Background: Schizophrenia is a neurodevelopmental disorder with onset early in adulthood. Disrupted-In-Schizophrenia-1 (DISC1) is a susceptibility gene for schizophrenia and other psychiatric disorders. Disc1-L100P mutant mice show behaviors relevant to schizophrenia at 12 weeks, but not at 8 weeks of age, and may be useful for investigating the onset of schizophrenia in early adulthood. Methods: We investigated whether early valproic acid treatment would prevent behavioral, cellular and gene expression abnormalities in Disc1-L100P mutants. Results: Valproic acid prevented hyperactivity and deficits in prepulse inhibition and latent inhibition in Disc1-L100P mice. Genome-wide transcription profiling identified Lcn2 (lipocalin2) transcripts as being elevated by the Disc1 mutation and corrected by valproate. Disc1-L100P mice also had increased glial cell numbers in the subventricular zone, which was normalized by valproate. Genetic deletion of Lcn2 normalized glial cell numbers and behavior in Disc1-L100P mutants. Conclusions: Pharmacological treatments are a feasible way of preventing abnormal behaviour in a genetic model of