Several research groups in the 1970s and early 1980s used polysomnography to study the sleep of male alcoholics undergoing inpatient alcoholism treatment, both following alcohol administration and during alcohol withdrawal (Allen et al. 1980
; Gross et al. 1973
; Gross and Hastey 1975
; Wagman and Allen 1975
; Zarcone 1978
In most of these studies, alcohol administration to alcoholic patients resulted in difficulty falling asleep (i.e., prolonged sleep latency), decreased total sleep time, increased SWS%, decreased REM%, and increased REM sleep latency (see ). Only one study (Allen et al. 1980
) found an increased total sleep time after alcohol administration to alcoholic patients.3
In addition, Gross and Hastey (1975)
noted that the baseline SWS% of alcoholic patients ranged widely from 0.7 to 44 percent and that alcohol-induced increases in SWS% depended on the baseline values of SWS%. Thus, when baseline levels of SWS% were less than 20 percent, heavy drinking produced either no change or a decrease in SWS%. Conversely, when baseline levels of SWS% were between 20 and 40 percent, heavy drinking resulted in an increase in SWS%.
Figure 1 A summary of nocturnal sleep changes in alcoholic patients as determined across various polysomnographic studies of acute alcohol administration and withdrawal. The studies measured sleep characteristics at baseline, after drinking, and during acute alcohol (more ...)
When the sleep of alcoholics was studied during withdrawal, sleep latency remained increased and total sleep time remained decreased compared with baseline levels (see ). In contrast, SWS% and REM sleep latency decreased during withdrawal relative to drinking nights and returned to baseline levels. Finally, REM% increased during withdrawal and even exceeded baseline levels, a phenomenon called REM rebound. One small study of three alcoholic men who received alcohol (7.6 ounces of pure alcohol) for 4 to 7 days assessed sleep characteristics over several days of withdrawal (Allen et al. 1971
). In that study, REM% decreased during the first 2 to 3 days of withdrawal and then rebounded by days 5 and 6. However, this pattern of the effects of withdrawal on REM% has not been reported since.
Research results suggest that although some variability exists across studies, the following general conclusions can be drawn regarding sleep measures in alcoholics:
- Measures of sleep continuity (i.e., sleep latency and total sleep time) are disrupted on both drinking and withdrawal nights in alcoholic patients. The finding of increased sleep latency contrasts with decreases in sleep latency found in healthy (i.e., nonalcoholic) men after drinking alcohol and suggests that alcoholic patients develop tolerance to the sleep-inducing effects of alcohol but remain sensitive to its stimulating effects.
- SWS% increases during drinking and returns to baseline levels during withdrawal.
- REM sleep generally is suppressed during drinking and either rebounds (with respect to REM%) or returns to baseline levels (with respect to REM latency) during withdrawal.
Two other studies assessed sleep during acute withdrawal without using polysomnography. Mello and Mendelson (1970)
made behavioral observations of sleep among 40 male inpatients during a 5-day baseline period and a subsequent drinking period averaging 14 days during which most subjects drank from 12.5 to 16.0 ounces of pure alcohol each day. This drinking period was followed by a 3- to 6-day withdrawal period. The authors defined insomnia as sleeping less than the minimum number of sleep hours observed during baseline. Using this criterion, 25 percent of the patients (i.e., 10 patients) developed insomnia during the first 48 hours of withdrawal, and a total 58 percent of the patients (i.e., 23 patients) had at least 1 night of insomnia during the first 6 days of withdrawal. Closer inspection of the data indicated that in 5 of those 23 patients, the insomnia was possibly related to discontinuing medications for detoxification. Thus, in 18 of the 40 patients (i.e., 45 percent), the insomnia was associated with alcohol withdrawal. The authors concluded that insomnia was not an invariable finding during withdrawal from alcohol (see ). In addition, Caetano and colleagues (1998)
investigated the prevalence of insomnia as an acute withdrawal symptom among 748 men admitted to detoxification and residential treatment centers. The analysis, which used a structured interview to assess insomnia, found that 67 percent of the men reported insomnia. The findings of these two studies complement polysomnographic studies of acute alcohol withdrawal that found evidence of insomnia as indicated by increases in sleep latency and decreases in total sleep time.
The most severe manifestation of alcohol withdrawal is delirium tremens (DTs), which is characterized by tremors, agitation, and hallucinations. Several studies found that DTs are associated with fragmented sleep—that is, frequent awakenings or arousals that alternate with episodes of light sleep (i.e., stage 1) or REM sleep (Johnson et al. 1970
; Greenberg and Pearlman 1967
; Gross et al. 1966
). Immediately after an episode of DTs, light sleep predominates and REM sleep decreases, as indicated by significantly decreased SWS% and REM% and increased percentages of stages 1 and 2 sleep, compared with control subjects (Kotorii et al. 1982
). The frequent juxtaposition of waking, light sleep, and REM sleep during DTs, as well as the decrease in REM sleep that follows an episode of DTs, supports early theories that the hallucinations of DTs represent an intrusion of REM sleep processes into the waking state (for a review, see Zarcone 1978