The class of organic/inorganic small molecules dominate the PD field (Figure ). There is considerable variation in the distribution of substance classes between journal articles and patents. While small molecules strongly dominate in the patents (>70%), in the journal articles small molecules, nucleic acids, and proteins/peptides are nearly equally represented (28%, 39%, and 27%, respectively) (Figure , inset). That difference is not unexpected, since small molecule drugs are of certain commercial interest and thus more represented in patents, while journal articles generally discuss more fundamental features of the disease thus discussing all three classes of substances.