Synaptic abnormalities have been implicated in schizophrenia. In order to investigate synaptic pathology in schizophrenia, we examined levels of mRNAs encoding synaptophysin, synapsin 1A and synapsin 1B in the left temporal cortex from schizophrenics (n = 24) and from normal control individuals with no history of psychiatric illness (n = 10). Levels of synaptic mRNAs in the left superior temporal and left middle temporal gyrus declined significantly with age in schizophrenics, but not in controls. Dividing the diagnostic groups according to age (below and above 75 years), the data revealed that in "young" schizophrenics (age <75 years) levels of the three synaptic mRNAs in the left superior and left middle temporal gyri were approximately two times higher than in the age-matched controls. In the "old" schizophrenics (age >75 years) the levels of synaptic mRNAs in temporal cortex did not differ from age-matched controls. These findings further support the hypothesis that developmental synaptic abnormalities may be involved in the pathophysiology of schizophrenia.