It was found that a range of Neurotransmitters underlie in the brain malfunctioning in patients with ADD/ADHD (Blum et al., 2008). The Neurotransmitter pathways, including Dopamine & Noradrenaline, Serotonin, and Glutamate & GABA will be discussed in the presentation. Genes related to each of these pathways will be briefly outlined. Hormones, including Insulin, Adrenaline and Progesterone may also underlie in the mechanism of the chemical balance and behaviour in patients with ADD/ADHD. The hypothalamic-pituitary adrenal axis in patients with ADD/ADHD will be discussed in relation to the prevalence towards stress. Each mechanism and theory will be accompanied with case studies. Psycho-Nutritional therapy including bio identical hormones targeting each mechanism is also suggested.