<qa>  What is the first phase of the study?This is an investigator-initiated, single-site study, consisting of two phases: 8 weeks of open-label treatment with sertraline 50mg-150mgday in patients iwth OCD.At week 8, those who have failed to achieve remission will be continued on sertraline and will be randomized to receive Levetiracetam 500mg-2000mgday or Placebo for 8 weeks. 