 There are a number of non @-@ stimulant medications , such as atomoxetine , bupropion , guanfacine , and clonidine that may be used as alternatives , or added to stimulant therapy . There are no good studies comparing the various medications ; however , they appear more or less equal with respect to side effects . Stimulants appear to improve academic performance while atomoxetine does not . There is little evidence on their effects on social behaviors . Medications are not recommended for preschool children , as the long @-@ term effects in this age group are not known . The long @-@ term effects of stimulants generally are unclear with one study finding benefit , another finding no benefit and a third finding evidence of harm . Magnetic resonance imaging studies suggest that long @-@ term treatment with amphetamine or methylphenidate decreases abnormalities in brain structure and function found in subjects with ADHD . Atomoxetine , due to its lack of addiction liability , may be preferred in those who are at risk of recreational or compulsive stimulant use . Guidelines on when to use medications vary by country , with the United Kingdom 's National Institute for Health and Care Excellence recommending use only in severe cases , Switzerland strongly limits the authorised medications , while most United States guidelines recommend medications in most age groups . 
