Are you depressed, or do you just feel depressed because of untreated sleep apnea?
What does depression have to do with sleep apnea? A new research study suggests that if you have sleep apnea and you feel depressed, treatment of your apnea with CPAP (Continuous Positive Airway Pressure) might relieve the depression.
Although we don't know how apnea might cause symptoms of depression, or just how CPAP treatment can relieve those symptoms, we have long suspected there is a link. Writing with T. Scott Johnson, MD., we pointed out in Phantom of the Night (1994) that some of the symptoms of depression are commonly seen in people with sleep apnea, and that in many people, these symptoms resolve with CPAP treatment. We included depression as one of the symptoms of apnea in our quiz intended to help people identify apnea. And, based on personal experience and the clinical experience of pyschologists and physicians, I wrote about the importance of being aware that some of the symptoms of sleep apnea could be confused with those of depression; and the importance of having a mental health professional involved in diagnosing and treating apnea, as well as the benefits of CPAP for mood as well as fatigue.
Gila Lindsley, PhD, a psychologist with extensive experience in the diagnosis and treatment of sleep disorders, suggests that people with untreated apnea don't function well and thus experience stress, which in turn can cause a "reactive" depression. Treating the apnea can thus treat the apnea-induced depression.
But "knowing" something from observation or experience is not proving it--so it is good to find a scientific study that strongly supports the idea that CPAP therapy relieves the symptoms of depression--or more precisely, that people with depression and apnea are less depressed if they use CPAP to treat the apnea.
The authors of this new study, Daniel J Schwartz and Gillian Karatinos, are physicians at the Sleep Center at University Community Hospital in Tampa, Florida. They found that a large percentage of the patients coming to them for evaluation of possible apnea had been prescribed antidepressant medications, and many patients showed mild to severe depression on a standard screening test.
In order to see if treating the apnea might relieve the symptoms of depression, they studied a group of patients who had moderate to severe apnea and who responded well to CPAP therapy--the treatment worked for them. The authors evaluated depression using a standard questionnaire before treatment, several weeks after CPAP treatment began, and a year or so later. Only the patients who continued to use CPAP for several hours a night were included in the study results.
The evaluation of depression was based on patient responses to a standard questionnaire instrument, the Beck Depression Inventory (BDI). This test asks patients to score their responses to seven topics that correlate with depression. The topics include: feelings of sadness; pessimism about the future; being overly self-critical; feelings of failure; inability to feel pleasure; suicidal ideation. The patient's scores for each topic are added together for a global score on depression. Schwartz and Karatinos found that the depression scores were lowered for apnea patients treated with CPAP, both in the short term and over a year.
Schwartz and Karatinos are careful to note what is not known or proven. We really don't know if CPAP treatment causes the improvement in depression ratings; there is an association. We don't know if the measured symptoms are caused by "depression" or by sleep apnea. We don't know how apnea might cause the symptoms nor how the treatment might relieve them. But there is a measureable improvement in depression when the apnea is treated.
Take away: If people with symptoms of depression and who have sleep apnea use CPAP, they are likely to have a reduced level of depression. This is a good reason for people living with sleep apnea to use their CPAP treatment faithfully.
Depression can be a serious problem, whatever the cause, but it can be treated. Neither depression nor apnea should be ignored. If people living with apnea continue to feel depressed despite CPAP treatment, they should have their apnea treatment checked and consult a mental health professional.
Schwartz, DJ; Karatinos G. "For individuals with obstructive sleep apnea, institution of cpap therapy is associated with an amelioration of symptoms of depression which is sustained long term." Journal of Clinical Sleep Medicine, Vol.3, No 6, 2007.
Jerry Halberstadt, Sleep apnea can cause depression (1994)
Quiz to identify sleep apnea syndrome
T. Scott Johnson MD, William Broughton, MD, and Jerry Halberstadt; with contributions by B. Gail Demko, D.M.D. Sleep Apnea--the Phantom of the Night 2003 http://www.healthyresources.com/sleep/apnea/phantom/