People who suffer from insomnia and other sleeping disorders also report higher rates of anxiety. A team of researchers from the Boston University School of Medicine conducted a study on rats in which they administered different doses of eszopiclone (Lunesta) and zolpidem (Ambien) — the most commonly prescribed drugs for treating insomnia — to monitor their effects on sleep and anxiety.
The researchers performed their experiment on 56 adult male rats. Head surgery was performed on the animals to implant electrodes designed to monitor the rodents’ brain waves and muscle movement. The animals were given 1, 3 and 10 mg doses of eszopiclone and zolpidem. To induce anxiety in the rats, some of them received electrical shocks to their feet. To test the memory of the rodents, they were put back in the shock chamber without any shock to monitor their contextual memory. If a rat shows so-called “freezing behavior” (essentially standing still), they are considered to have higher levels of memory of the shock chamber.
To measure the anxiety level of the rats, they were placed in a device called an elevated plus-maze. The maze stands about 20 inches above the ground and is shaped like a cross. One bar of the cross has walls and a ceiling and the other cross bar had no sides and roof. The rats were placed in the center of the cross facing an enclosed arm and recorded to see how freely they walked around. Since rats don’t like open spaces, rats with higher levels of anxiety will enter the open arm less frequently and spend less time there.
The rats were divided into eight different groups, with some receiving shock and drug treatments, while others were neither shocked nor drugged.
The researchers found the foot-shocked rats remained awake a lot longer than their non-shocked counterparts and also had less REM sleep. Shocked rats who had a 1 mg dose of eszopiclone and 3 mg dose of zolpidem had better sleep than the shocked rats who were not given any injections.
The rats receiving the foot shocks, not surprisingly, avoided the open arm of the elevated plus-maze more than the non-shocked rats. Shocked rats that received low doses of eszopiclone behaved like the control group that received no shocks, meaning that the low doses blocked the anxiety from the foot shocks. At the high dose rate of both drugs, the shocked rats had difficulty keeping their balance while walking.
As for memory, the lowest dosage of eszopiclone lead to freezing behavior that was similar to the behavior of shocked rats that were not drugged, suggesting that the low dosage doesn’t affect memory.
It should be noted that the study was supported by Sepracor Inc., the maker of eszopiclone, and the National Institutes of Health. If you’re suffering from insomnia or another sleep disturbance disorder and have anxiety issues, talk to your doctor about medications that could help alleviate both.