Can adderall (dextroamphetamine and racemic amphetamine) cause my boyfriend experience terrible personality changes?

Possibly: Stimulant medicines such as Adderall (dextroamphetamine and racemic amphetamine) can sometimes have side effects relarted to increased moodiness, agitiation, or irritability. So, yes, it is possible that this medicine could cause your boyfriend to have increased problems. It would be important for him to contact his physician as soon as possible to discuss this issue.