Fig. 4.1
Possible mechanisms for anxiety in COPD. IRV inspiratory reserve volume. Medications for COPD implicated in anxiety include steroids and beta agonists
The carbon dioxide sensitivity model postulates that central chemoreceptor hypersensitivity to CO2, in the respiratory center of the brainstem, trigger anxiety symptoms, and panic attacks (“false suffocation alarm”) [23]. This is an attractive hypothesis for panic attacks esp. in the subset of COPD patients (previously known as “blue bloaters”) who are predisposed to CO2 retention.
The hyperventilation model hypothesizes that an abnormal breathing pattern in COPD leads to dyspnea and anxiety [24]. The ensuing hypocapnia (from hyperventilation) accentuates feelings of both anxiety and breathlessness, resulting in a vicious cycle. The dyspnea-anxiety-dyspnea model proposes a similar mechanism where dyspnea—one of the cardinal features of COPD—and anxiety feed into each other [25].
The cognitive behavioral model is based on a similar premise: COPD patients misperceive their physical symptoms particularly that of breathlessness, leading to heightened awareness of arousal and exacerbation of anxiety and panic [24].
Lastly, the biological model suggests that anxiety itself causes hyperventilation and bronchoconstriction thereby worsening COPD symptoms [26].
Dyspnea appears to be the major mechanistic link between COPD and anxiety disorders. However, the severity of dyspnea does not always correlate with the severity of anxiety symptoms [27]; neither does effective treatment of dyspnea—through pharmacological or rehabilitative means—always lead to amelioration of anxiety. This suggests that other factors also play a role in pathogenesis. One such factor could be the medications used for COPD treatment themselves, as anxiety and panic attacks could be related to beta agonist and high dose steroid therapy used in selected patients [28].
Depression
Various psychological and biological theories have been suggested for increased rates of depression in COPD (Fig. 4.2).
Fig. 4.2
Possible mechanisms for depression in COPD
Firstly, COPD leads to immense fatigue and impaired mobility. These precipitate a deterioration in functional independence, as well as social and occupational decline [17]. Such handicap can cause or exaggerate feelings of depression.
Secondly, increased hypoxia in the middle-aged COPD patient population (both from the disease and smoking) leads to increased rates of depression at an older age. Persistent hypoxia in the brain can cause white matter and endothelial changes, and oxidative stress. This can result in mood changes and a decline in executive functioning, depending on the affected area of the brain [4].
Thirdly, a chronic systemic inflammatory state associated with COPD (with elevated C-reactive protein and cytokine levels) has also been proposed as a cause for increased rates of depression [4].
Lastly, the medications used to treat COPD can themselves precipitate or worsen mood disorders. In one study, patients with severe COPD who were receiving steroids had higher rates of depression when compared to those not on the medication [29].
Clinical Features and Implications of Psychological Disorders in COPD
There is a considerable overlap between symptoms due to COPD and those from anxiety and depression; a careful evaluation is hence necessary prior to diagnosing a psychiatric disorder in this population. Comorbid anxiety and depression adversely affect COPD patients. Longer hospital stays and impaired ambulation, mobility, sleep, and rest have been observed in COPD patients with psychiatric disorders than those without [30, 31].
Anxiety
Feelings of difficult to control anxiety and apprehension, coupled with psychosomatic complains (increased muscle tension, restlessness, sleep difficulties, fatigue, difficulty in concentration, and irritability) occur with generalized anxiety disorder. Recurrent panic attacks (acute onset, short-lived episodes with characteristic symptoms and signs of autonomic arousal and feelings of doom) are a feature of panic disorder.
Anxiety symptoms significantly impact the quality of life in COPD patients. Higher rates of hospitalization, longer length of inpatient stay, impaired physical and social functioning (with increased social isolation), and quality of life are linked with the disorder in this population [6, 32, 33]. One study suggests that, at least in females with COPD, poor emotional function may be a predictor of overall poor survival [34].
Depression
Low moods or loss of interest in previously pleasurable activities are the hallmark of depression. Other symptoms include disturbances in sleep and appetite, feelings of guilt or hopelessness, psychomotor retardation or agitation, fatigue, impaired concentration, and suicidal ideation.
Depression is a better predictor of functional capacity as compared to physiological parameters in patients with COPD [17]. It leads to an increased frequency and length of stay in hospitalized COPD patients and increases utilization of outpatient and emergency care [35]. Ultimate medical costs for such patients rise by 50% [36]. Other than impacting the financial cost for COPD sufferers, it also detrimentally affects their quality of life, due to further impairment in social and occupational functioning.
Depression also acts as a barrier to seeking help and thus leads to worsening of the primary symptoms of COPD due to inadequate treatment. This in turn results in an exaggeration of the mood symptoms, hence, initiating a vicious cycle of deterioration.
Screening and Diagnosis
Accurate diagnosis of psychiatric illnesses starts with having a high index of suspicion for the ailments. Clinicians and healthcare workers involved in managing COPD patients should be cognizant of the high frequency of psychological disease in COPD. Patients should be referred to qualified mental health professionals when there is concern for mental illness. Screening tools serve as a useful aid in identifying such individuals. Diagnosis is made using DSM-V criteria.
Anxiety Disorders
Screening: Anxiety specific as well as global psychological assessment tools with anxiety domains are available for screening for anxiety disorders. Anxiety-specific questionnaires include the Beck Anxiety Inventory, State-Trait Anxiety Inventory, and Hamilton Anxiety Rating Scale [37, 38]. Global psychological assessment tools include the Hospital Anxiety and Depression Scale, Hopkins Symptom Check List, and Patient Health Questionnaire [39, 40].
A simple 5 question-based tool, Primary Care Evaluation of Mental Disorders (PRIME-MD), appears to be quite useful in identifying patients at risk for psychological disorders (Table 4.1) [41]. Scores above specified cut off points on these tools indicate need for further evaluation of patients; they should be referred to qualified mental health specialists.
Table 4.1
PRIME-MD screening questionnaire for depression and anxietya
Depression screen (PHQ-2) | In the past month, have you been bothered a lot by: 1. Little interest or pleasure in doing things? 2. Feeling down, depressed or hopeless? |
Anxiety screen (PHQ-3) | In the past month, have you been bothered a lot by: 1. “Nerves,” or feeling anxious or on edge? 2. Worrying about a lot of different things? During the last month: 3. Have you had an anxiety attack (suddenly feeling fear or panic)? |
Diagnosis: Specific diagnosis of anxiety disorders should be made by a psychiatrist, using DSM criteria (Tables 4.2 and 4.3). As mentioned earlier, there is a considerable overlap between symptoms of anxiety and those of COPD. A detailed, structured interview by a mental health professional helps differentiate symptoms due to anxiety disorders from those of the underlying COPD.
Table 4.2
Generalized anxiety disorder
Generalized anxiety disorder |
– Anxiety and apprehension about different personal, social or occupational circumstances – Feelings of worry are out of proportion to expected norms – Symptoms are present for the majority of a minimum six month period – Symptoms include at least three of: excessive muscle tension or strain, easy fatigability, sleep disturbances/insomnia, difficulty with maintaining concentration, feelings of unease or restlessness, and irritability – Symptoms significantly affect the ability to perform well (at work, in a social setting, etc.) or result in suffering – Symptoms are not otherwise explained or caused by a medical condition, medication or drug of abuse, or by a mental condition other than generalized anxiety disorder |
Table 4.3
Panic disorder
• Characteristic, repeated, panic attacks – Sudden feeling of intense debilitating fear and anxiety, in the absence of an obvious cause or danger. Symptoms peak within a few minutes and should include at least four of the following: feeling of doom/fear of death, palpitations, dyspnea, chest pain, sweating, shaking/trembling, choking sensation, nausea or abdominal discomfort, feeling of numbness/tingling, light-headedness/dizziness, depersonalization (feeling detached from one’s body) or derealization (feeling detached from reality) |
• Significant anxiety about the possibility of a recurrence of a panic attack for at least a one month period after one such episode. This anxiety can lead to avoidance behavior (typically, with the goal of not triggering further panic attacks) resulting in functional impairment • Symptoms are not otherwise explained or caused by a medical condition, medication or drug of abuse, or by a mental condition other than panic disorder |
Depression
Screening: Screening tools can help identify COPD patients at risk for major depressive disorder. Several questionnaires are available, including the Beck Depression Inventrory, Zung Depression Scale, the Patient Health Questionnaire-9 (PHQ-9), the Center for Epidemiologic Studies-Depression (CES-D) scale, Geriatric Depression Scale, and Brief Depression Scale, all with reasonable sensitivity and specificity [42–47]. As mentioned above, a simple, 5 question instrument, PRIME-MD, is a good screening tool for depression and anxiety in this population [41].
Screening tools can aid physicians in identifying vulnerable patients. These patients should then be referred to a psychiatrist.
Diagnosis: A firm diagnosis of depression in COPD is based on a clinical interview by a psychiatrist. DSM-V and the ICD 10 are common criteria used for diagnosis (Table 4.4). Neurovegetative signs such as sleep, fatigue, and appetite problems can be misleading in identifying depression in COPD as these can be related to the primary disease itself. Loss of interest and enjoyment in pleasurable activities (anhedonia), feelings of guilt and hopelessness, and suicidal ideations, along with depressed mood, can be better indicators of depression in this population [17].
Table 4.4
Major depressive disorder
– Low mood and/or anhedonia associated with at least threea (or more) of: sleep disturbances (insomnia or hypersomnia), fatigue/low energy, feelings of guilt or low self-esteem, significant change in appetite or weight (depressed or excessive), restlessness or lethargy, suicidal ideation or preoccupation with death, or decreased ability to concentrate |
– Symptoms persist for at least a two week duration |
– Absence of manic or hypo-manic episode |
– Symptoms significantly affect the ability to perform well (at work, in a social setting, etc.) or result in suffering |
– Symptoms are not otherwise explained or caused by a medical condition, medication or drug of abuse, or by a mental condition other than major depressive disorder |
Treatment
A multidisciplinary approach—involving the primary care physician and nurse, pulmonary specialist, social worker and physiotherapist (especially those involved in pulmonary rehabilitation), and mental health professionals—is best for COPD patients with psychological disorders, as it focuses on both the patient’s physical and psychological well-being. Pulmonary rehabilitation is an example of such a multidisciplinary collaborative care model and has been shown to improve exercise capacity, dyspnea severity, and health-related quality of life, including emotional function, reduction in anxiety and depression symptoms, and improved cognitive function [27, 48–50].
Clinicians should optimize medical therapy for COPD (bronchodilators, inhaled corticosteroids—when indicated—roflumilast, long-term oxygen therapy, etc.) as improved lung function and functional capacity impact psychological symptoms favorably. Treatment of comorbid mental disease is essential; psychological disorders remain untreated in a significant portion of COPD patients [10, 51].
Psychiatric help is especially useful when psychological symptoms are severe and refractory, there is concern for drug interaction with complex regimen in the elderly, or with suicidal ideation.
Anxiety Disorders
Non-pharmacological Therapy
Mixed results have been observed with psychotherapy for anxiety disorders in COPD [33, 52, 53]. Cognitive behavior therapy aims to correct distorted views about life experiences in COPD patients whereby emotional distress magnifies the physical handicap and symptoms due to the chronic respiratory illness. Progressive muscle relaxation (with or without breathing exercises and disease specific education), attempts to reduce anxiety by decreasing muscle tension. Improvement in anxiety symptoms was observed in a few studies with the above measures; other studies have not demonstrated any conclusive benefit with these therapies [54–56].
Pharmacotherapy
It is important to differentiate between symptoms due to a true anxiety/panic disorder versus panic due to severe dyspnea secondary to exertion in patients with limited functional pulmonary reserve in stage III and stage IV COPD. Medications help for the former, whereas education about recognizing functional limitation and changes in perception (to break the dyspnea-anxiety-dyspnea cycle) may be more useful for the latter.
Very few rigorous, randomized studies have been conducted on medication use for anxiety disorders in COPD. Similar to treatment for anxiety disorders with no comorbids, psychotropic medications—selective serotonin reuptake inhibitors (SSRIs) (Table 4.5), serotonin receptor agonists (buspirone), and tricyclic antidepressants (TCAs)—are used in clinical practice as pharmacotherapy for anxiety in COPD. The serotonergic effect of these medications (well established esp. for clomipramine) potentially decreases central chemoreceptor CO2 sensitivity and ameliorates panic attacks [23]. SSRIs appear to be well tolerated [61, 62]. Data on efficacy, however, is equivocal [63, 64]. Caution should be exercised when using TCAs, especially in the elderly, due to potential cardiac toxicity.
Table 4.5
Commonly used medications for depression and anxiety in COPD
Citalopram | Escitalopram | Fluoxetine | Paroxetine | Sertraline | Buspirone | |
|---|---|---|---|---|---|---|
Usual daily dose (depression) | 20–40 mg | 10–20 mg | 10–20 mg | 20 mg | 50 mg | |
Usual daily dose (anxiety) | N/A | 10–20 mg | 10–20 mg | 20 mg | N/A | 20–30 mg
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