- The dopamine D4 receptor and the hyperactivity phenotype: a developmental-epidemiological study. Mill, J.S., Caspi, A., McClay, J., Sugden, K., Purcell, S., Asherson, P., Craig, I., McGuffin, P., Braithwaite, A., Poulton, R., Moffitt, T.E. Mol. Psychiatry (2002)