The sheer number of Galvin children who went on to develop schizophrenia or related disorders raises an obvious question about the nature of the disease; it seems almost impossible that six of the 12 could be affected simply by chance, so there must be a common thread running through the different cases. However, what that thread is isn’t immediately clear. While the children all share the same genetic heritage, they also share more or less the same upbringing. In this way, the Galvin family’s situation influences a broader, longstanding debate about the respective roles of nature and nurture in the development of mental illness.

As Kolker details, this debate has been raging in one form or another since the 19th century and was a contributing factor to the rift that developed between Sigmund Freud and his protégé Carl Jung. At the time the Galvin boys were beginning to experience symptoms, the pendulum had swung towards the Freudian view that schizophrenia was environmental in origin and, more specifically, the result of bad parenting. According to a theory first proposed by psychoanalyst Frieda Fromm-Reichmann, so-called “schizophrenogenic mothers” caused their children to withdraw into psychosis to escape these women’s alternately domineering and withholding demeanor: “The child feels helpless, frightened, frustrated, anxious—ensnared, with no way out.