What class of drugs includes certain medications used for anxiety relief and treatment of insomnia?

The correct answer identifies barbiturates as a class of drugs that includes certain medications used for anxiety relief and treatment of insomnia. Barbiturates are central nervous system depressants that enhance the effect of the neurotransmitter gamma-aminobutyric acid (GABA). This action leads to sedation and a calming effect, which can alleviate anxiety and help with sleep disorders.

Historically, barbiturates were widely prescribed for these purposes, although their use has declined due to the risk of dependence and overdose. Nevertheless, understanding their role as anxiolytics and sedatives is crucial in the study of psychology and pharmacology.

Other mentioned classes like opiates and stimulants serve different purposes; opiates are primarily used for pain relief, while stimulants increase alertness and energy. Therefore, barbiturates remain significant in discussions about drugs for anxiety and insomnia.