This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Substance Abuse, Subject name: Psychiatry
[{'content': 'Symptom of opioid withdrawal is: \nSelect and explain. \nA. Piloerection, B. Dry Skin, C. Bradycardia, D. Pupillary construction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. PiloerectionOpioid Withdrawal* With long-term use of opioids down regulation of dynorphins, endogenous endorphins and opioid receptors takes place.* Abrupt cessation of opioid use does not allow time for upregulation of receptors It results in elevated neuronal firing and the opioid withdrawal syndrome.* Opioid withdrawal usually starts with-- Diaphoresis- Yawning- Feelings of anxiety- Lacrimation- Rhinorrhea and diffuses myalgias.It then progresses to -- Nausea- Profuse vomiting- Diarrhea, Piloerection, mydriasis and abdominal dehydration.* Opioid withdrawal reactions are not life-threatening and rarely fatal but they are very uncomfortable.* Vomiting and aspiration of gastric contents causes pneumonitis.', 'role': 'assistant'}]