Although PDE10A inhibitors attract considerable interest as a potential target for the treatment of neuropsychiatry [38,39] and movement disorders such as Huntington’s disease (HD) [40] advancing to early clinical safety studies, PDE10A inhibitors from three companies failed to evidence antipsychotic activity in patients with schizophrenia, and a phase-II study conducted by Pfizer showed no efficacy to improve symptoms in patients with HD [41]. This evidence concerns the gene PDE10A and movement disorder.