It is used for smoking cessation to relieve withdrawal symptoms. Discontinuation may result in the appearance of withdrawal symptoms. Bupropion reduces the severity of nicotine cravings and withdrawal symptoms. An integral effect is the alleviation of symptoms of opioid withdrawal. It can also result from alcohol withdrawal or benzodiazepine withdrawal. Kindling also results in the intensification of psychological symptoms of alcohol withdrawal. These can include a range of symptoms similar to those of benzodiazepine withdrawal. MSNs is a potential mechanism of aversion produced by drug withdrawal. Positive symptoms are a common cause of apathy, social withdrawal, and alogia. There is insufficient evidence to support the use of baclofen for alcohol withdrawal syndrome. Phenobarbital is used in cases of drug withdrawal syndromes. Some intense stimuli trigger reflex withdrawal, certain autonomic responses, and pain. Calwell called for an "immediate and unconditional withdrawal" of Australian troops from Vietnam. Piloerection is one of the signs of opioid withdrawal. Gruelling scenes of resuscitation and drug withdrawal follow.