Which of the following symptoms is indicative of sedative, hypnotic, or anxiolytic withdrawal?

The symptom indicative of sedative, hypnotic, or anxiolytic withdrawal is autonomic hyperactivity. During withdrawal from these substances, individuals can experience heightened autonomic responses, which may include symptoms such as increased heart rate, sweating, and elevated blood pressure. These reactions arise as the body attempts to readjust to functioning without the depressant effects of the substances.

Autonomic hyperactivity is a key factor because it reflects the body's transition from a state that was under the influence of sedatives, which typically depress central nervous system activity, to one where the central nervous system is in a state of heightened activity due to the absence of the substance. This adjustment can lead to a range of physiological symptoms that are quite distinct from the effects of the drugs themselves.

In contrast, excessive sleepiness is associated with the use of sedatives rather than withdrawal, while increased appetite and weight gain are not typical symptoms of sedative withdrawal, as individuals usually experience a loss of appetite during this phase. Understanding the specific symptoms of withdrawal is crucial for effective diagnosis and intervention in substance use disorders.