Advancing Research
Changing Lives


Several large, national multi-site studies have had a specific focus on COPCs. They are briefly summarized below.

MAPP Research Network

The ‘Multidisciplinary Approach to the Study of Chronic Pelvic Pain’ (MAPP) Research Network is a large study sponsored by the National Institutes of Health taking place at seven universities across the U.S. The study’s goal is to the uncover new insights into the underlying disease mechanisms, natural history and risk factors associated with the development of interstitial cystitis and chronic prostatitis (collectively termed ‘urologic chroinc pelvic pain syndrome, UCPPS), including understanding the co-relationship between UCPPS and non-urologic pain syndromes. Those of primary interest include fibromyalgia, irritable bowel syndrome, chronic fatigue syndrome, vulvodynia and migraine headache. The study has recruited over 1,000 participants. Currently in its second five-year phase, MAPP II broadly focuses on understandig predictors of symptom progression and resolution, as well as mechanism-based subgroups that respond differently to treatment.

For more information on the MAPP, including a list of publications that have resulted from the study to date, please visit:     


Funded by the National Institutes of Health in 2006, the ‘Orofacial Pain, Prospective Evaluation and Risk Assessment’ (OPPERA) study was led by William Maixner, PhD, DDS, now director of the Center for Translational Pain Medicine at Duke University, and took place at four universities across the US. OPPERA I sought to identify risk factors, clinical characteristics and genetic mechanisms that influence the development of chronic orofacial pain associated with temporomandibular disorders (TMD). Investigators enrolled and monitored over 2,700 men and women, 260 of whom developed TMD in the three-year follow-up period. Since OPPERA’s first publication in 2011, 20 papers summarizing the study’s expansive findings collectively demonstrate that TMD is a complex disorder with a biopsychosocial model of illness, and that it is no longer appropriate to regard TMD solely as a localized orofacial pain condition. 

OPPERA II – the second five-year phase of the study funded in 2012 – aimed to understand the factors that predict the transition from acute to chronic TMD, as well as the development of chronic overlapping pain conditions, including headache, low back pain, irritable bowel syndrome and widespread body pain.

To read a review summarizing many of the major findings of the OPPERA studies, please visit:

Complex Persistent Pain Conditions: Unique & Shared Pathways of Vulnerability

This large program project, also led by Dr. Maixner and the UNC Center for Neurosensory Disorders and funded in 2011 by the National Institutes of Health, expands on OPPERA I & II (summarized above) to specifically study four prevalent pain conditions that frequently co-occur with temporomandibular disorders, including vulvodynia, irritable bowel syndrome, episodic migraine and fibromyalgia. This project aims to identify risk factors, clusters and associated genetic variations that influence pain amplification and psychological distress in study participants that have two or more of these conditions.  

For additional information, please click here.

PAIN Repository

The Pain and Interoception Imaging Network (PAIN) Repository seeks to improve the understanding of the brain’s role in chronic pain states. In 2013, the National Institute of Drug Abuse and National Center for Complementary and Integrative Health provided a three-year grant to the UCLA Center for Neurobiology of Stress to pioneer the development of this first large repository of well characterized multimodal brain images from patients with various pain disorders, including those with chronic overlapping pain conditions. Currently, imaging data from those with fibromyalgia, chronic migraine headache, irritable bowel syndrome, vulvodynia and chronic low back pain are included. Fifteen participating sites in North America and Europe are participating in this groundbreaking project, which aims to collect and store standardized brain images of 1,000 well characterized patients, including standardized clinical, behavioral and genetic metadata. For more information, please visit: