Sleep Apnea and Psychiatric Illness 1/17/2019

There is an interesting relationship between obstructive sleep apnea (OSA) and psychiatric disorders, particularly major depressive disorder (MDD). Given that both are commonly seen in the primary care setting, it is important for providers to understand that relationship in more detail. OSA can play a role in exacerbating medical problems in people with mental health illness.

The prevalence of OSA is growing as obesity in the United States increases. Risk factors for OSA include obesity, a craniofacial abnormality, an upper-airway abnormality, genetic predisposition, smoking, and nasal congestion. Common symptoms of OSA include choking and gasping, reflux, restless sleep, snoring, cognitive dysfunction, morning headaches, poor concentration, irritable mood, and daytime sleepiness. Problems with executive function can occur with OSA because of prefrontal dysfunction caused by intermittent hypoxia. Mood symptoms that can be related to decreased sleep that occurs with OSA include: poor concentration, lack of motivation, poor mood regulation, and irritability, as may not represent a separate mental health diagnosis if other symptoms are not present.

Some of these symptoms overlap with the symptoms of depression, such as poor concentration, daytime fatigue and irritable mood. Studies are showing a co-occurrence of MDD and OSA with a higher prevalence of one if the other is present. Studies show anywhere from a 2-3 fold increase, depending on the severity of the OSA, in MDD in patients with OSA. The mechanism of the relationship between OSA and MDD is not well-established. Hypotheses include: involvement of common neurotransmitters, like serotonin; common risk factors, including age, obesity, metabolic and cardiovascular problems; or a more direct causal link between the two.

Sleep symptoms reported during the course of major depression might be related to underlying OSA. These symptoms can include snoring, feeling fatigued despite adequate number of hours in bed, and middle of the night awakening for no apparent reason. There is a theory that frequent awakening due to choking from breathing cessation might play a role in the development of anxiety in patients with OSA.

OSA is highly co-morbid with patients with schizophrenia. In one study, OSA was diagnosed in patients with schizophrenia 6 times more often than in patients with other psychiatric diagnoses. Risk factors include obesity, male gender and chronic antipsychotic administration. OSA can sometimes be underdiagnosed because patients with schizophrenia are less likely to seek general medical care and the daytime sleepiness might be assumed to be related to a medication side effect rather than a symptom of OSA.

If OSA is suspected, a polysomnogram should be considered and treatment can then be initiated. There are cases where patients’ MDD symptoms improve with adequate treatment of their OSA without an adjustment in their depression treatment. Given this, one interesting consideration is that undiagnosed and untreated OSA could contribute to treatment-resistant MDD or antidepressant medication failure.

The combination of OSA and mental health illness can have a dramatically negative effect on a person’s quality of life. OSA and psychiatric illness, especially depression, often co-occur. It is important to screen patients with risk factors for a sleep disorder. For optimal results, it is important to treat comorbid psychiatric illness and OSA concurrently.

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