Nutritional deficiencies: The conventional focus is that there is an imbalance of neurotransmitters in the brain but if we look a bit deeper and ask how neurotransmitters are made, we then realise that nutrients are the building blocks. Often symptoms will improve when you address nutrient imbalances or deficiencies, or the reason for these in the first place. Which can be linked to poor diet, or poor absorption.
Genetics: If you have certain gene polymorphisms there may be an increased need for certain nutrients as is the case in pyroluria or methylation issues. These can affect how neurotransmitters are made, metabolised and cleared.
Microbiome: The microbiome in our digestive tract has a huge role to play in brain health through its effect on the upregulation of proinflammatory cytokines (immune molecules that increase the inflammatory response), altered mitochondrial function, blood-brain barrier or gut permeability changes, and stimulation of the nervous system via the vagus nerve. The gut microbiome also influences available nutrients essential for the developing nervous system e.g. parasites can steal important nutrients like zinc and iron, which are crucial to the creation of our neurotransmitters, or an overgrowth of certain bacteria which create metabolites that affect the brain, such as D-lactate. Lack of specific beneficial bacteria such as Lactobacillus species can also lead to high levels of neuroinflammation and lowered immunity.
Oxidative Stress: Oxidative stress is a state produced by an imbalance between antioxidants and oxidants in the cells. This imbalance leads to higher levels of reactive oxygen species (ROS), which increases oxidation of neurons, leading to neuroinflammation.
Heavy metals: Exposure to heavy metals such as lead, mercury, aluminum, arsenic and cadmium are well known to increase susceptibility to ADHD, as they are neurotoxic and can replace important nutrients such as zinc, iron and selenium in creation of neurotransmitters. Lead especially is associated with mental retardation and hyperactivity. These exposures can take place in utero or can be from an environmental exposure.
Chemical exposure: Exposure to environmental chemicals, including naphthylamine, nicotine (found in cigarette smoke), bisphenol A, organophosphate pesticides (an OC class), has been linked to the diagnosis of ADHD and related symptoms.
Elevated copper: Copper is a necessary metal involved in the dopamine pathway however when in excess it can interfere with zinc metabolism, and enhances the biogenic amines. (neurotransmitters that stimulate brain activity). The effects of excess copper include hyperactivity, mood swings, anxiety, panic attacks, depression and anti-social behavior.
Yeast Overgrowth: Chronic yeast overgrowth can cause many symptoms in susceptible people, including behavioral changes. A combination of factors lead to the overgrowth of the common yeast, candida albicans, including diets high in sugar and carbohydrates, repeated use of antibiotics that kill the normal intestinal flora, steroid and hormone therapy (like the oral contraceptive pill) and copper imbalance.