قرار گرفتن در معرض درون اینترنت و فعالسازی رفتاری برای سوگ و عزاداری و نشخوار فکری: مطالعه کنترل شده تصادفی

Abstract This study examined the effectiveness and feasibility of therapist-guided Internet-delivered exposure (EX) and behavioral activation (BA) for complicated grief and rumination. Forty-seven bereaved individuals with elevated levels of complicated grief and grief rumination were randomly assigned to three conditions: EX (N = 18), BA (N = 17), or a waiting-list (N = 12). Treatment groups received 6 homework assignments over 6 to 8 weeks. Intention-to-treat analyses showed that EX reduced complicated grief, posttraumatic stress, depression, grief rumination, and brooding levels relative to the control group at posttreatment (d = 0.7–1.2). BA lowered complicated grief, posttraumatic stress, and grief rumination levels at posttreatment (d = 0.8–0.9). At 3-month follow-up, effects of EX were maintained on complicated grief and grief rumination (d = 0.6–1.2), and for BA on complicated grief, posttraumatic stress, and grief rumination (d = 0.8–0.9). EX reduced depression more strongly than BA (d = 0.6). Completers analyses corroborated results for EX, and partially those for BA, but no group differences were detected. BA suffered from high dropout (59%), relative to EX (33%) and the waiting-list (17%). Feasibility appeared higher for EX than BA. Results supported potential applicability of online exposure but not behavioral activation to decrease complicated grief and rumination.

Results Preliminary analyses Randomization Check Before conducting the main analyses, we performed a randomization check by comparing all groups at baseline on all variables using chi-square tests and ANOVAs. No baseline group differences were found on demographic and loss-related variables, or on levels of complicated grief, posttraumatic stress, anxiety, grief rumination and reflection. However, we did find significant baseline differences between groups on depressive symptoms, F(2, 44) = 3.49, p = .04, and brooding, F(2, 44) = 5.26, p = .01. Post-hoc tests revealed that the behavioral activation group scored higher on depressive symptoms, t(27) = 2.44, p = .02, d = 0.9, and brooding than the control group, t(27) = 2.96, p = .01, d = 1.1, and higher on brooding than the exposure group, t(33) = 2.12, p = .04, d = 0.7. Depressive symptoms and brooding were therefore used as covariates in the main analyses comparing behavioral activation against the control group, and brooding was used as a covariate in main analyses comparing exposure against behavioral activation. Dropout and Nonresponse If participants in the treatment groups completed less than 4 homework assignments, they were regarded as dropouts. In total, a notable 10 out of 17 participants (58.8%) dropped out during treatment in the behavioral activation group, and 6 out of 18 (33.3%) in the exposure group. Figure 1 shows the flowchart with reasons for dropout. Nonresponse rates were as follows: Three out of 18 participants (16.7%) in the exposure condition did not complete the post-test, and 6 (33.3%) did not complete the follow-up. Six out of 17 participants (35.3%) in the behavioral activation condition and 2 out of 12 participants (16.7%) in the waiting-list condition did not fill out postmeasurement and follow-up questionnaires. We found no differences between completers and dropouts on demographic and loss-related variables, or symptom and rumination levels. Although dropout appeared highest in the behavioral activation group, a chi-square test did not indicate a significant group difference on dropout, χ2(2) = 3.95, p = .14. Feasibility All participants who filled out the postmeasurement were included in our feasibility analysis, that is, 15 people from the exposure group (12 completers) and 11 people from the behavioral activation group (7 completers). Participants in the exposure condition indicated that they understood the study information (Mean = 4.67 , SD = 0.60, agree/strongly agree = 93.3%) and homework assignments (Mean = 4.67, SD = 0.48, agree/strongly agree = 100.0%). They also reported that their therapist understood them (Mean = 4.36, SD = 0.63, agree/strongly agree = 92.9%). A majority of participants in this group agreed that the treatment was useful (Mean = 4.00, SD = 1.17, agree/strongly agree = 64.3%), feasible (Mean = 4.21, SD = 1.05, agree/strongly agree = 85.7%), and satisfactory (Mean = 3.86, SD = 0.95, agree/strongly agree = 64.3%). Behavioral activation participants also reported that they understood study information (Mean = 4.64, SD = 0.51, agree/strongly agree = 100.0%) and homework assignments (Mean = 4.27, SD = 0.78, agree/strongly agree = 81.8%). They also indicated that their therapist understood them (Mean = 4.13, SD = 0.94, agree/strongly agree = 81.8%). However, people in the behavioral activation group did not consistently agree with the statements that the treatment was useful, feasible and satisfactory (all Means = 3.64, SD’s = 1.21, agree/strongly agree = 45.5%, 63.6%, 45.5%, respectively). This is noteworthy, particularly since 6 participants from the behavioral activation group were not included in these analyses, 4 of whom discontinued treatment because they found the assignments too difficult or time-consuming (see Figure 1). Despite a moderate effect, a significant group difference on feasibility was not detected, t(23) = 1.08, p = .29, d = 0.5. Main analyses Intention-to-Treat Analyses Table 2, Table 3 and Table 4 show the intention-to-treat multilevel regression analyses on the data from all participants who were initially allocated to one of our three groups. The tables with observed means and standard deviations and corresponding within- and between-group effect sizes are available as an online supplement. Table 2. Multilevel Regression Intention-to-Treat Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and 3-Month Follow-Up (Model 2) Exposure Versus Control Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 57.17 (5.23)** 37.67 (2.13)** 8.75 (1.31)** 11.00 (1.11)** 43.5 (2.56)** 9.83 (0.83)** 9.08 (0.79)** Time (T1 vs. T2) 1.99 (4.69) 1.85 (1.88) 0.11 (1.09) 0.274 (0.87) 0.56 (3.05) 1.40 (0.70)* 0.02 (0.77) Between Group (Ex vs. Co) 5.11 (6.76) -0.33 (2.75) 2.36 (1.69) -0.06 (1.43) 2.61 (3.31) 1.44 (1.08) 1.92 (1.01) Time × Group -14.42 (6.06)* -7.18 (2.43)** -3.20 (1.41)* -2.10 (1.12)† -9.59 (3.94)* -3.02 (0.90)** -1.16 (1.00) Model 2 Within Constant 57.17 (5.15)** 37.67 (2.12)** 8.75 (1.27)** 11.00 (1.17)** 43.5 (2.29)** 9.83 (0.78)** 9.08 (0.75)** Time (T1 vs. T3) -2.20 (2.31) -1.35 (1.05) -1.17 (0.46)* -0.56 (0.50) -2.08 (1.19) -0.33 (0.42) 0.30 (0.40) Between Group (Ex vs. Co) 5.11 (6.65) -0.33 (2.74) 2.36 (1.64) -0.06 (1.51) 2.61 (2.97) 1.44 (1.01) 1.92 (0.96) Time × Group -6.15 (3.11)* -1.96 (1.41) -0.68 (0.62) -0.87 (0.68) -4.83 (1.60)** -1.07 (0.56)† -1.25 (0.53)* Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up. Ex = exposure therapy. Co = waiting list control group. ** = p < .01, * = p < . 05, † = p < .10. Table options Table 3. Multilevel Regression Intention-to-Treat Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and Follow-Up (Model 2) Behavioral Activation Versus Control Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 66.22 (4.17)** 42.04 (1.87)** 10.27 (1.18)** 13.11 (1.06)** 47.78 (2.47)** 10.93 (0.86)** 10.08 (0.65)** Time (T1 vs. T2) -1.68 (1.96) 1.07 (0.94) 1.15 (0.45)* -0.49 (0.43) -1.88 (1.12) -0.26 (0.42) -0.24 (0.32) Between Brooding T1 1.26 (0.83) 0.54 (0.37) 0.58 (0.23)* 0.59 (0.21)** 0.76 (0.49) - - 0.24 (0.13)* Depression T1 2.35 (0.60)** 1.04 (0.27)* - - 0.31 (0.16)* 0.89 (0.36)* 0.28 (0.12)* 0.18 (0.09)* Group (Ba vs. Co) -1.57 (5.76) -2.26 (2.58) 1.29 (1.63) 1.35 (1.47) -0.90 (3.41) 1.75 (1.15) 0.47 (0.89) Time × Group -7.16 (2.68)** -3.48 (1.28)** 0.12 (0.62) -1.04 (0.59)† -3.92 (1.54)* -0.61 (0.58) -0.96 (0.45)* Model 2 Within Constant 65.11 (3.98)** 41.00 (1.81)** 9.87 (1.15)** 13.00 (1.05)** 46.92 (2.39) 10.42 (0.80)** 9.95 (0.69)** Time (T1 vs. T3) -1.67 (1.90) -0.97 (1.03)** 1.15 (0.36)** -0.48 (0.46) -1.96 (0.93)* -0.29 (0.39) -0.25 (0.38) Between Brooding T1 1.38 (0.78) 0.49 (0.34) 0.56 (0.22)* 0.61 (0.21)** 0.87 (0.48) - - 0.19 (0.09)* Depression T1 2.34 (0.57) 1.07 (0.25)** - - 0.36 (0.15)* 0.77 (0.36)* 0.26 (0.11) 0.22 (0.13) Group (Ba vs. Co) 0.08 (5.49) -1.11 (2.48) 1.88 (1.57) -1.29 (1.45) -0.04 (3.31) 2.41 (1.08)* 0.67 (0.95) Time × Group -7.16 (2.60)** -3.40 (1.40)* 0.12 (0.50) -1.04 (0.63)† -3.80 (1.28)** -0.57 (0.54) -0.95 (0.52)† Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up measurement. Ba = behavioral activation. Co = waiting list control group. ** = p < .01, * = p < . 05, † = p < .10. Table options Table 4. Multilevel Regression Intention-to-Treat Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and 3-Month Follow-Up (Model 2) Exposure Versus Behavioral Activation Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 70.48 (3.52)** 41.96 (1.49)** 12.28 (0.74)** 12.85 (0.79)** 49.16 (2.17)** 13.11 (0.61) 10.89 (0.51)** Time (T1 vs. T2) -9.12 (2.23)** -4.45 (0.94)** -1.04 (0.46)* -1.53 (0.40)** -5.89 (1.39)** -0.87 (0.37)* -1.19 (0.33)** Between Brooding T1 -0.56 (0.85) 0.27 (0.36) 0.10 (0.18) 0.27 (0.20) 0.20 (0.53) - - 0.37 (0.12)** Group (Ex vs. Ba) -8.85 (5.17)† -4.32 (2.19)* -1.05 (1.09) -1.60 (1.15) -2.81 (3.20) -1.83 (0.86)* 0.52 (0.75) Time × Group -3.06 (4.53) -0.67 (1.92) -2.13 (0.94)* -0.25 (0.80) -3.12 (2.81) 0.77 (0.76) 0.08 (0.70) Model 2 Within Constant 71.14 (3.54)** 41.93 (1.49)** 12.38 (0.76)** 12.78 (0.77)** 48.99 (2.04)** 13.24 (0.57)** 10.83 (0.51)** Time (T1 vs. T3) -9.17 (2.13)** -4.33 (0.98)** -1.01 (0.47)* -1.52 (0.44)** -5.87 (1.19)** -0.88 (0.39)* -1.18 (0.34)** Between Brooding T1 0.38 (0.84) 0.30 (0.35) 0.15 (0.18) 0.33 (0.19)† 0.30 (0.50) - - 0.40 (0.12)** Group (Ex vs. Ba) -9.22 (5.08)† -4.31 (2.14)* -1.13 (1.09) -1.52 (1.10) -2.59 (2.93) -1.96 (0.80)* 0.55 (0.74) Time × Group 1.17 (3.21) 1.21 (1.36) -0.88 (0.65) 0.12 (0.60) -1.02 (1.66) 0.55 (0.54) -0.38 (0.47) Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up. Ex = exposure therapy. Ba = behavioral activation. ** = p < .01, * = p < . 05, † = p < .10. Table options Treatment Effects for Exposure Therapy at Posttest and Follow-up At postmeasurement, between-group interaction effects (Time × Group) showed that exposure reduced symptoms of complicated grief (p = .02, d = 0.8), posttraumatic stress (p = .003, d = 1.0) and depression (p = .03, d = 0.7), and levels of grief rumination (p = .02, d = 1.2) and depressive brooding (p < .001, d = 1.0), compared to the control group. No significant interaction effects were found for anxiety (p = .06, d = 0.4) and depressive reflection (p = .25, d = 0.3). At follow-up measurement, between-group interaction effects (Time × Group) showed that treatment effects of exposure therapy were maintained for complicated grief symptoms (p = .048, d = 0.6) and grief rumination (p = .003, d = 1.2). Additionally, a significant interaction effect was found on depressive reflection (p = .02, d = 0.8). However, no significant effects emerged for levels of posttraumatic stress (p = .16, d = 0.5), depression (p = .27, d = 0.2), anxiety (p = .20, d = 0.4) and depressive brooding (p = .056, d = 0.7). Treatment Effects for Behavioral Activation at Posttest and Follow-up Behavioral activation showed significant between-group interaction effects (Time × Group) for symptom levels of complicated grief (p = .008, d = 0.9) and posttraumatic stress disorder (p = .003, d = 0.8), and for grief rumination (p = .01, d = 0.8) and depressive reflection (p = .03, d = 0.5). However, behavioral activation did not significantly ameliorate depression (p = .57, d = 0.3), anxiety (p = .08, d = 0.5) or depressive brooding (p = .29, d = 0.8). Effects for behavioral activation were maintained at follow-up for symptoms of complicated grief (p = .003, d = 0.9) and posttraumatic stress disorder (p = .02, d = 0.8) and grief rumination levels (p = .003, d = 0.9). No significant interaction effects were found for symptom levels of depression (p = .40, d = -0.2) and anxiety (p = .10, d = 0.5), and depressive reflection (p = .07, d = 0.6) and depressive brooding (p = .29, d = 0.3). Exposure Versus Behavioral Activation at Posttest and Follow-up Only one difference between exposure and behavioral activation was detected: at posttest, exposure had resulted in stronger reductions in depressive symptoms than behavioral activation (p = .02, d = 0.6). Other differences on dependent variables at posttest and follow-up were negligible to small (d’s = 0.05-0.42), and failed to reach statistical significance. Completer analyses Table 5, Table 6 and Table 7 show the completer's multilevel regression analyses. That is, analyses performed on the data from all participants who were initially allocated to one of our three groups, excluding treatment dropouts. The completer means and standard deviations and corresponding within- and between-group effect sizes are available as an online supplement. Table 5. Multilevel Regression Completers Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and 3-Month Follow-Up (Model 2) Exposure Versus Control Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 58.30 (5.92)** 38.40 (2.51)** 8.10 (1.46)** 10.90 (1.27)** 43.60 (2.84)** 9.50 (0.93)** 8.90 (0.88)** Time (T1 vs. T2) 1.60 (4.81) (4.81) 1.60 (1.87) 0.30 (1.11) 0.30 (0.73) 0.50 (3.04) 1.50 (0.68)* 0.10 (0.83) Between Group (Ex vs. Co) 3.70 (8.02) 0.35 (3.44) 2.31 (1.97) 0.60 (1.72) 3.82 (3.84) 2.50 (1.25) 2.43 (1.19)* Time × Group -17.52 (6.51)** -8.60 (2.53)** -3.80 (1.51)* -3.30 (0.98)** -12.00 (4.12)** -3.42 (0.92)** -1.52 (1.13) Model 2 Within Constant 58.30 (6.00)** 38.40 (2.55)** 8.10 (1.43)** 10.90 (1.43)** 43.60 (2.54)** 9.50 (0.85)** 8.90 (0.85)** Time (T1 vs. T3) -2.40 (2.36) -1.50 (1.08) -1.10 (0.46)* -0.55 (0.52) -2.10 (1.17)† -0.25 (0.43) -0.25 (0.42) Between Group (Ex vs. Co) 4.80 (8.49) 0.50 (3.60) 2.70 (2.02) 0.40 (2.02) 4.10 (3.59) 2.30 (1.19)† 2.30 (1.20)† Time × Group -7.35 (3.34)* -2.75 (1.52)† -1.00 (0.65) -1.20 (0.74) -5.75 (1.64)** -1.25 (0.61)* -1.35 (0.60)* Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up. Ex = exposure therapy. Co = waiting list control group. ** = p < .01, * = p < . 05, † = p < .10. Table options Table 6. Multilevel Regression Completers Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and Follow-Up (Model 2) Behavioral Activation Versus Control Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 65.96 (4.35)** 41.36 (1.94)** 8.79 (1.34)** 12.00 (1.06)** 47.05 (2.23)** 10.37 (0.14)** 9.45 (0.73)** Time (T1 vs. T2) 1.60 (3.26) 1.60 (1.77) 0.30 (0.82) 0.30 (0.55) 0.500 (1.87) 1.50 (0.74)* 0.10 (0.63) Between Brooding T1 1.26 (1.13) 0.87 (0.49)† 0.77 (0.33)* 0.29 (0.29) 0.40 (0.57) - - 0.16 (0.18) Depression T1 2.98 (0.76)** 1.00 (0.33)** - - 0.39 (0.19)* 1.41 (0.38) 0.40 (0.14)** 0.19 (0.12) Group (Ba vs. Co) -7.50 (7.31) -0.32 (3.25) 3.64 (2.16)† 0.56 (1.79) 0.00 (3.74) 1.96 (1.53) 1.47 (1.21) Time × Group -9.17 (5.07)† -6.74 (2.77)* -1.59 (1.27) 1.87 (0.86)* -5.07 (2.91)† -2.79 (1.15)* -2.10 (0.98)* Model 2 Within Constant 66.73 (4.71)** 41.78 (1.97) 9.34 (1.32)** 12.46 (1.22)** 47.10 (2.50)** 10.24 (0.83)** 9.48 (0.77)** Time (T1 vs. T3) -2.40 (1.97) -1.50 (1.11) -1.10 (0.30)** -0.55 (0.49) -2.10 (0.94)* -0.25 (0.41) -0.25 (0.42) Between Brooding T1 1.42 (1.16) 0.60 (0.44) 0.75 (0.31)* 0.27 (0.30) 0.84 (0.63) - - 0.17 (0.17) Depression T1 2.76 (0.78)** 1.09 (0.30)** - - 0.50 (0.20)* 0.95 (0.42)* 0.34 (0.12)** 0.14 (0.12) Group (Ba vs. Co) -9.36 (8.11) -1.33 (3.34) 2.28 (2.27) -0.55 (2.10) -0.10 (4.32) 2.28 (1.38) 1.40 (1.30) Time × Group -5.67 (3.07)† -3.86 (1.73)* 0.03 (0.47) -1.09 (0.77) -4.19 (1.47)** -0.82 (0.64) -1.18 (0.65)† Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up measurement. Ba = behavioral activation. Co = waiting list control group. ** = p < .01, * = p < . 05, † = p < .10. Table options Table 7. Multilevel Regression Completers Analyses: Time and Interaction Effects (Time x Group) at Post-Measurement (Model 1) and 3-Month Follow-Up (Model 2) Exposure Versus Behavioral Activation Group CG PTSD Depression Anxiety Grief rumination Brooding Reflection b (SE) b (SE) B (SE) b (SE) b (SE) b (SE) b (SE) Model 1 Within Constant 62.34 (3.17)** 39.00 (1.82)** 10.55 (0.85)** 11.51 (0.86)** 47.22 (2.51)** 12.00 (0.68)** 11.51 (0.66)** Time (T1 vs. T2) -15.91 (4.62)** -7.00 (2.09)** -3.500 (0.89)** -3.00 (0.62)** -11.50 (2.98)** -1.92 (0.77)* -1.42 (0.81)† Between Brooding T1 0.59 (1.09) 0.43 (0.52) 0.23 (0.26) 0.03 (0.28) -0.34 (0.71) - - 0.30 (0.18) Group (Ex vs. Ba) 6.51 (5.40) 5.85 (3.07)† 2.65 (1.44)† 2.60 (1.47)† 5.11 (4.22) 1.57 (1.12) -0.09 (1.11) Time × Group 8.35 (7.61) 1.86 (3.44) 2.21 (1.47) 1.43 (1.02) 6.93 (4.90) 0.63 (1.27) -0.58 (1.33) Model 2 Within Constant 70.27 (5.78)** 45.14 (2.31)** 13.36 (1.08)** 14.23 (1.18)** -6.29 (1.59)** 13.57 (0.80)** 11.44 (0.86)** Time (T1 vs. T3) -8.07 (3.28)* -5.35 (1.38)** -1.07 (0.58)† -1.64 (0.60)** -4.76 (4.08) -1.07 (0.54)* -1.43 (0.50)** Between Brooding T1 -0.81 (1.40) 0.14 (0.55) 0.07 (0.27) -0.08 (0.30) -0.26 (0.77) - - 0.26 (0.21) Group (Ex vs. Ba) -7.76 (7.71) -6.13 (3.08)* -2.51 (1.44)† -3.00 (1.57)† -4.76 (4.08) -1.77 (1.04) -0.05 (1.15) Time × Group -1.68 (4.28) 1.11 (1.79) -1.03 (0.76) -0.11 (0.78) -1.56 (2.07) -0.43 (0.70) -0.17 (0.65) Note. CG = complicated grief. PTSD = posttraumatic stress disorder. T1 = baseline measurement. T2 = post-measurement. T3 = three month follow-up. Ex = exposure therapy. Ba = behavioral activation. ** = p < .01, * = p < . 05, † = p < .10. Table options Treatment Effects for Exposure at Posttest and Follow-up At postmeasurement, significant interaction effects (Time × Group) were found for exposure on levels complicated grief (p = .007, d = 0.8), posttraumatic stress (p < .001, d = 1.1), depression (p = .01, d = 0.7), and anxiety (p < .001, d = 0.7), grief rumination (p = .004, d = 1.4), and depressive brooding (p < .001, d = 1.1), but not reflection (p = .18, d = 0.5). At follow-up, effects of exposure were maintained for complicated grief (p = .03, d = 0.7), grief rumination (p < .001, d = 1.4), and depressive brooding (p = .04, d = 0.8). Additionally, an interaction effect was found on depressive reflection (p = .02, d = 0.9). However, despite moderate effect sizes, no interaction effects were found for three other variables that were significantly reduced at posttreatment: symptoms of posttraumatic stress (p = .07, d = 0.7), depression (p = .13, d = 0.4), and anxiety (p = .10, d = 0.5). Treatment Effects for Behavioral Activation at Posttest and Follow-up Whereas the completer analyses of exposure therapy corresponded with the findings of the intention-to-treat analyses, results were less consistent for behavioral activation. At postmeasurement, significant interaction effects were found on posttraumatic stress (p = .02, d = 0.9), anxiety (p = .03, d = 0.4), depressive brooding (p = .02, d = 0.8), and depressive reflection (p = .03, d = 0.8). No significant interaction effects were detected for complicated grief (p = .07, d = 0.4), grief rumination (p = .08, d = 0.5), and depression (p = .21, d = 0.2). At follow-up, the effects of behavioral activation were maintained for posttraumatic stress symptoms (p = .03, d = 1.1) and behavioral activation also significantly reduced grief rumination (p = .004, d = 1.0). However, despite moderate to large effect sizes, no significant interaction effects emerged at 3-month follow-up for complicated grief (p = .06, d = 0.6), anxiety (p = .16, d = 0.4), depressive brooding, (p = .20, d = 0.5), and depressive reflection (p = .07, d = 0.9). No effect was found for depression (p = .95, d = 0.0). Exposure Versus Behavioral Activation at Posttest and Follow-up No significant Time × Group interaction effects were detected when comparing exposure and behavioral activation at posttest and 3-month follow-up. Nevertheless, moderate to large interaction effects in favor of exposure were observed for complicated grief (p = .27, d = 0.7), depression (p = .13, d = 0.8), anxiety (p = .16, d = 0.5), and grief rumination (p = .16 , d = 0.9) at posttest. At follow-up, behavioral activation appeared more effective in reducing posttraumatic stress (p = .53, d = 0.6), and exposure in reducing depression (p = .17, d = 0.6). All other effects were small (d’s = 0.17–0.43). Clinical change As a measure of clinical change, we calculated a Reliable Change Index (RCI) by calculating what percentage of each group experienced a reduction in symptom scores larger than two times the baseline SE of measurement of a dependent variable (Jacobson & Truax, 1991). For these analyses we used the observed values for all participants for our main outcome measures: complicated grief and grief rumination. At posttest, 46.7% of participants in the exposure group, 45.5% of participants in the behavioral activation group, and 10.0% of people in the control group had achieved reliable change on complicated grief symptoms. At 3-month follow-up, 58.3% of participants in the exposure group, 63.6% of participants in the behavioral activation group, and 20.0% of people in the control group attained reliable change on complicated grief levels. Chi-square tests showed no significant differences in percentages of participants that attained reliable change between the exposure and control group at posttest, χ2(1) = 3.71, p = .054, and follow-up, χ2(2) = 3.32, p = .07, and between behavioral activation and the control group at posttest, χ2(1) = 3.23, p = .07, and follow-up, χ2(1) = 1.53, p = .22, or between the behavioral activation and exposure group at either measurement moment (p’s > .10). At posttest, 46.7% of the exposure group, 36.4% of the behavioral activation group, and 10.0% of the control group had achieved reliable change on grief rumination levels. At follow-up, 66.7% of the exposure group, 45.4% of the behavioral activation group, and 30.0% of the control group had attained reliable change on grief rumination. Chi-square tests showed no differences in percentages of participants who achieved reliable change between the exposure and control group at posttest, χ2(1) = 3.71, p = .054, and follow-up, χ2(1) = 2.93, p = .09, nor between behavioral activation and the control group and the behavioral activation and exposure group at either measurement moment (p’s > .10).