ADD/ADHD Attention-Deficit Hyperactivity Disorder (ADHD) is a common childhood disorder characterized by persistent and developmentally inappropriate levels of overactivity, inattention, and impulsivity; a condition that can persist into adulthood.

ADD/ADHD is the most common psychiatric disorder in youth with 9.5% of school-aged children affected in Australia and New Zealand and over 10% in the United States. The disorder not only interferes with the learning ability of a child, it also creates a great deal of stress in family life and interpersonal relationships.

Behaviour is affected in ADHD and is due to imbalances of specific neurotransmitters (i.e. noradrenaline)- impacting the executive functions of the prefrontal cortex of the brain – the area of the brain involved in planning complex cognitive behaviors, personal expression, decision making and moderating social behavior. Patients may have either too little or too much of these neurotransmitters, have defective receptor function and methylation defects – that ultimately compromises the fluidity of neuronal membranes and neuronal synchronization during attention-demanding tasks.

Currently, there are no biomedical tests for ADHD, so the condition is diagnosed by the observation of behavioral symptoms. The diagnostic criteria for ADHD are 9 symptoms in two areas of mental functioning: inattention and hyperactivity/impulsivity (see symptoms below). A child only needs 6 of these 9 symptoms in either area to obtain a diagnosis. There are around 500 different possible combinations of these 9 symptoms which means a child can present in many different ways and still reach a diagnosis of ADHD. Due to the variability of symptoms, ADHD has been classified into 3 subtypes:

1. Predominantly hyperactive-impulsive: the majority of symptoms are in the hyperactivity/impulsivity category
2. Predominantly inattentive: the majority of symptoms are in the inattentive category
3. Combined hyperactive-impulsive and inattentive: 6 or more symptoms of each type.

Several lines of evidence support a disturbance in the gut/ brain/immune (GBI) axis. The gut/brain axis is particularly affected as toxicity, and food constituents have been identified as drivers of brain dysfunction in ADHD. Family studies also reveal a strong genetic link in ADHD, where multiple genes have been identified which involve specific neurotransmitter receptors or transport. However, it is also recognized that environmental triggers, such as heavy metals are shown to induce oxidative stress, lower intracellular glutathione levels and inhibit methylation in neurons, contributing to the ADHD phenotype.