Stimulants used to improve cognitive function can include the following: caffeine, nicotine, cocaine, Ritalin and Adderall. Not all of these stimulants work in the same manner. Caffeine for example, does not have any effect of the dopamine system unlike cocaine, and does not give the patient a pleasurable rush. Cocaine, Ritalin and Adderall (if it is crushed) does give the patient a rush. All these cognitive enhancers work by improving focus and energy and decreases the patients need of sleep, which means he/she can study for longer periods of time. These drugs also appear to enhance the retention of recently learned information and also improves working memory and cognitive control. However, the chronic effects of these drugs used as cognitive enhancers are not known, and that is where the risk in taking them becomes evident. It is also possible that the misuse of the prescription stimulants may make the patient dependent on their effect in order to function in their daily/academic life. Some of the most common adverse reactions of prescription stimulants are lack of appetite and difficulty sleeping as well as less common effects like, tachycardia, anxiety, tremor and headache. Some people may regard the use of cognitive stimulants as academic dishonesty and because of its unknown log-term effects it is not recommended to use these medications as a means of academic support.