About one in three cases of depressive disorders in the geriatric population have their onset in late life; many more cases are recurrences of depressive disorders which began earlier in life. This chapter reviews the diagnosis and treatment of depressive disorders in late life to facilitate their differentiation from other conditions and recommend non-pharmacological treatment and age-adjusted pharmacological interventions. Both early-onset and late-onset categories may be unreported or missed. Late-life depressive disorders have been under-recognized and inadequately treated in primary care, especially among Hispanic and African American men in the United States (Hasin et al. JAMA Psychiatry 75:336¿46, 2018)). Many factors may account for missed depressive disorders among aging individuals. The geriatric patient may present with more somatic complaints, greater social isolation, and reduced access to medical care (especially for underserved minority populations) and be hesitant to report depressive symptoms. The impact of psychosocial stressors on the patient may not be fully appreciated nor is clinical time often adequate to explore them. The number of systemic medical comorbidities increases with age and correlates with the increased prevalence of depressive disorders as patients age. Teasing out depressive symptoms among somatic complaints in the elderly patient is a challenge. Complex medication regimens, in the context of pharmacodynamic and pharmacokinetic effects of aging, can contribute to an increased risk of adverse effects, which can also contribute to depressive symptoms.

Manic and hypomanic symptoms in late life are, more likely than not, recurrent episodes of bipolar disorder which began early in life. A manic or hypomanic episode which occurs for the first time in late life is often associated with, or due to, systemic medical comorbidity and can be considered secondary mania/hypomania. By similar reasoning, a patient with a pre-existing unipolar depressive disorder which first occurred earlier in life, and who subsequently develops a first manic episode in late life, may be re-diagnosed as bipolar I disorder. One study of a cohort with recurrent unipolar depressive disorders found that at least 1% per year converted to bipolar disorder with a manic episode over the course of their lifetimes, even beyond age 70 (Angst et al., J Affect Disord 84:149¿57, 2005). A detailed history of mood episodes for the geriatric patient and a thorough medical evaluation is therefore essential. This chapter provides an overview of the diagnosis and treatment of bipolar disorder and related disorders in late life. In the aging patient, mania or hypomania can emerge in the context of cognitive deficits, communication difficulties, systemic medical comorbidities, and medication effects, all of which can confound assessment and accurate diagnosis. Conditions which can present with mania or hypomania include behavioral and psychological symptoms of dementia (BPSD) and delirium with symptoms such as apathy, distractibility, labile mood, anxiety, and irritability (Cassel and Fulmer, JAMA 327:919¿920, 2022). The search for causes of secondary manic or hypomanic symptoms which appear in late life can help minimize unnecessary or inappropriate treatment.

Aging adults experience many stressful events, and psychiatric symptoms associated with these events can exert a significant impact (Murayama et al., Geriatr Gerontol Int 20:297¿303, 2020). Loss of loved ones, changes in living situation, impaired mobility, surgery, loss of employment, financial demands, acute medical conditions, and various physical disabilities are common. Psychological and social reserves in the geriatric patient may afford resilience and facilitate successful adaptation (Whitson et al., J Gerontol A Biol Sci Med Sci 71:489¿495, 2016). A thorough history from both the patient and reliable observers who know the patient's baseline can also aid in the early identification of stressors and maladaptive responses. The syndrome of post-traumatic stress disorder (PTSD) although often categorized under anxiety disorders is included here because it is the result of significant stressors which may have occurred earlier in life and may be overlooked in the aging adult (see Fig. 13.1). Symptoms of adjustment disorder, acute stress disorder, posttraumatic stress disorder (PTSD), persistent complex bereavement, and/or bereavement may be overlooked by the busy clinician who must focus on the current medical symptomatology. This chapter provides an overview of stress-related syndromes in the geriatric patient to encourage early recognition and prompt age-adjusted interventions (see Table 13.1).

Nearly all patients with major neurocognitive disorder (MNCD, formerly dementia) or mild neurocognitive disorder (mNCD) will develop non-cognitive neuropsychiatric symptoms (NPS) at some point in the course of their disease. Clinicians of any discipline or medical specialty who treat geriatric patients will inevitably see patients with MNCDs and associated behavioral and psychological symptoms of dementia (BPSD). NPS may present in the prodromal phase of Alzheimer's disease (AD) and other neurodegenerative disorders, and they often increase in frequency throughout the course of the illness. Comorbid depressive and psychotic disorders, among NPS, are associated with more rapid cognitive decline in AD. Given their enormous impact on quality of life, safety, function, caregiver burden, and cost of care, BPSD become the primary concern of family and caregivers. The demand for treatment of BPSD is significant: a cross-sectional analysis of Medicare claims in the United States in 2018 found that 13.9% of older individuals with MNCD filled prescriptions for CNS-active polypharmacy (Maust et al. JAMA 325:952¿61, 2021). This chapter discusses an age-adjusted approach to NPS: ruling out modifiable contributors to MNCDs, treating systemic medical comorbidities, correcting environmental factors, and instituting non-pharmacological interventions as first-line interventions. A minimalist ethic endorses pharmacological treatment when it is needed for the management of disruptive or dangerous psychiatric symptoms but always with the goal of limiting risk of adverse effects.

The enlarging need for clinicians with specialized geriatric expertise in the USA (Institute of Medicine (IOM) 2012; Wiechers et al. 2019) can hopefully be met through telemedicine and digital technologies, supplemented by remote video consultation to home-based and long-term care settings (Gentry MT et al., Am J Geriatr Psychiatry 27:109¿27, 2019). This chapter reviews technologies which may facilitate prompt screening and assessment of older individuals by minimizing the time for a provider to receive clinical information (Fortuna 2019). Frequent subspecialty consultation and remote digital monitoring can foster earlier recognition of emerging psychiatric issues and reduce complications that result from delay of care. Timely review of medication regimens along with de-prescribing can avoid unnecessary or excessive treatment, the essence of an age-adjusted approach. Figure 16.1 summarizes the use of assistive technology in geriatric care, including the role of wearable devices, home monitoring systems, pandemic proof, and remote care and the considerations for telemedicine.