The invention provides methods for the treatment of abnormal psychiatric states, particularly the negative symptoms of schizophrenia and extrapyramidal side effects (EPS) of antipsychotic drugs. The inventive methods relate to the administration of therapeutic cells (which produce dopamine or dopamine precursors) adhered to support matrices to subjects suffering from the negative symptoms of schizophrenia and/or EPS. The therapeutic cells may be coadministered with cells which protect the therapeutic cells from immune rejection and/or cells which produce neurotrophic factors which improve the viability of the therapeutic cells.