 While stimulants and atomoxetine are usually safe , there are side @-@ effects and contraindications to their use . A large overdose on ADHD stimulants is commonly associated with symptoms such as stimulant psychosis and mania ; although very rare , at therapeutic doses these events appear to occur in approximately 0 @.@ 1 % of individuals within the first several weeks after starting amphetamine or methylphenidate therapy . Administration of an antipsychotic medication has been found to effectively resolve the symptoms of acute amphetamine psychosis . Regular monitoring has been recommended in those on long @-@ term treatment . Stimulant therapy should be stopped periodically to assess for continuing need for medication , decrease possible growth delay , and reduce tolerance . Long @-@ term misuse of stimulant medications at doses above the therapeutic range for ADHD treatment is associated with addiction and dependence . Untreated ADHD , however , is also associated with elevated risk of substance use disorders and conduct disorders . The use of stimulants appears to either reduce this risk or have no effect on it . The safety of these medications in pregnancy is unclear . 
