How "blind" are double-blind placebo-controlled trials of benzodiazepine hypnotics?

This study examined the accuracy of insomnia patients and their treating physicians in rating whether an active hypnotic drug or a placebo was given in treatment. Forty older adults with primary insomnia were randomly assigned to either an active (temazepam) or a placebo condition using a double-blind strategy. Ratings of treatment conditions were obtained at 1 week (early treatment), 4 weeks (midtreatment), and 8 weeks (late treatment). Patients were able to accurately discriminate (beyond chance levels) between the active and placebo medications at the early (76.9% accuracy) and late treatment assessment timepoints (78.1% accuracy), but not at midtreatment (51.5% accuracy). Therapists, however, were able to make accurate discriminations at the late treatment assessment timepoint only (80% accuracy); early (69.2% accuracy) and midtreatment (47.2% accuracy) ratings did not exceed chance levels. Patients who had used hypnotic drugs prior to this trial were more accurate in their judgments of treatment conditions than those without prior exposure. The findings raise an important issue about the internal validity of the double-blind strategy, which may in fact be only a single-blind procedure.

Dysfunctional beliefs and attitudes about sleep among older adults with and without insomnia complaints.

This study examined the beliefs and attitudes about sleep among 145 older adults. Ss were either chronic insomniacs (n = 74) or self-defined good sleepers (n = 71). They rated their level of agreement or disagreement (visual analog scale) with 28 statements tapping various beliefs, expectations, and attributions about several sleep-related themes. The results showed that insomniacs endorsed stronger beliefs about the negative consequences of insomnia, expressed more hopelessness about the fear of losing control of their sleep, and more helplessness about its unpredictability. These findings suggest that some beliefs and attitudes about sleep may be instrumental in perpetuating insomnia. The main clinical implication is that these cognitions should be identified and targeted for alteration in the management of late-life insomnia.

Neuropsychological functioning in older insomniacs with or without obstructive sleep apnea.

The relationships between neuropsychological functioning and sleep loss, sleep apnea, and hypoxemia were examined. Forty-five older insomniacs (M age = 64.6 years) with or without sleep apnea were administered neuropsychological tests after 1 night of nocturnal monitoring in a sleep laboratory. The results showed few differences on cognitive and psychomotor performance between individuals with sleep disruptions alone compared with those whose insomnia was associated with sleep apnea and hypoxemia. There were no significant relationships between nocturnal sleep and respiratory variables and daytime functioning. Furthermore, cognitive and psychomotor performance in older insomniacs with or without sleep apnea revealed minimal impairment compared with age-matched normative data. The results suggest that when the severity of sleep disruptions is controlled, there are minimal differences in neuropsychological functioning of older adults with mild to moderate sleep apnea compared with those without apnea.