In the context of opioid use disorder, which of the following signs and symptoms is most likely to be observed?

In the context of opioid use disorder, diarrhea can be a significant symptom of withdrawal. Individuals who are dependent on opioids often experience a range of withdrawal symptoms when they reduce their use or discontinue opioids, and gastrointestinal disturbances, including diarrhea, are common during this phase. This occurs because opioids inhibit gastrointestinal motility; thus, when the opioids are withdrawn, the opposite effect—hyperactivity of the gut—can lead to diarrhea.

In contrast, the other symptoms listed are less characteristic of opioid withdrawal. Hypotension may occur in various situations but is not a primary or direct indication of opioid withdrawal. Small pupils, or miosis, is commonly associated with opioid intoxication rather than withdrawal, as individuals in withdrawal often present with dilated pupils. Somnolence can also be present in cases of opioid intoxication or overdose, but during withdrawal, individuals are more likely to experience insomnia or restlessness.

Thus, diarrhea stands out as the symptom most likely to be observed during withdrawal from opioids, making it the correct response in the context of opioid use disorder.