A vast study seeks to understand the genetic underpinnings of ADHD

TRUE DISORDERADHDADHDDNA or mythical modern ailment? Attention-deficit hyperactivity disorder () is one of the most controversial topics in psychiatry. Not for the first time, the internet is brimming with conflicting information. Some deplore a lack of recognition and insufficient diagnoses and treatment. Others denounce overdiagnosis and overtreatment, and argue that the condition is bandied about willy-nilly as an excuse for poor parenting.Identifying the inherited underpinnings of has proved challenging. Studies of twins with and without its eponymous symptoms suggest that genetic factors bear between 70% and 80% of the blame for causing it. There is not, though—as there is in the case of (say) colour blindness—a clear gene or genes on which that blame can be pinned. Instead, the presumption is that a range of small and hard-to-detect tweaks in the sequence of letters (known as nucleotides) combine to bring about susceptibility to the disorder. Environmental factors such as social deprivation and low birthweight play a greater or lesser role (or sometimes none at all) depending on exactly which genetic tweaks are present.