Attention-deficit hyperactivity disorder (ADHD) is a neurobiological and neurodevelopmental disorder with an idiosyncratic genetic base. ADHD presents various characteristics, such as inattention, hyperactivity, and impulsivity. Over the period, ADHD leads to noticeable functional disability. A five- to ten-fold progressed risk of disorder development is observed in the populations with familial history of ADHD. The abnormal structure of the brain in ADHD results in altered neural mechanisms, such as cognition, attention, and memorial function. The mesolimbic, nigrostriatal, and mesocortical pathways in the brain get affected by the deterioration of the levels of dopamine. The hypothesis of dopamine in ADHD and its etiopathology suggests that detained attention and impaired arousal functions are due to reduced levels of dopamine. The quickest way to improve strategical treatment is by clarifying the etiological aspects of ADHD and identifying the underlying mechanisms of pathophysiology, which will assist in exploring the biomarkers for better diagnosis. The implementation of life course theory is a very important research principle announced by Grand Challenges in Global Health Initiative (GCMHI). Long-term research is needed to define the progression of ADHD. Interdisciplinary collaborations promise a great future for research innovations in ADHD.