An exploratory study of links between ADHD and a chromosomal mutation in a single family

The aim of this paper is to review evidence of genetic factors in the aetiology of Attention Deficit Hyperactivity Disorder (ADHD). The review examines our current understanding of ADHD, including behavioural criteria, development, and cognition. It is concluded that there are a number of limitations in our current understanding of ADHD, stemming from high levels of co-morbidity, qualitative differences among subtypes, variable research methodology and a heavy reliance on a top down approach to research. The research literature contains a large amount of variation in measurement associated with defining ADHD as a behavioural phenotype, hampering genetic research. It is concluded that there is strong evidence supporting a genetic component to ADHD. Family, twin and molecular studies suggest ADHD may be part of some continuum, with a number of disorders having common genetic vulnerability, and that many genes interacting with environmental variables may be involved. It is suggested that future research should be longitudinal and family based in order to link behavioural, cognitive and genetic characteristics of ADHD as they emerge across the lifespan, and thereby inform our understanding of ADHD on a number of levels.