|| Checking for direct PDF access through Ovid
Although drugs with dependence liability share common pharmacologic effects, particularly involving dopaminergic neurotransmission in the mesolimbic "reward circuit," they produce very different symptoms and signs of intoxication and withdrawal. For example, opioid overdose produces the triad of coma, miosis, and respiratory depression; opioid withdrawal produces flulike symptoms that are seldom life threatening. By contrast, sedatives and ethanol not only cause fatal respiratory depression in overdose but also produce withdrawal symptoms and signs, including seizures and delirium tremens, which can be life threatening. Methamphetamine, cocaine, and other psychostimulants in overdose cause delirium, hypertensive crisis, seizures, metabolic acidosis, and malignant hyperthermia; withdrawal symptoms, however, consist of hunger, fatigue, and depression. Other recreational drugs, including marijuana, hallucinogens, inhalants, phencyclidine, anticholinergics, and tobacco, produce their own constellation of symptoms and signs.