The invention relates to the finding that turnover of DISC1 (Disrupted in schizophrenia 1) is mediated by the F-box-containing protein FBXW7 (F-box/WD repeat-containing protein 7). The sequence within DISC1 that binds to FBXW7 and targets DISC1 for turnover by the ubiquitin-proteasome system is identified. The invention provides antagonists that inhibit this interaction and methods of using these antagonists to decrease DISC1 turnover, for example in treatment of neuropsychiatric disorders, as well as methods of identifying new antagonists.