Several lines of evidence suggest a role for the immune system in the multifactorial pathogenesis of schizophrenia and other psychiatric and neurodegenerative disease. Later, the role of immune mediators like cytokines became a source of main interest related to the process on inflammation in the CSM. In this article we report the results of our research on cytokines in a different groups of psychiatric patients following their clinical symptomatology and the course of diseases. In particular, we observed a prevalent type 1 cytokine profile in acute multiple sclerosis patients, while IL-10 production predominated in stable multiple sclerosis individuals. The modifications of cytokine profiles observed in schizophrenic patients suggests that clinical improvement is associated with a reduction in the inflammatory-like situation present in those not currently under treatment. Our data on Alzheimer's disease (AD) support the role of the inflammatory process in the pathogenesis of AD and reinforce the hypothesis that the neurodegenerative processes in the AD patients are associated with an abnormal antigen-specific immune response. The activation of immune system mechanisms observed in obsessive compulsive disorders could be due to the combination of endogenous (hormonal alterations associated to the modifications in the hypothalamic-pituitary-adrenal axis) and exogenous (viral or bacterial infections) factors.