Figure 1. Disease concepts of major psychoses.

Figure 2. Family and twin studies in major psychoses. Data of pooled samples from Gottesman (1991) and Craddock and Jones (1999). Estimates of risk in second-degree relatives of bipolar probands are not given because of lack of reliable data. Concordance rates for bipolar disorder are derived from the largest study. (From Bertelsen et al. (1977).)

Figure 3. Multifactorial threshold (MFT) model. The MFT model consists of several genes and environmental factors and assumes that the total liability is normally distributed in the population, such that those whose liability exceeds a certain threshold develop schizophrenia. (Courtesy of Irving I. Gottesman.)

Figure 4. Genomic overview of evidence for linkage in schizophrenia. Pooled data from 60 peer-reviewed linkage studies. Each dot represents evidence for linkage obtained in an independent sample. The level of significance is shown according to the criteria of Lander and Kruglyak (1995). Black indicates significant (lod score ³3.6), gray suggestive (lod score ³2.2) evidence and white hints (P£ 0.05) for linkage. (Adapted with permission from Moises et al. (2002), published by BioMed Central [http://www.biomedcentral.com/1471-244X/2/8/].)