Once again a study on the use of hypnotics (aka "sleeping pills") has made its way into the headlines. This time it was an (online) publication of the British Medical Journal. Again, this study was a retrospective study, which compared patient who took sleeping pills with those who did not, and looked for clinical differences.
As readers of my blog are well aware, I firmly believe that the results of such studies should be used to generate a hypothesis, and not to come to a clinical conclusiuon, This hypothesis must then be tested in a forward study, i.e. now compare users of sleeping pills with non-users for the next two years. One of the most cited retrospective studies was a diet study of American females, which showed that those on a "low-fat" diet had a lower incidence of breast and colon cancer. A five-year study was then done, comparing the cancer rates of American females on a low-fat diet (defined as having fats make up less than 15% of their total daily calories) with those on their regular diet. NO DIFFERENCE was found in the breast or colon cancer rates of these two groups. Nevertheless, the American Cancer Society still recommends a low-fat diet as a cancer preventative.
There can always be confounding effects that invalidate a retrospective study. The first study of coffee drinkers showed that they had significantly more heart attacks than non-coffee drinkers. This created great alarm and various degrees of belief and disbelief, until one epidemiologist realized that more coffee drinkers smoke cigarettes than do non-coffee drinkers, and this was the overwhelming confounding factor and largest risk factor for heart attacks
Insofar as sleeping pills and lack of sleep is concerned (I had written a blog on this in 2009) I am more concerned with the mental effects of lack of sleep than I am with the effects of sleeping pills. The federal government limits the number of hours per day and per week that an interstate trucker can drive as well as the number of hours a commercial pilot can fly. Healthy young medical interns are limited as to the amount of consecutive hours they can work whereas much older physicians such as myself have no such limitation.Lack of sleep impairs concentration, increases irritability, increases the errors made on the job, degrades ego functions, makes one more susceptible to depression, and decreases stamina. I would like to see a study comparing the cognitive functions of patients taking sleeping pills with a matched control group of sleep-deprived patients, to determine which group had the greater dimunition of CNS executive functions. Another study would be to compare for two years the health of an age-matched group wherein both asked for sleeping pills, and only half of them were given the prescription. Then we would have a direct comparison of underslept patients with those on sedative-hypnotics.