Attention-deficit/hyperactivity disorder is one of the most common behavioral disorders among American children, accounting for 5% of school-age children and 2 to 4% of adults diagnosed. ADHD is diagnosed by consistent debilitating behaviors of hyperactivity and inattention, but it is often misdiagnosed in children who are younger than their classmates, for this reason Xiaolong Peng, Pan Lin, Tongsheng Zhang and Jue Wang (2013) worked with a large MRI dataset of children diagnosed with ADHD to create an effective biological diagnostic tool. A diagnostic tool based on five different brain factors prevalent in ADHD patients would also help improve the understanding, prevention and treatment of ADHD. Because ADHD patients' behavior interferes with every aspect of daily life, from personal relationships to education, this is the reason, according to Kathryn L. Humphreys, Shaina J. Katz, Steve S. Lee and Constance Hammen (2013), for whom ADHD generally precedes the onset of depression. Humphreys looked at different aspects of the lives of children with ADHD, such as problems with peers and parent-child difficulties, to determine which was the best predictor of later onset of depression. This research is very relevant in today's society where 10% of the population is affected by depression during their lifetime. The causes of depression are so varied that all predictors need to be studied thoroughly. ADHD is a very common predictor of long-term depressive behavior in adults. There is substantial evidence that links these two behaviors across different stressors during the childhood of children with ADHD. However, there is less research to show the biological links between the two disorders. There...... middle of paper ...... advances and allows us to see in more detail the structures of the brain and their minute differences like a smaller amygald which has a drastic effect on behavioral regulation and control impulses. There is still much to understand about these disorders and how to better cope with them. Works Cited Pinel, J. (2011). Cognitive and emotional disorders. Biopsychology (8th ed.,). Boston: Allyn & Bacon. Najman, JM (). The association of ADHD and depression: Mediation by peer problems and parent-child difficulties in two complementary samples. Journal of Abnormal Psychology, 122, 854-867. Hu, D. (). Extreme machine learning-based classification of ADHD using brain structural MRI data. PLoS ONE, 8, e79476.Stauber, F. (). Amygdala reduction in ADHD patients compared to major depression and healthy volunteers. Acta Psychiatrist Scand, , 111-118.