A new study from the University of Western Australia found that more than 70 percent of people with sleep apnea experience symptoms of depression.
Dr. John Suen is the Medical Director of Sleep Disorders Center Florida, an accredited medical treatment center for all sleep-related issues located right here in Vero Beach. He is familiar with the study, and says the results are consistent with previous studies. “Sleep apnea can cause very fragmented sleep and sleep deprivation, and has been linked to psychiatric illness, including depression,” Dr. Suen says. “If we don’t sleep well, our mood is down, and we are less happy.”
The research was published in the Journal of Clinical Sleep Medicine and highlights the importance of evaluating individuals experiencing depression for signs of sleep apnea. Dr. David R. Hillman, clinical professor at the University of Western Australia and one of the researchers, says the findings “highlight the potential for sleep apnea, a notoriously underdiagnosed condition, to be misdiagnosed as depression.”
The link between sleep apnea and depression was underscored by one of the study findings – the greater the severity of sleep apnea, the higher the likelihood of depressive symptoms.
More than 25 million adults in the US have sleep apnea. The most common form is called obstructive sleep apnea; it occurs due to a relaxation of the throat muscles. Dr. Suen says that approximately 95 percent of the cases are of this form; central sleep apnea accounts for the other 5 percent, and occurs when the brain doesn’t send the right signals to the muscles that control breathing.
The symptoms of the two types often overlap, making a specific diagnosis difficult. The most common symptoms include:
Loud snoring, which is usually more prominent in obstructive sleep apnea.
Episodes of breathing cessation during sleep as witnessed by another person.
Abrupt awakenings accompanied by shortness of breath; this more likely indicates central sleep apnea.
Noticeable signs upon awakening, including a dry mouth, sore throat, or headache.
Insomnia, in the form of having trouble staying asleep.
Excessive daytime sleepiness, perhaps with associated attention problems.
It is possible for people to have both forms of apnea; in that case it’s called complex sleep apnea syndrome.
People diagnosed with moderate or severe sleep apnea often benefit from a “continuous positive airway pressure” (CPAP) machine; it delivers air pressure while the person sleeps, through a mask placed over the nose. With CPAP, the air pressure is higher than that of the surrounding air, which keeps the upper airway passages open.
Considering the link between sleep apnea and symptoms of depression, it is not surprising that the Australian researchers found that CPAP was also effective in reducing depressive symptoms. In the study, 293 participants diagnosed with sleep apnea were offered CPAP therapy five hours a night for three months. Of those 293 participants, 213 (73 percent) had symptoms of depression as the study started. At the end of the 3 months, only 4 percent of those participants who complied with the treatment had any significant symptoms of depression.
Dr. Suen says this is consistent with what he sees at his Center.
While sleep apnea can affect anyone, there are certain risk factors. For obstructive sleep apnea, Dr. Suen says the greatest risk factors are:
- Excess weight. People who are obese have four times the risk of sleep apnea compared to people who are a normal weight. Fat deposits around the upper airway may obstruct their breathing.
- Neck circumference. People with thicker necks may have narrower airways. For men, the risk increases if neck circumference is 17 inches (43 centimeters) and larger. In women, the risk increases if neck circumference is 15 inches (38 centimeters) or more.
- Use of alcohol, sedatives or tranquilizers. These substances relax the muscles in the throat and increase the risk.
Other risk factors include:
- A narrowed airway. You may have inherited a naturally narrow throat. Or, tonsils or adenoids may become enlarged and block the airway.
- Being male. Men are twice as likely to have sleep apnea. However, women increase their risk if they’re overweight, and their risk also appears to rise after menopause.
- Being older. Sleep apnea occurs significantly more often in older adults.
- Family history. If you have family members with sleep apnea, you may be at increased risk.
- Smoking. Smokers are three times more likely to have obstructive sleep apnea than are people who’ve never smoked. Smoking may increase the amount of inflammation and fluid retention in the upper airway.
- Nasal congestion. People who have difficulty breathing through their nose – for any reason – are at higher risk.
For the much less common central sleep apnea, the primary risk factors are being older, history of heart disease or stroke, and using narcotic pain medications.
Previous studies link sleep apnea to an increased risk for high blood pressure, heart disease, stroke, and type 2 diabetes; Dr. Suen agrees there is “absolutely” a connection.
Dr. Suen says it’s critical that clinicians ask depressed patients about snoring, disrupted sleep, excessive daytime sleepiness and any other symptoms of sleep apnea – including what their sleep partners have been observing. It may be that sleep apnea – easily treatable with CPAP therapy – is an underlying cause of their depression.
Dr. Suen is board-certified in Sleep Medicine, Pulmonary Disease, Internal Medicine, and Critical Care Medicine. Sleep Disorders Center Florida is located at 3735 11th Circle #103 in Vero Beach; call 772-563-2910 for further information.