Mood disorders spell danger for patients with chronic obstructive pulmonary disease (COPD). Comorbid depression and anxiety often complicate or frustrate treatment of this debilitating—and ultimately fatal—respiratory disease (Box 1).
Managing COPD-related psychiatric disorders is crucial to improving patients’ quality of life. This article presents two cases to address:
- common causes of psychiatric symptoms in patients with COPD
- strategies for effectively treating these symptoms while avoiding adverse effects and drug-drug interactions.
CASE REPORT: COPD AND DEPRESSION
Ms. H, age 59, a pack-a-day smoker since age 19, was diagnosed with COPD 3 years ago. Since then, dyspnea has rendered her unable to work, play with her grandchildren, or walk her dog. She has become increasingly apathetic and tired and is not complying with her prescribed pulmonary rehabilitation. Her primary care physician suspects she is depressed and refers her to a psychiatrist.
COPD: debilitating and progressive
COPD is the fourth leading cause of death in the United States after heart disease, malignant neoplasms, and cerebrovascular disease. A total of 122,009 COPD-related deaths were reported in 2000.1
Cigarette smoking causes 80 to 90% of COPD cases.2 Occupational exposure to particles of silica, coal dust, and asbestos also can play a significant role. Alpha-1-antitrypsin deficiency—a rare, genetically transmitted enzyme deficiency—accounts for 0.1% of total cases.
Two disease processes are present in most COPD cases:
- emphysema, resulting from destruction of air spaces and their associated pulmonary capillaries (Figure)
- chronic bronchitis, causing airway hyperreactivity and increased mucus production.
The first symptom of COPD may be a chronic, productive cough. As the disease progresses, the patient becomes more prone to pulmonary infections, increasingly dyspneic, and unable to exercise. This results in occupational disability, social withdrawal, decreased mobility, and difficulty performing activities of daily living. Initially, an increased respiratory rate keeps oxygen saturation normal. Over time, however, the disease progresses to chronic hypoxia.
End-stage COPD is characterized by chronic hypoxia and retention of carbon dioxide due to inadequate gas exchange. Death results from respiratory failure or from complications such as infections.
During the psychiatrist’s initial interview, Ms. H exhibits anhedonia, feelings of worthlessness and hopelessness, and low energy. She also reports poor sleep and appetite. Her Beck Depression Inventory score of 30 indicates severe major depression.
She is taking inhaled albuterol and ipratropium, 2 puffs each every 6 hours, and has been taking oral prednisone, 10 mg/d, for 5 years. The psychiatrist adds sertraline, 50 mg/d. Her mood, anhedonia, and subjective energy level improve across 2 months. Her Beck Depression Inventory score improves to 6, but her positive responses indicate continued poor appetite, lack of sex drive, and low energy. She often becomes breathless when she tries to eat. Her body mass index is 18, indicating that she is underweight. Caloric nutritional supplements are initiated tid to increase her weight. Her sertraline dose is continued.
Approximately 1 month later, Ms. H is able to begin a pulmonary rehabilitation program, which includes:
- prescribed exercise to increase her endurance during physical activity
- breathing exercises to decrease her breathlessness.
Ms. H also begins attending a support group for patients with COPD.
After 12 weeks of pulmonary rehabilitation, Ms. H is once again able to walk her dog. The psychiatrist continues sertraline, 50 mg/d, because of her high risk of depression recurrence. She continues to smoke despite repeated counseling.
Discussion. This case illustrates how progressing COPD symptoms can compromise a patient’s ability to work, socialize, and enjoy life. The resulting social isolation and loss of independence and self-esteem can lead to depression.3
Forty to 50% of patients with COPD are believed to have comorbid depression compared with 13% of total patients.4 Small sample sizes have limited many prevalence studies, however.4-6
Long-term corticosteroid therapy may also have fueled Ms. H’s depression. Prednisone is associated with dose-related side effects, including depression, anxiety, mania, irritability, and delirium.7
Ms. H’s case also illustrates how depression can derail COPD treatment and predict poorer outcomes of medical treatment in COPD patients.8 Fatigue, apathy, and hopelessness kept her from following her pulmonary rehabilitation regimen.
Treatment. Selective serotonin reuptake inhibitors (SSRIs) are considered first-line treatment for comorbid depressive or anxiety disorders in patients with COPD. These agents are associated with a relatively low incidence of:
- anticholinergic and other side effects
- interactions with other drugs commonly used by COPD patients.
Sertraline, citalopram, and escitalopram have fewer side effects and affect the cytochrome P (CYP)-450 pathway to a lesser degree than do other SSRIs.
Venlafaxine, a serotonin-norepinephrine reuptake inhibitor, is another first-line option. This agent is associated with dose-dependent increases in blood pressure, so use it with caution in hypertensive patients.