Figure 3: Number of recovered, improved, unchanged, and deteriorated
patients at the end of therapy based on the Reliable Change Index
classification (RCI) in both trauma groups. Error bars represent
standard deviations between the imputed data sets. Most patients
recovered, with no significant differences between the trauma groups.
Differences between the Depression
Groups
According to Hypothesis 2c, we tested for differences in the effect of
trauma on symptom severity over time between patients diagnosed with and
without a depression disorder.
For the BAI, adding the depression factor did not improve the model
(F (1, 2,723.98) < 0.01, p = .986), neither did
the interaction effect between depression and trauma (F (1,
2,975.45) = 0.73, p = .393), depression and time point
(F (1, 723.22) = 0.75, p = .388) or depression, trauma and
time point (F (1, 937.24) = 0.27, p = .606). Results
indicate no differences in the BAI scores or trajectories and no
differences in the effect of the trauma group on BAI scores between the
depression groups; see also Supplemental Figure 6.
For the BDI-II, adding the depression factor (F (1, 1,633.38) =
22.27, p < .001) significantly improved the model, but
adding the interaction effect between depression and trauma (F (1,
4,536.77) = 0.21, p = .645) and between depression, trauma and
time point (F (1, 1,106.90) = 0.47, p = .494) did not,
indicating no evidence for differences in the effect of the trauma group
on BDI-II scores between the depression groups. More detailed
information on the effects of depression over time on BDI-II scores is
given in the Supplemental Material.
Differences between the Trauma
Subtypes
Differences in the impact of interpersonal, non-interpersonal, and no
trauma on symptom severity over time were tested according to Hypothesis
3 using the interpersonal trauma index instead of the global trauma
index. Adding the interpersonal trauma factor did not improve the models
for anxiety and depression symptoms (BAI: F (2, 542.09) = 1.92,p = .148, BDI-II: F (2, 1,503.24) = 2.69, p = .068),
nor did the interaction effect between interpersonal trauma and time
point (BAI: F (2, 237.55) = 1.15, p = .319, BDI-II:F (2, 490.63) = 1.38, p = .254), indicating no differences
in symptom severity or trajectories between patients with interpersonal
trauma, non-interpersonal trauma only and no trauma, see Supplemental
Figure 7.
Effects of Trauma-specific
Interventions
In an exploratory analysis in line with the not preregistered Hypothesis
4, adding the factor trauma-specific intervention (none or at least one)
did not improve the model for depression or anxiety severity (BAI:F (1, 4,936.26) = 0.27, p = .602, BDI-II: F (1,
3,584.34) = 0.01, p = .931), neither did adding the interaction
effect between trauma-specific intervention and trauma (BAI: F (1,
6,180.62) = 0.69, p = .405, BDI-II: F (1, 4,754.02) = 0.01,p = .943), trauma-specific intervention and time point (BAI:F (1, 1,123.00) = 0.24, p = .624, BDI-II: F (1,
1,311.98) = 3.13, p = .077) or trauma-specific intervention,
trauma and time point (BAI: F (1, 979.65) = 0.73, p = .392,
BDI-II: F (1, 1,388.50) < 0.01, p = .995). This
indicates no significant differences between groups with and without
trauma-specific intervention in the overall symptom severity and the
decrease in symptom severity, regardless of trauma history, see Figure
4.