PTSD severity:
As outlined in the hypotheses, it was predicted that a number o f independent variables (namely, post-traumatic negative appraisals and peritraumatic dissociation) would independently predict the severity o f PTSD symptomatology. Preliminary correlational analyses indicated that a number o f variables were not significantly related to the PTDS Severity scale or subscales, and were therefore not controlled for in further regression analyses (see appendix 11).
As the PTDS subscales were all highly correlated (see table 19) with one another, and with the PTDS total severity score, the total score was used in the multiple regression analyses.
Table 19: Correlations between PTDS Severity Subscales and Total Score
Severity: PTSD
Severity
R e-E xp erien cing A voidance A rou sal
PTSD P earson Correlation 1.00 Sig. (2-tailed)
R e-exp erien cing Pearson Correlation 0.78 1.00 Sig. (2-tailed) <0.001
A void ance Pearson Correlation 0.86 0.50 1.00 Sig. (2-tailed) <0.001 0.005
A rousal Pearson Correlation 0.89 0.67 0.71 1.00 Sig. (2-tailed) <0.001 <0.001 <0.001
A series o f multivariate analyses were completed using the PTDS Severity Score as the outcome variable. This was to assess the unique contributions o f peritraumatic dissociation and post-traumatic appraisals to the variance in PTSD severity, independent o f time since assault and mental health history. The regression analyses, and the unique contributions o f each independent variable {sr^ ’s) are shown in tables 20 and 22-24.
History o f mental health problems and time since assault: Relationship to PTSD severity As shown in table 20, time since assault and mental health history were both significantly associated with PTSD severity (accounting for 15% and 34% o f the variance respectively). These variables were therefore included with peritraumatic dissociation (PDEQ) and negative posttraumatic appraisals (PTCI) as independent variables in the multivariate regression analysis on PTSD severity. This enabled the contributions o f peritraumatic dissociation and appraisals to the variance in PTSD severity, independent o f time since assault and mental health history, to be determined. As tables 22-24 illustrate, time since assault, but not mental health history, continued to predict a significant proportion o f the variance (17%) in PTSD severity independently o f PTCI and PDEQ score.
Table 20: Proportion o f variance in PTSD severity predicted individually by dissociation (PDEQ), appraisals (PTCI), mental health history, and time since assault
IV ’s predicting severity Beta R \ Adjusted R :
Significance o f change (F and p-values)
Mental Health Pre- Assault alone
-0.38 0.15 0.11 F(l,27)=4.56, p=0.042
Time since assault alone -0.59 0.34 0 2 2 F(l,26)=13.58, p=0.001 PTCI alone 0.51 0 2 6 0 2 3 F(l,25)=8.92, p=0.006
PDEQ alone 0.50 0 2 5 0 2 2 F(l,26)=8.55 p=0.007
Relationship between perceived amnesia Cmemory gaps’) and PTSD severity
Perceived extent o f amnesia in recent weeks was not significantly correlated with PTSD severity (r = 0.058, p = 0.767), and neither was completeness o f verbal narrative (r = 0.249, p = 0.192), or consciousness at the time o f the assault (r = 0.21, p = 0.27). Perceived severity o f amnesia was also not significantly correlated with post-traumatic appraisals (PTCI: r = 0.11, p = 0.59) or peritraumatic dissociation (PDEQ: r = 0.09, p = 0.64). These variables were therefore not included in the regression analyses.
Dissociation (PDEQ) and cognitive appraisals (PTCI): Relationship to PTSD
Posttraumatic negative appraisals (PTCI) will be positively associated with PTSD
It was hypothesised that posttraumatic appraisals, as assessed by the PTCI, would independently predict a significant proportion o f the variance in PTSD symptom severity for drug-rape survivors. A correlational analysis was conducted for the PTCI scales. This revealed that all items were moderately-highly inter-correlated (see table 21 for a summary). For this reason, the total PTCI score was used in the regression analyses.
Table 21: Inter-correlations between PTCI sub-scales PTCI Subscale: Pearson’s r Sum of Self Blame Sum of World Negative Cognitions Sum of Self Negative Cognitions Total PTCI Score
Self blame Pearson Correlation 1.00 Sig. (2-tailed) Negative cognitions about world Pearson Correlation 0.38 1.00 Sig. (2-tailed) 0.05 Negative cognitions about self Pearson Correlation 0.48 0.52 1.00 Sig. (2-tailed) 0.01 0.005
Sum of PTCI Sub- Scales
Pearson Correlation 0.65 0.70 0.96 1.00
Sig. (2-tailed) <0.001 <0.001 <0.001
Posttraumatic negative appraisals (PTCI) accounted for a significant proportion (23%) o f the variance in PTSD severity (see table 20). Although, as hypothesised, PTCI score was positively associated with PTSD severity, negative posttraumatic appraisals predicted the variance in PTSD severity at below significance when the independent effects o f time and mental health history on PTSD were partialled out, predicting only 9.4% o f the variance. The regression analysis is summarised in table 22.
Table 22: Regression analysis on PTSD severity: Cognitive appraisals (PTCI), time since assault and mental health history
IV ’s predicting severity Beta t-statistic F- statistic p-value r V Adjusted R r sr ' Model — — F(3,22) = 6.63 0.002 0.48 0.40 —
Mental Health Pre assault
-0.17 1.07 — 0.30 — — 0.029
Time since assault -0.41 2.43 — 0.24 — — 0.141
PTCI 0 J 5 1.98 — 0.60 — — 0.094
Peritraumatic dissociation (PDEQ) will be positively associated with PTSD severity As hypothesised, dissociation was positively associated with PTSD severity. Table 20 illustrates that, as the only independent variable, peritraumatic dissociation accounted for 25% o f the variance in PTSD severity. PDEQ score also predicted a significant proportion o f the variance (18%) in PTSD severity, independent o f time since assault and mental health history. The regression analysis is summarised in table 23.
Table 23: Regression analysis on PTSD severity: Dissociation (PDEQ), time since assault and mental health history
IV’s predicting severity Beta t-statistic F- statistic p-value R^ Adjusted R^ sr V Model — — F(3,23)= 11.03 <0.01 0.59 0.54 -- Mental Health Pre-assault -0.14 0.98 — 0.34 — - - 0.02
Time since assault -0.56 4.09 — <0.001 — — 0.30
Posttraumatic appraisals and dissociation: Relationship with PTSD severity
It was hypothesised that both dissociation (PDEQ) and posttraumatic appraisals (PTCI) would account for a significant proportion o f the variance in PTSD severity, independently o f each other. The independent variables posttraumatic appraisals (PTCI) and peritraumatic dissociation (PDEQ) were not significantly correlated (r =0.107, p = 0.595). To test this hypothesis further, all independent variables were entered together into a multiple regression analysis to assess their independent associations with PTSD severity (sr^’s). The results o f the regression are summarised in table 24.
Table 24: Regression analysis on PTSD severity, with all independent variables entered (dissociation (PDEQ), cognitive appraisals (PTCI), time since assault and
mental health history) IV ’s predicting severity Beta t-statistic F- statistic p-value Adjusted R : sr* Model (total) - - — F(4,22) = 9 3 2 0.0002 0.64 0.57 - Mental Health Pre-assault -0.092 0.67 — 0.51 — 0.008
Time since assault -0.45 3.17 — 0.005 — — 0.17
PTCI 0.29 1.94 — 0.066 — 0.065
PDEQ 0.42 3.10 — 0.005 — — 0.17
As hypothesised, peritraumatic dissociation (PDEQ) independently predicted a significant proportion o f the variance in PTSD severity (17%) when appraisals (PTCI) were included in the regression analysis. However, the proportion o f the variance in PTSD independently accounted for by negative posttraumatic appraisals (PTCI) reduced to 6.5%, which was not statistically significant. It is possible that the below significance
error).
The multiple regression analysis on PTSD severity with all predictor variables entered is summarised in figure 10 below.
Figure 10: Summary of the relationship of negative appraisals and dissociation with PTSD severity
Beta = 0.289
eta = 0.420
B eta = -0.454 PTCI (negative appraisals)
Moderating variable Time since assault Peritraumatic dissociation
PTSD Symptomatology
Distress associated with intrusive memories: Relationship to PTCL PDEQ and PTSD: Previous research has demonstrated that posttraumatic appraisals and dissociation maintain and exacerbate PTSD through an increase in distress specifically associated with intrusive memories. Level o f distress associated with flashbacks was significantly correlated with both o f the predictor variables, PTCI (r = 0.37, p =0.05) and PDEQ (r = 0.53, p = 0.004), and also with PTSD severity (r = 0.80, p <0.0001). It may be that, as found in previous research, the increase in PTSD severity associated with negative appraisals and dissociation is mediated through an increase in distress associated with flashbacks and recollections. The increased distress associated with intrusions might be mediated by the higher ‘reliving’ shown to be associated with dissociation in this study, and impaired fear response and higher posttraumatic fear associated with negative appraisals. However, given the sample size, it was beyond the scope o f this study to investigate this using a multivariate analysis.