Supporting this notion, the one prior study examining G × E interactions involving 5HTTLPR and ADHD found an association main effect with the more efficient "long" allele of 5HTTLPR (high serotonin transporter activity), yet an interaction with psychosocial adversity with the low-efficiency "short" allele of 5HTTLPR [42]. The gene discussed is SLC6A4; the disease is attention deficit-hyperactivity disorder.