Question

What causes ADD & ADHD?

Answer 1

ADD =acute diarrhoeal disease
Most often by an infection from certain viruses(ROTA virus,NoroVirus) or less often by bacteria (Salmonella, Shigella, Staphylococcus, Campylobacter jejuni, Clostridium, Escherichia coli, Yersinia, Vibrio cholerae, and others) their toxins (e.g. SEB), parasites, or an adverse reaction to something in the diet or medication.

ADHD=Attention deficit hyperactivity disorder
http://en.wikipedia.org/wiki/Adhd#Cause
The specific causes of ADHD are not known There are, however, a number of factors that may contribute to, or exacerbate ADHD. They include genetics, diet and the social and physical environments.
Researchers believe that a large majority of ADHD cases arise from a combination of various genes, many of which affect dopamine transporters.
The pathophysiology of ADHD is unclear and there are a number of competing theories.
Research on children with ADHD has shown a general reduction of brain volume, but with a proportionally greater reduction in the volume of the left-sided prefrontal cortex. These findings suggest that the core ADHD features of inattention, hyperactivity, and impulsivity may reflect frontal lobe dysfunction, but other brain regions particularly the cerebellum have also been implicated.

Answer 2

the truth is, no one knows for sure.

Attention Deficit Disorder or Attention Deficit Hyperactivity Disorder have theories only. There may be a genetic imbalance of hormones. There may be an environmental influence. It may be familial. It may be influenced by your diet.

A lot of may's but no real answers. It's more important to be able to identify whether the symptoms are or are not ADD/ADHD and then be able to manage the condition appropriately.