Sleep Disturbances



Sleep Disturbances





Sleep disorders are extremely common: 40% of the population have had trouble sleeping within the past year, 10% have had diagnosable insomnia, and 3% to 4% have had hypersomnia (1,2,3).

Current understanding and classification of sleep problems rests on knowledge of normal sleep. Much of this has been obtained through polysomnography (4), that is, electrophysiologic measures (EEG, EMG, EOG), as well as airflow, O2 saturation, etc., of patients in sleep laboratories. The two major categories are the dyssomnias (poor sleep, excessive sleep) and the parasomnias (peculiar events associated with sleep).


NORMAL SLEEP

Normal sleep is cyclical (four to five cycles/night) and active, not passive. Distinct stages [rapid-eye-movement (REM) and non-REM sleep], measured by EEG, occur each night. From waking (beta waves; alpha waves, 8 to 12 cps), sleep is initiated by melatonin release from the pineal gland and passes stepwise through discrete stages during the night:


NREM Sleep

Low level of activity: reduced blood pressure (BP), heart rate, temperature, and respiratory rate. Good muscle tone and slow, drifting eye movements.


Stage 1: (5% of sleep), lightest sleep, a transition stage; lowvoltage, desynchronized waves.

Stage 2: (50%), mostly theta waves (low voltage, 5 to 7 cps) but with some bursts of sleep spindles (13 to 15 cps for 2 to 3 seconds) and high spikes (K complexes); awakens easily.

Stage 3: Theta with some delta waves (high voltage at 0.5 to 2.5 cps).

Stage 4: Deepest sleep (hard to awake), mostly in first half of night; mostly delta waves.



REM Sleep


Active sleep (20% to 25% of sleep), characterized by rapid synchronous eye movement, twitching of facial and extremity muscles, penile erections, and variation in pulse, BP, and respiratory rate. Muscles appear paralyzed (no tone). Depth is similar to stage 2; theta waves, sleep spindles, and K-complexes reappear. Dreaming can occur in several stages but is most common in REM sleep. Brain activity is quite elevated.

Patients enter lightest sleep (stage 1), descend by steps over approximately 30 minutes to deepest sleep (stage 4), plateau there for 30 to 40 minutes, and then ascend to lighter stages (1 to 2) to enter REM sleep 90 to 100 minutes after falling asleep. Then the cycle repeats. As the night progresses, the REM periods lengthen, stage 4 disappears, and the sleep is generally lighter. The length of time spent in any one stage varies in a characteristic fashion with age (e.g., longer stages 3 and 4 in youth, shorter and fewer in old age). The significance of each stage is not known. Serum cortisol is low initially during the night but peaks just before awakening.

For clinical purposes, patients can be divided into those complaining of insomnia or hypersomnia. In each category, distinct syndromes must be ruled in or out.


INSOMNIA


Primary Insomnia (DSM, p. 599, 307.42)

Primary insomnia is persistent insomnia that has been present for at least 1 month and has no obvious cause. Explore the differential diagnosis. Take a good history of the sleep problem; include the 24-hour sleep-wake cycle (sleep laboratory studies usually are not needed). Identify the pattern: trouble falling asleep (onset insomnia), trouble staying asleep (frequent awakenings), early morning awakenings (terminal insomnia). Inquire about life stresses, drug and alcohol use, and marital and family problems. Rule out the following:



  • Is the insomnia simply normal sleep?



    • Some “insomniacs” get ample sleep (sleep-state misperception syndrome or pseudoinsomnia); they just believe they sleep poorly. Use reassurance and psychotherapy.


    • Sleep time lessens with age—explain to concerned elderly. Help them avoid a “worry over sleeplessness” cycle.



    • Some patients are substance abusers seeking drugs; do not be fooled.


  • Is the insomnia transient (situational insomnia)? This is the most common form of insomnia: usually trouble falling asleep, due to worry. Identify the stress. Help the patient deal with it. Consider time-limited (1 to 2 weeks) use of sleeping medication (e.g., zolpidem, 5 to 10 mg p.o., hs; temazepam, 15 to 30 mg p.o., hs). Differentiate from psychophysiologic or conditioned insomnia: The patient has inadvertently trained him or herself to stay awake at bedtime, usually by worrying about not falling asleep (a type of primary insomnia).


  • Is a chronic minor psychiatric illness present? Prolonged insomnia (usually sleep-onset problems with decreased stage 4 sleep) is common with chronic depression or anxiety or both (and obsessive-compulsive patients). They may self-medicate, producing more insomnia. Such patients may have trouble expressing distressed or aggressive feelings and thus internalize their problems.


  • Is a major psychiatric illness present (INSOMNIA RELATED TO ANOTHER MENTAL DISORDER; DSM, p. 645, 307.42)?



    • Acute psychosis: Often produces major sleep disruption—use antipsychotics.


    • Mania or hypomania: Very short sleep time—use anticonvulsants or lithium.


    • Major depression: Typically early morning awakening, but frequent awakenings during the night are also common. REM sleep begins very quickly after sleep onset (short REM latency). Treat the depression with SSRIs, etc.


  • Is a medical problem present (SLEEP DISORDER DUE TO A GENERAL MEDICAL CONDITION, INSOMNIA TYPE, DSM, p. 651, 780.52)?



    • Nighttime pain or distress, often with related anxiety and depression [e.g., back pain, headache, arthritis, asthma, nocturnal angina (increased chest pains during REM sleep), duodenal ulcer].


    • Hyperthyroidism, epilepsy, parkinsonism, chronic renal failure.


    • Is the patient simply worried about a medical problem?


  • Is substance use or abuse present (SUBSTANCE-INDUCED SLEEP DISORDER, DSM, p. 655)? It is very common, so always inquire.

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Sep 12, 2016 | Posted by in PSYCHIATRY | Comments Off on Sleep Disturbances

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