Why the drugs affect your mind
Both anticholinergics and benzodiazepines affect the activity of neurotransmitters—chemical messengers that work in the central nervous system—but the drugs work in slightly different ways.
Anticholinergic drugs block the action of acetylcholine.
In the brain, acetylcholine is involved in learning and memory. In the rest of the body, it stimulates the autonomic nerves—those that regulate contractions of blood vessels, airways, and our cardiovascular and digestive systems. The strongest anticholinergic drugs include some antihistamines, tricyclic antidepressants, medications to control overactive bladder, and sleeping pills.
Benzodiazepines boost another neurotransmitter’s effectiveness.
They make gamma-aminobutyric acid (GABA)—which slows the activity of neurons in the brain-—more potent. For that reason, they are used to calm anxiety and help people sleep.