The article by Kyaga et al ^{Reference Kyaga, Lichtenstein, Boman, Hultman, Långström and Landén1} is an important contribution to the understanding of the selective advantage and disadvantage of common behavioural phenotypes. The accompanying editorial by Jamison puts this work in context and points out that the overlap between creativity and mental disorder is partial. ^{Reference Jamison2} The proportion of persons in creative professions in Sweden is about 1.1% (based on the 1990 Swedish census, ages 15-64, and excluding scientific professions). The figure for the USA is similar: 1.4%. ³ Our report in the neurological literature proposes that polymorphisms in the alpha-1-antitrypsin (A1AT) gene are a common genetic factor for both creativity and mental disorder. ^{Reference Schmechel4} The proportion of people in creative professions observed in 1537 consecutive patients was 3.7%. A highly significant 38% of people in creative professions carried one or more polymorphisms of the A1AT gene compared with the 13% carrier rate observed in the other participants in this study, ^{Reference Schmechel4} and similar to reported rates in European populations. When the larger proportion (20-30%) of the population that pursue creative avocations (acting, dancing, music, photography, visual arts, writing) are considered, the same relationship of A1AT carriers and creativity and ‘intense mental energy’, including clinical anxiety or bipolar disorder, is observed. ^{Reference Schmechel4} An extension of these previous clinical series now totals 3176 consecutive patients and confirms the original findings ^{Reference Schmechel4} (details available from the author on request). This means that creativity and mental disorder can overlap and one instance for many such cases may be the genetic and environmentally modulated interactions of A1AT liver protein and serum acute phase reactant. It is important to emphasise that not all artists are A1AT carriers and not all artists have intense goal-directed energy or even mood disorder, underlining the point of Jamison's editorial. Nevertheless, it is likely that many people carrying A1AT polymorphisms trade the selective advantage of intense creative energy (blessing) for the disadvantage of susceptibility to lung and liver disease, and potentially significant recurrent mood disorder (curse). Pulmonary disease is associated with bipolar disorder (see Schmechel ^{Reference Schmechel4} ), and A1AT polymorphisms would provide a genetic basis.