Saturday, October 07, 2006

Bipolar Disorder and Sleep

Sleep disturbance is a well-recognized feature of acute psychiatric illness, and is included in the diagnostic criteria of many of the affective and anxiety disorders. Recent research has found that disrupted sleep and sleep complaints are common in patients with affective disorder even between mood episodes. Treatment of disrupted sleep and the maintenance of a regular sleep/wake cycle are important components of the prophylaxis of mood episodes in bipolar disorder.
Sleep disturbance is a cardinal feature of bipolar disorder. During acute mania, patients exhibit markedly reduced sleep time and report a reduced need for sleep. Even when euthymic, sleep disturbance is common. In a recent study, 55% of euthymic bipolar patients had chronic insomnia (Harvey et al 2005). Children with bipolar disorder (who often display ultradian rapid cycling rather than distinct mood episodes) exhibit reduced sleep efficiency and frequent nocturnal awakenings (Mehl et al 2006).

Clinical vignette
JW, a single 25 year-old female with bipolar type I disorder, had been relatively stable for the last three years on a regime of lithium 600 mg twice daily and Ambien (zolpidem) 10 mg at bedtime. She had not had a distinct mood episode since her last episode of bipolar mania three years ago. She obtained 7 to 8 hours of sleep at night, and was satisfied with her job as a respiratory therapist working for a durable medical equipment (DME) company.
Four weeks ago, the DME company went out of business, and JW took a job as a sleep technician working for a growing sleep disorders center. This exciting job involved working 8 pm to 6 am Tuesday through Friday. JW was only able to sleep 5-6 hours after her shift, even with the aid of Ambien. She slept about seven hours on nights she was not working.
Three days ago, on a Saturday morning, JW felt unusually energized as she was finishing her shift. She drove home and spent the next sixteen hours cleaning her house from top to bottom. JW then slept for an hour and went to a dance club. She left the dance club when it closed at 3 am and returned to her house, where she slept for two hours. She exercised extensively on Sunday and showed up at the sleep center Sunday night. She told her co-workers she was there because she was now the owner of the sleep center and she wanted to make sure they were doing their jobs right. She was talking rapidly and pacing. JW became agitated when the the other sleep technicians refused to take orders from her. The medical director was called. He, with great difficulty, was able to convince her to go to the ER. The medical director and a technician drove her to the ER, where treatment was begun for a bipolar manic episode.

Comment: JW developed a manic episode with symptoms of grandiosity, decreased need for sleep, rapid speech, and increased goal-directed activity. A change in sleep habits can precipitate a bipolar mood episode. Night work and shift work have a destabilizing influence on bipolar disorder.

Bipolar disorder is treated with mood stabilizing agents such as sodium valproate, carbamazepine, or lithium. Addition of an antidepressant may be necessary to control bipolar depression. The maintenance a stable sleep/wake cycle, as well as regularization of the circadian rhythm, are key components of a relatively new psychotherapy for bipolar disorder, Interpersonal and Social Rhythm Therapy (IP-SRT). IP-SRT is most effective for mood episode prophylaxis in the maintenance phase of bipolar, and in individuals without significant medical comorbidity or anxiety (Frank et al 2005).
The above is from a chapter I am writing for Medlink Neurol0gy entitled "Sleep disorders associated with mental disorders". It is copyrighted by Medlink Neurology.

Tuesday, October 03, 2006

Viagra worsens sleep apnea

The National Sleep Foundation reports:
Each year, millions of men in American seek treatment for erectile dysfunction (ED), a condition that is often associated with obstructive sleep apnea (OSA). Since its introduction in 1998, Viagra has become the most common form of treatment for ED. It works by enhancing the effects of nitric oxide, a compound that relaxes muscles in the penis and allows for increased blood flow, triggering an erection. Now a new study by a team of Brazilian and American researchers suggests that a single 50-mg dose of Viagra may actually worsen symptoms of obstructive sleep apnea (OSA). The study involved 14 middle-aged men with severe OSA in a double-blind crossover study. Using polysomnography, the researchers analyzed the severity of symptoms and found a significant increase following a dose of Viagra compared to placebo.
Here is the abstract for the study:
A Double-blind, Placebo-Controlled, Crossover Study of Sildenafil in Obstructive Sleep Apnea
Suely Roizenblatt, MD, PhD; Christian Guilleminault, MD, BiolD; Dalva Poyares, MD, PhD; Fátima Cintra, MD, PhD; Adriana Kauati, PhD; Sergio Tufik, MD, PhD
Arch Intern Med. 2006;166:1763-1767.
Background Sildenafil prolongs the action of cyclic guanosine monophosphate and nitric oxide by inhibiting cyclic guanosine monophosphate–specific phosphodiesterase 5. It is largely used for erectile dysfunction, a highly prevalent condition in obstructive sleep apnea. Because nitric oxide promotes upper airway congestion, muscle relaxation, and pulmonary vasodilation, the aim of this study was to establish the impact of a single 50-mg dose of sildenafil on the sleep of patients with severe obstructive sleep apnea.
Methods Fourteen middle-aged men with severe obstructive sleep apnea were consecutively selected for this double-blind, placebo-controlled, crossover study. Exclusion criteria were obesity, cardiovascular and/or respiratory disease, and conditions that interfere with sleep. All-night polysomnography was preceded by a single 50-mg dose of sildenafil or matching placebo randomly administered at bedtime, after a washout period of 1 week.
Results In comparison to placebo, a single 50-mg dose of sildenafil significantly increased the percentage of total sleep time with an arterial oxygen saturation of less than 90% (mean ± SD, 14.2% ± 9.1% vs 8.5% ± 3.2%, P<.01), without a difference in the nadir of oxygen desaturation. The mean arterial oxygen saturation also decreased (92.1% ± 1.91% vs 93.8% ± 1.3%, P = .02), and the desaturation index increased (30.3 ± 18.1 events per hour vs 18.5 ± 14.6 events per hour, P<.001). There was an increase in apnea-hypopnea index (42.4 ± 25.5 events per hour vs 34.6 ± 24.1 events per hour, P = .01), involving mostly obstructive events.
Conclusion In patients with severe obstructive sleep apnea, a single 50-mg dose of sildenafil at bedtime worsens respiratory and desaturation events.

Based on this study, physicians should be cautious in prescribing Viagra, Cialis, or Levitra in patients with known or suspected untreated severe obstructive sleep apnea.