Little is known regarding the manifestation of symptoms of ADHD in older age and the difficulties these older adults face. Older adults with ADHD are more often divorced and report more loneliness than older adults without this disorder, which suggests loneliness in older age may be more pressing for the older ADHD population.17 ADHD in older adults has also been associated with poor quality-of-life measures, including moderate to severe problems in mobility, self-care, usual activity, pain/discomfort, and anxiety/depression (Table 114,17).
Qualitative research has described a domino effect of a lifetime of living with ADHD. In one American study, older adults with ADHD (N = 24, age 60 to 74) reported experiencing a tangible, accumulated impact from ADHD on their finances and long-term relationships with family, friends, and coworkers.13 Another study utilizing the Dutch LASA data examined how ADHD may impact patient’s lives among participants who were unaware of their diagnosis.18 One-half of patients reported low self-esteem, overstepping boundaries, and feeling different from others. When compared to younger adults with ADHD, older adults report significantly greater impairments in productivity and a worse life outlook.19
Differential diagnosis
When assessing whether an older adult has ADHD, it is important to consider other potential causes of their symptoms (Table 211,15,20-23). The differential diagnosis includes impaired vision and hearing as well as medical illness (vitamin B12 deficiency, hyperthyroidism, hypothyroidism, hyperparathyroidism, and infectious diseases such as herpes simplex virus or syphilis).11,15,20-23 Neurological causes include brain tumors, traumatic brain injuries, postconcussive syndrome, stroke, and neurocognitive disorders.11,15,20-23 Other potential causes include obstructive sleep apnea, mood disorders, substance use disorders, and medication adverse effects (especially with polypharmacy).11,15,20-23 In this population, other causes are often responsible for “late-manifestation ADHD symptoms.”1,15 Neurocognitive disorders and other psychiatric conditions are especially difficult to differentiate from ADHD.
In older adults, ADHD symptoms include frontal-executive impairments, inattentiveness, difficulty with organization or multitasking, forgetfulness, and challenges involving activities of daily living or socialization that can appear to be a mild or major neurocognitive disorder (Table 311,24,25). This includes major neurocognitive disorder due to Alzheimer’s disease, Lewy body disease, and vascular disease.2,26 However, frontotemporal lobar degeneration is reported to have more symptom overlap with ADHD.21,22,26,27 A way to differentiate between neurocognitive disorders and ADHD in older adults is to consider that patients with neurocognitive disorders often progress to visual hallucinations and more extreme personality changes than would be expected in ADHD.11 Each disease also has its own identifiable characteristics. Extreme changes in memory are often Alzheimer’s disease, personality changes suggest frontotemporal lobar degeneration, stepwise decline is classic for vascular disease, and parkinsonian features may indicate dementia with Lewy bodies.21 In addition, the onset of ADHD usually occurs in childhood and can be traced throughout the lifespan,2 whereas neurocognitive diseases usually appear for the first time in later life.2,28 There are nuances in the nature of forgetfulness that can distinguish ADHD from neurocognitive disorders. For instance, the forgetfulness in early-onset Alzheimer’s disease involves “the lack of episodic memories,” while in contrast ADHD is thought to be “forgetfulness due to inadvertence.”11 Furthermore, patients with neurocognitive disorders are reported to have more severe symptoms and an inability to explain why, whereas those with ADHD have a steady level of symptoms and can provide a more comprehensive story.24 Two recent studies have shown that weak performance on language tests is more indicative of a neurodegenerative process than of ADHD.29,30 Research has suggested that if an older adult shows a sudden, acute onset of ADHD-like symptoms, this is most likely reflective of cognitive decline or a mood disorder such as depression.2,15,24
Several other psychiatric conditions share many symptoms with ADHD. Overlapping symptomology between ADHD and mood and anxiety disorders presents challenges.27 Emotional dysregulation is a feature of adult ADHD, and this often causes a mood disorder to be diagnosed without considering other possible explanations.21,22,27,31-34 Features of mania can overlap with ADHD symptoms, including psychomotor agitation, talkativeness, and distractibility.27 Several other disorders also include distractibility, such as depression, anxiety, and substance use disorders.35 Depression and anxiety can be an outcome of untreated ADHD, or can co-occur with ADHD.21-23,27 ADHD can also co-occur with bipolar disorder (BD), substance use disorders, and personality disorders (borderline and antisocial personality disorder) (Figure 121-23,27,35). One suggested method of establishing an appropriate diagnosis is to study the efficacy of the treatment retrospectively. For example, if a patient is presumed to have depression and they do not respond to several selective serotonin reuptake inhibitors, this may be undetected ADHD.27 In addition, the argument about the chronicity of the symptoms should also be considered. ADHD symptoms are pervasive whereas BD symptoms are episodic.35 Depression can be chronic; however, there are often discrete major depressive episodes. It is important to have a clear timeline of the patient’s symptoms. Ask about age of onset, because in theory, ADHD is supposed to start in childhood.22 It is sometimes difficult to ascertain this information because many older adults grew up during a time where ADHD was not a recognized diagnosis.21
Continue to: Diagnosis and workup