CHAPTER
3
The Diagnostic Ds
The Building Blocks for Diagnosing Mental Health Disorders in Older Adults
EXPLAINING an older person’s mental distress as a single mental disorder is often challenging. Of course, simple is better; it is ideal to unify every symptom under a single diagnosis. However, a single diagnosis can be too simplistic; if you do not diagnose each medical and mental disorder a person is experiencing, you may misunderstand the nature of her distress, and your subsequent treatment will miss the mark. For example, if you neglect a patient’s narcissistic character traits or her food insecurity, treating her depressive episode will prove challenging.
The key to diagnosing a patient with a complex presentation is to be open to possibilities. Start with the common disorders while keeping others in mind. In this chapter, we demonstrate, using three case examples, how you can focus on various clinical presentations of the diagnostic Ds—the six common disorders among older adults—while remembering alternative diagnoses. Understanding these six common disorders is critical because they represent the majority of mental health diagnoses in older adults.
THE SIX DIAGNOSTIC DS
Delirium—an acute disturbance in attention and cognition
Drugs—prescribed medications, over-the-counter medications, illicit substances, alcohol, herbal medications, or supplements that may cause or exacerbate mental disorders
Diseases of medical or neurological origin—conditions that may explain or exacerbate mental disorders
Disrupted sleep—disturbances of the ability to initiate and maintain sleep and wakefulness
Depressive disorders—disturbances of mood
Dementia and other neurocognitive disorders—progressive cognitive deficits that degrade a person’s independence
We typically start by considering delirium because it is both the most inclusive and the most reversible disorder. We work down the list step by step to the final D, dementia and other major neurocognitive disorders, the least reversible disorders. Along the way, we try to avoid these common errors:
- Diagnosing an irreversible disorder, such as Alzheimer’s disease, when a patient actually has a potentially reversible condition, such as mild neurocognitive disorder due to benzodiazepine use
- Failure to diagnose a new-onset medical or neurological disorder that is comorbid with psychiatric disorders, such as when a patient has previously undiagnosed Parkinson’s disease and presents with cognitive impairment and depression
- Making multiple diagnoses when a single one better explains all symptoms, such as when a hospitalized patient exhibiting sudden-onset mood, cognitive, and psychotic problems is diagnosed with Alzheimer’s disease and major depressive disorder with psychotic features instead of with delirium
Delirium
Three years ago, Anni, a 75-year-old woman, was diagnosed with mild memory problems. Two weeks ago, she was hospitalized with pneumonia. She became confused and agitated, and although she was calmed by high doses of lorazepam and olanzapine, she rarely knew the year and could not recognize her husband, Matias. He brings her to your clinic for a post-hospitalization visit. He is concerned that Anni remains confused and wonders whether she developed dementia while hospitalized.
During your interview, you observe that Anni seems slightly drowsy but is awake throughout. She is oriented to herself and her husband but thinks the year is 1952 and she is back in her childhood home. Anni is not able to complete the tapping A task from the Montreal Cognitive Assessment (MoCA) successfully, stopping halfway through because she forgot what the task was. You administer a Short Confusion Assessment Method (Short CAM), a brief diagnostic test for delirium. The Short CAM confirms your concern that Anni is still lethargic and has delirium. Your repeat medical workup for an infection is negative. You reassure Matias that Anni has delirium that needs to resolve and provide him with tips to manage Anni’s delirium at home. You teach Matias that until Anni’s delirium resolves, you cannot comment on whether Anni has dementia.
When a patient presents with cognitive impairment, we first evaluate for delirium (Box 3–1), a reversible cause of cognitive impairment and a medical emergency that carries a high risk of mortality if left untreated. Delirium can take days to months to completely resolve. Older adults, especially those who had mild or major neurocognitive disorder prior to the episode of delirium, may not return to their baseline cognition and therefore will have a new cognitive baseline (Inouye 2006). The CAM is a brief questionnaire, available in 4-item and 10-item versions, that can be helpful for the detection of delirium (Inouye et al. 1990).
Drugs
You reassure Matias that Anni’s delirium will likely improve. Indeed, 2 weeks later, Anni recognizes her husband and knows the year. She is frustrated, however, because poor concentration and lethargy prevent her from pursuing favorite hobbies such as reading and knitting. You review Anni’s medication list, which includes the following prescriptions, some of which were prescribed by her previous primary care practitioner and the hospital physicians: cyclobenzaprine and tramadol for chronic pain, over-the-counter Tylenol PM and temazepam for sleep, clonazepam for anxiety, and diphenhydramine for seasonal allergies, plus olanzapine and as-needed lorazepam for agitation.
Concerned that the many different drugs Anni is taking may be contributing to her cognitive impairment, you initially stop the as-needed lorazepam because benzodiazepines are known to worsen delirium. Then you taper the olanzapine and switch her diphenhydramine to nasal saline and fluticasone sprays because both olanzapine and diphenhydramine are centrally acting. After repeated psychoeducation over three visits about how her pain medications, hypnotics, and benzodiazepines are contributing to her cognitive impairment, Anni agrees to pursue cognitive-behavioral therapy (CBT) for pain and anxiety in order to eventually stop cyclobenzaprine, tramadol, Tylenol PM, and benzodiazepines. She also agrees to stop drinking two glasses of wine every night. Three months after you first see her, Anni is taking only clonazepam and temazepam and reports that she is now able to knit some simple patterns again.
Drugs, whether prescribed medications, over-the-counter medications, alcohol, or illicit substances, are potentially reversible causes of cognitive impairment. Classes of prescribed medications that commonly contribute to cognitive impairment include pain medications (particularly opioids and those with anticholinergic properties), benzodiazepines, anticholinergics, antihistamines (including those sold over the counter), and sedative-hypnotics. Practitioners should also ask patients about use of alcohol, marijuana, illicit drugs, herbal medications, supplements, and over-the-counter medications, all of which can contribute to cognitive impairment. In Anni’s case, multiple drugs are contributing to her cognitive impairment, so her DSM-5 diagnosis (American Psychiatric Association 2013) is mild neurocognitive disorder secondary to substance/medication use.
Diseases of Medical or Neurological Origin
During your medical review of Anni’s systems, she reports frequent tremors and inconsistent use of her continuous positive airway pressure (CPAP) machine. You are concerned about Parkinson’s disease because her tremor has persisted despite stopping the olanzapine, and you refer her to a specialist in movement disorders for evaluation. He diagnoses essential tremor rather than Parkinson’s disease and prescribes propranolol. You refer Anni to a primary care psychologist to improve her compliance with the CPAP. Over the next 2 months, Anni’s CPAP compliance improves from 37% to 84%. She reports decreased lethargy and improved concentration, although she continues to take daytime naps for 1–2 hours each day and still struggles to use more complex knitting patterns.
Medical and neurological disorders other than delirium and major neurocognitive disorder are common causes of cognitive impairment. DSM-5 lists various causes of neurocognitive disorders, including those that affect the brain, such as stroke, traumatic brain injury, Parkinson’s disease, and Huntington’s disease. Other important conditions to investigate and manage are those that are potentially reversible, including obstructive sleep apnea (OSA), vitamin B12 deficiency, and hypothyroidism. Untreated sleep apnea can lead to attentional difficulties and daytime somnolence that cause significant underperformance on cognitive screening, which then can result in the misdiagnosis of dementia. In Anni’s case, we first excluded Parkinson’s disease, a potential neurological cause that might have explained her cognitive symptoms, and also looked for a medical problem (OSA) that explained or exacerbated her cognitive problems. Her DSM-5 diagnosis is mild neurocognitive disorder secondary to medical disorder.
Dementia and Other Neurocognitive Disorders
MILD NEUROCOGNITIVE DISORDER
You successfully taper off Anni’s temazepam, but as you begin tapering off her clonazepam, she complains of worsening anxiety and feeling “blue.” She confesses concern that she is developing dementia because she continues to struggle with favorite activities and paying the bills. She says, “I don’t remember what I did more than 5 minutes ago.” She remains housebound because of chronic pain. As you problem solve, Anni eventually agrees to a trial of venlafaxine to treat her depression, anxiety, and pain. She also attends booster CBT sessions for anxiety. After 2 months of combined treatment with an antidepressant and CBT, Anni returns “mostly to the way I was before I was in the hospital.” On the Patient Health Questionnaire 9-item depression scale (PHQ-9), Anni’s score is 2, which is consistent with the absence of depressive symptoms. She is able to pursue most activities without difficulty, although she notes intermittent difficulty with word finding and recalling details of recent events a few weeks later. Her MoCA score is 24/30. She loses points in the domains of attention, word fluency, and delayed recall; however, these stable deficits appear mild and do not affect her functioning significantly, as she is able to compensate by making checklists and programming reminders into her cell phone. Now that you have optimized her medication regimen and addressed the medical and mental health issues contributing to her cognitive impairment, you tentatively diagnose Anni with mild neurocognitive disorder and refer her for detailed neuropsychological evaluation to make sure she does not have dementia (major neurocognitive disorder). The geriatric neuropsychologist confirms your diagnosis because Anni performs 1–2 standard deviations below the mean in the domains of memory and executive functioning.
Depressive disorders, ranging from depressive episode with insufficient symptoms to major depressive disorder, are often accompanied by subjective cognitive complaints. In some cases, the cognitive deficits will resolve, but in others they will persist. The cognitive impairment can range from mild difficulty paying attention to an inability to complete complex activities or to a dementia-like picture historically referred to as pseudodementia. Practitioners should suspect depression as a significant cause of cognitive impairment when patients’ cognitive complaints are significantly worse than their cognitive and functional performance on objective measures.
Depression should be aggressively treated both because it is an independent risk factor for dementia (Byers and Yaffe 2011) and because its presence can compromise an accurate diagnosis of a neurocognitive disorder. In Anni’s case, her depressive symptoms were aggressively treated before she was referred for neuropsychological evaluation and diagnosed with mild neurocognitive disorder (Box 3–2) due to Alzheimer’s disease. However, patients with atypical presentation and/or failure to respond to multiple trials of antidepressants should be referred for neuropsychological evaluation because behavioral symptoms can be the presenting feature of atypical major neurocognitive disorders such as those due to frontotemporal dementia (Lanata and Miller 2016).