Personalized medicine can be defined as the tailoring of therapies to defined subsets of patients based on their likelihood to respond to therapy or their risk of adverse events. This medical model is more established in oncology but personalized pain therapy is showing potential promise. Pharmacogenomics is of growing relevance to the pain field, for example cytochrome P450 2D6 (CYP2D6) polymorphisms with resulting variation in degree of CYP2D6 expression may affect codeine analgesia. Research using quantitative sensory testing is seeking to identify phenotypic subgroups of neuropathic pain patients with different underlying pain mechanisms. Imaging studies have suggested that genetic, environmental, mood, and injury-specific factors combine to produce a unique cerebral pain "signature." The search for central nervous system (CNS) biomarkers for chronic pain is ongoing.