The authors of this study sought characterization of risk factors for ADHD in infancy may enable early intervention to diminish the symptoms that ensue, and reported ight parameters during infancy were found to be significantly associated with later development of ADHD: at 0 to 1 month—advanced maternal age, lower maternal education, family history of ADHD, and social problems; at 3 and 18 months—decrease in head circumference percentile; at 9 and 18 months—delay in motor and language development, and difficult temperament.
Gurevitz, Mina, Geva, Ronny, Varon, Maya, and Leitner, Tael. (2014). Early Markers in Infants and Toddlers for Development of ADHD. Journal of Attention Disorders, 18, 14-22.