Synaptic imbalances in endogenous psychoses.

Based on the formalism of logical balance, imbalances of information processing in tripartite synapses are described as a possible explanation for the pathophysiology of endogenous psychoses like depression, mania and schizophrenia. A tripartite synapse consists of the presynapse, the synaptic cleft, the postsynapse (neuronal components) and the glia (glial components). According to the logic of balance in a living system, the number of values and the number of variables must be equal. In a tripartite synapse the neuronal components are interpreted as values, the glial components as variables. In line with this novel synaptic model, three elementary synaptic imbalances can be deduced. First, tripartite synapses are underbalanced if the variables outnumber the values. Such a system state may cause depression. Second, if the values outnumber the variables, the tripartite synapses are overbalanced which may be responsible for mania. Third, if no functional variables are available at all, tripartite synapses process information unbalanced which may cause schizophrenia. The basic symptoms of these psychobiological disorders can be deduced from this novel synaptic model.