FIGURE 13.6 The Finnish Adoptive Family Study of Schizophrenia In the Finnish Adoptive Family Study, psychiatrist Pekka Tienari and his colleagues (1994, 2006) tracked the mental health of two groups of adopted individuals: one group with biological mothers who had schizophrenia and a control group whose biological mothers did not have schizophrenia. This graph shows the strong influence of the adoptive family environment on the development of serious mental disorders.