From allergies to insomnia, there is a pill for just about every problem. The problem is, those pills often come with a lengthy list of potential side effects. And in the quest to cure what ails us as quickly as possible, those warnings are too often overlooked.

A new study, offers the most definite proof yet of what scientists have known for at least a decade: that anticholinergic drugs are linked with cognitive impairment and an increased risk of dementia.

Though you may have never heard of this class of drug, you have certainly heard of the medications themselves. They are sold over the counter and by prescription as sleep aids and for chronic diseases including hypertension, cardiovascular disease and chronic obstructive pulmonary disease (COPD).

Anticholinergic drug users showed lower levels of glucose metabolism - a biomarker for brain activity - both in the brain overall and in the hippocampus, a region of the brain associated with memory and which has been identified as affected early by Alzheimer's disease.

Of course, never start or stop taking a medication without first consulting your doctor.