Drug dependence is a mental state caused by the interaction between drugs and the organism, including somatic dependence and mental dependence. 1. Physical dependence: it is due to the body’s long-term use of a drug, resulting in the body has adapted to the existence of the drug, if the drug is stopped, the body will appear withdrawal symptoms, such as nausea and vomiting, insomnia, anxiety, depression and other typical manifestations, at this time, you must be given the drug again in order to alleviate. Usually seen in the more addictive sedative-hypnotic drugs, painkillers, such as morphine. 2. Mental dependence: also known as psychological dependence, the patient may not have any physical reaction after the use of drugs, but the psychological will get a great sense of satisfaction, and thus addictive, but after stopping the drug does not usually have physical withdrawal symptoms. For easy to have dependence on the drug when taking to pay extra attention, in the doctor’s professional guidance for taking and stopping the drug, not to take or stop their own private, so as to avoid adverse reactions.