the co-occurrence of general medical disorders with older age makes attributing functional limitations to mental health diagnoses more difficult. Common mental health problems (e.g. depression) often present atypically (e.g. with memory loss) in older individuals and loss of physical abilities, financial resources and family and friends can challenge even the most resilient amongst older persons. Many mental health problems (e.g. complicated grief) in older adults do not fit the conventional paradigm of disease. Older adults are also more susceptible to the adverse effects of psychotropic drugs. Psychotherapy may need to be modified to accommodate cognitive and sensory deficits. All HCPs working with older adults should be prepared for these challenges.

Laboratory testing, neuropsychological testing and neuroimaging can further assist in accurate diagnosis and identification of prognostic and protective factors in older adults with mental health problems. A comprehensive metabolic panel (CMP), thyroid-stimulating hormone (TSH) and vitamin levels (B12, folate, D) to assess the aetiology of new-onset or resistant mental health problems are recommended. Certain clinical situations may dictate ordering urine tests (analysis, culture and sensitivity) and other laboratory tests (e.g. free testosterone levels in older adults with depression and other symptoms of testosterone deficiency). Before initiating antipsychotics, a baseline electrocardiogram (ECG) is recommended due to recent reports of sudden cardiac death associated with antipsychotic use. For residents in a hospice and for residents in the terminal stages of dementia, these baseline blood tests may not be ordered. Subtle seizure disorder should also be considered in the differential diagnosis of new-onset or atypical mental health syndromes and may require an electroencephalogram (EEG) and a referral to a neurologist. In some situations, a polysomnogram or nocturnal pulse oximetry may need to be ordered to rule out sleep disorders such as obstructive sleep apnoea. Neuropsychological testing is often crucial for accurate early diagnosis of dementing disorders [especially Alzheimer’s disease (AD) and vascular cognitive impairment (VCI)] and differentiating it from depression and mild cognitive impairment (MCI). As part of comprehensive diagnostic work-up, neuroimaging such as computed tomography (CT) or magnetic resonance imaging (MRI) scans is recommended for all older adults with significant cognitive deficits, new onset mood or psychotic symptoms.

Late-life depression is a heterogeneous group of disorders. Late-life depression is prevalent and eminently treatable. Late-onset depression may be a prodrome of late-life dementia and may also promote neuropathogenic processes that eventually cause dementia. Depression has been associated with increased rates of cardiovascular illness and mortality after myocardial infarction. Depression and anxiety typically co-occur. Electroconvulsive therapy (ECT) remains the most effective treatment for depression in older adults. Antidepressants (especially for severe and or chronic depression) combined with psychotherapy is recommended for cognitively intact older adults with depression. Newer brain stimulation therapies (e.g. repetitive transcranial magnetic stimulation, vagal nerve stimulation, magnetic seizure therapy and deep brain stimulation) have not been well studied in older adults with depression and hence their use is not recommended except in academic/research settings.

Bereavement is associated with declines in health, increased utilization of healthcare resources and increased risk of death. Complicated bereavement may be distinct from major depression and formal criteria have been proposed. Complicated bereavement includes symptoms such as extreme levels of ‘traumatic distress’, numbness, feeling that part of oneself has died, assuming symptoms of the deceased, disbelief or bitterness, and symptoms endure for 6 months. Brief dynamic psychotherapy, traumatic grief therapy, crisis intervention and use of support groups can significantly reduce grief symptoms. Antidepressants may also be considered to treat complicated bereavement.

About 1% of the US population above the age of 55 years have severe mental illness (SMI). Mental health disorders considered as SMI include bipolar disorder, schizophrenia and schizoaffective disorder. Cognitive deficits, poor physical health and movement disorders are also experienced by a majority of older adults with SMI and they worsen adaptive functioning. Although suicide remains an important cause of mortality for this population, cardiovascular disease is the leading cause of death. Cardiovascular death among those with SMI is 2–3 times that of the general population. This is in part due to poor access to and use of quality healthcare services and high rates of obesity, diabetes and hyperlipidaemia (often exacerbated by antipsychotics). Older adults with SMI have difficulty complying with care regimens for chronic medical conditions such as diabetes and hypertension and have poor dietary habits. Older adults with SMI commonly face, in addition to persistent symptoms, increasing medical morbidity, limited financial resources and social impoverishment. Among homeless older adults, there is a high prevalence of SMI and cognitive impairment. Poor adherence to medication treatment for both mental and physical health conditions is common in older adults with SMI and has devastating consequences. Adherence problems are complex, determined by multiple factors and thus require a high index of suspicion and customized interventions that are focused on the underlying causes.

When an older adult presents with manic symptoms in later life and has no past history of bipolar disorder, a thorough work-up is recommended to identify general medical conditions that could cause manic symptoms (e.g. right hemisphere stroke, frontotemporal dementia) or drug-induced mania (e.g. corticosteroids or stimulants). Most older adults with bipolar disorder have had the disorder from their young adulthood, although onset as late as in the ninth and tenth decades has been reported. Late-onset bipolar disorder (onset after age 50 years) is commonly associated with comorbidities such as hypertension, diabetes or coronary artery disease and neurological disorders. There is high prevalence of cognitive dysfunction (especially executive dysfunction), frequent abnormalities on structural neuroimaging (e.g. cerebral white matter hyperintensities) and association with stroke. It is less likely to be associated with a family history of mood disorders. Older manic patients seldom display racing thoughts or euphoric/elated mood characteristic of younger adults and are more likely to be irritable, argumentative, angry, paranoid and disorganized. Mixed states are more common than in the younger population and psychotic symptoms are less common. Older adults often have more frequent episodes of mania and depression, with a shorter (e.g. rapid cycling) duration of symptoms than younger patients. Pharmacological interventions (e.g. atypical antipsychotics, valproate) combined with psychosocial interventions (e.g. psychotherapy, family and patient education) are needed for successful outcomes. ECT should not be considered only as a last treatment option, but should be considered in all older adults with bipolar disorder (including those with mild to moderate symptom severity), especially in those with a history of previous good response to ECT.

Schizophrenia is less prevalent than dementias and depression in older adults. However, the total health expenditures for older adults with schizophrenia exceed those of older adults with dementia and depression. Onset of illness is typically in early adulthood, with a small but distinct subgroup developing disease after the age of 45 years. Late-onset schizophrenia has a higher prevalence of the paranoid type, less severe negative symptoms, over-representation of women and requires lower doses of antipsychotic medications compared with early-onset schizophrenia. Most of the older adults with schizophrenia have been active smokers for many years. Older adults with schizophrenia have a high prevalence of vascular risk factors (e.g. obesity, hypertension, diabetes, high cholesterol) and vascular disease (e.g. coronary artery disease). Therefore, treatment interventions should include efforts to control these risk factors optimally. Most older adults with schizophrenia live in the community, are stable, but remain symptomatic and functionally impaired. Sustained remissions, although uncommon, can occur even in older adults with chronic schizophrenia. Pharmacological interventions (primarily atypical antipsychotics) combined with interventions for psychosocial rehabilitation (such as social skills training, cognitive remediation, supported employment, residential alternatives) is often necessary for optimal outcomes. Assertive community treatment and case management greatly increase the success of these interventions.

There is an increased incidence of psychotic symptoms (delusions and hallucinations) in older adults in contrast to younger adults. Older adults presenting with psychotic symptoms for the first time need a thorough evaluation to identify underlying causes such as dementia, delirium, depression, general medical conditions (e.g. cancer) or drug-induced psychoses. If the work-up is negative, a diagnosis of late-onset schizophrenia or delusional disorder may be entertained.

These primarily include dementing disorders, delirium, cognitive impairment no dementia (CIND), mild cognitive impairment (MCI) and vascular cognitive impairment (VCI).

Dementing Disorders

It is important to evaluate formally and diagnose specifically the type(s) of dementia. Comorbid physical and mental health conditions (e.g. nutritional deficiencies, depression) that may accelerate cognitive and functional decline should be looked for and promptly treated. There exists a minimal set of care principles for patients with AD and their caregivers that all clinicians are recommended to follow.17 The goals of care are (1) to delay disease progression, (2) delay functional decline, (3) improve quality of life, (4) support dignity, (5) control symptoms and (6) provide comfort at all stages of dementia. Older adults with dementia-related symptoms of agitation and aggression should first be managed with psychosocial/environmental interventions. Pharmacological interventions (including antipsychotics) should be used only when psychosocial and environmental interventions have failed to control behavioural disruption adequately.18 The findings related to antipsychotic drug safety (e.g. increased risk of mortality and stroke) should be taken seriously by clinicians in assessing the potential risks and benefits of treatment and in advising families about treatment. Better matching of the available psychosocial/environmental interventions to the patient’s strengths and interests may not only reduce agitation but also prevent agitation and depression in persons with dementia.

Delirium