Which drug categories are known to cause Horizontal Gaze Nystagmus (HGN)?

Horizontal Gaze Nystagmus (HGN) is a type of involuntary eye movement that can be used as a key indicator of certain drug influences during field sobriety testing. The correct choice identifies CNS depressants, inhalants, and dissociative anesthetics as drug categories that are known to cause HGN.

CNS depressants, such as alcohol and benzodiazepines, typically impair the function of the central nervous system, leading to effects that can include slowed reaction times and coordination issues, and can trigger HGN due to their impact on the brain's control over eye movements. Inhalants can also disrupt normal brain function, resulting in HGN as part of their intoxicating effects. Dissociative anesthetics, like PCP, interfere with motor control and perception, and can similarly lead to observable HGN.

These categories of drugs generally depress the CNS, affecting the vestibular system, which plays a key role in balance and eye movement regulation. As a result, individuals under the influence may exhibit HGN when their eyes are asked to track a moving object horizontally.

Each of the other drug categories, while they may produce various effects on the body and mind, do not typically cause the same distinctive eye movement response associated with H