IL-1β, which can induce the conversion of rat mesencephalic progenitor cells into a dopaminergic phenotype (Kabiersch et al., 1998; Ling et al., 1998; Potter et al., 1999), and IL-6, which is highly effective in decreasing the survival of fetal brain serotonergic neurons (Jarskog et al., 1997), seem to have an important influence on the development of the neurotransmitter systems involved in schizophrenia, although the specificity of these cytokines is a matter of discussion. Here, IL6 is linked to schizophrenia.