Figure 1.

Study flow diagram. Articles were excluded if they met any one of the following criteria: 1) were not an empirical study; (2) did not involve human subjects; (3) did not include a measure of PA or a positive mood manipulation (e.g., humorous films, pleasant images); (4) used a reversed indicator of negative affect (NA) as a measure of PA (e.g., hopelessness versus hopefulness; pessimism versus optimism; fatigue versus vigor/vitality); (5) did not include a subjective or objective measure of pain severity; (6) assessed affect only in regard to a specific life experience (e.g., “How happy are you about being pregnant?”); (7) examined only the directional effect of pain on PA or mean differences in PA between pain impaired and non-impaired samples; (8) did not enroll individuals identified as suffering from chronic pain; (9) assessed acute or induced pain; (10) did not employ an eligible study design; (11) did not examine or report a directional effect of PA on pain; (12) exclusively used a sample of patients with a primary cancer diagnosis; (13) were published in languages other than English; (14) did not include adults (18 years and above); (15) exclusively used a sample of patients presenting with a primary psychological disorder; (16) did not directly target PA; (17) did not include full quantitative results on outcomes; (18) full text of article could not be located; or (19) were a duplicate identified during full-text screening.