Smokers with schizophrenia report that the practice helps to reduce their symptoms. This has been confirmed by various studies proving that smoking is directly related to a reduction in the negative symptoms of the psychological disorder which include the lack of motivation, anxiety, and social withdrawal. Experts in schizophrenia believe that this effect is caused by nicotine's ability to increase dopamine levels in areas of the brain involved in awareness and interacting with the person's surroundings.