What is the classification of substances that includes central nervous system depressants and medications capable of causing physical dependence?

The classification that includes central nervous system depressants and medications capable of causing physical dependence is narcotics. Narcotics, also known as opioids, work by binding to specific receptors in the brain and spinal cord to relieve pain but can also depress the central nervous system. This category of drugs is well-known for its potential to lead to physical dependence and addiction, as consistent use can result in changes to brain chemistry and the body’s response to these substances.

Central nervous system depressants primarily slow down brain activity, leading to effects such as sedation, drowsiness, and potentially life-threatening respiratory depression, especially at higher doses. This makes proper management of narcotics essential in both clinical and therapeutic settings to minimize the risk of dependence and withdrawal symptoms when the medication is discontinued.

The other classifications provided do not encompass the characteristics described in the question. Analgesics are primarily focused on pain relief without necessarily being associated with dependence, stimulants increase brain activity and are not depressants whatsoever, and antihistamines are mainly used to treat allergic reactions and do not typically cause physical dependence in the way narcotics do.