Dube MO, Langevin P, Roy JS Measurement properties of the Pain Self-Efficacy Questionnaire in populations with musculoskeletal disorders: a systematic review. Pain Rep. 2021 Dec 21;6(4):e972. doi: 10.1097/PR9.0000000000000972. eCollection 2021 Nov-Dec.
Finch AP, Brazier JE, Mukuria C What is the evidence for the performance of generic preference-based measures? A systematic overview of reviews. Eur J Health Econ. 2018 May;19(4):557-570. doi: 10.1007/s10198-017-0902-x. Epub 2017 May 30.
Haefeli M, Elfering A Pain assessment. Eur Spine J. 2006 Jan;15 Suppl 1(Suppl 1):S17-24. doi: 10.1007/s00586-005-1044-x. Epub 2005 Dec 1.
Plummer F, Manea L, Trepel D, McMillan D Screening for anxiety disorders with the GAD-7 and GAD-2: a systematic review and diagnostic metaanalysis. Gen Hosp Psychiatry. 2016 Mar-Apr;39:24-31. doi: 10.1016/j.genhosppsych.2015.11.005. Epub 2015 Nov 18.
Spitzer RL, Kroenke K, Williams JB, Lowe B A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med. 2006 May 22;166(10):1092-7. doi: 10.1001/archinte.166.10.1092.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
