Evaluación de las propuestas de solución

□ Hypothesis four is partially supported as higher trait dissociation as measured by the DES does not lead to a greater incidence o f intrusive

memories. Participants with a greater score on the DBS do not have a greater number of intrusions over all. However, a higher score on the pathological form o f trait-dissociation (the DES-T ) does not lead to a greater incidence of intrusive memories.

This result replicates the finding in the first study, and Holmes (2000) and the postulated reasons for this result were discussed on pages 67-68.

The finding in the grounding study with a random sample, and Holmes’ finding with a sample of highly dissociative students, is also apparent in this sample who are highly hypnotisable, which suggests that the finding may be generalisable to other

populations. A replication of a previous result also suggests that the finding can be considered more reliable as is not as likely to be attributable to type 2 error.

Mood and distress

□ Hypothesis five a) was not supported as during the hypnosis phase of the film, participants did not appear to experience more peri-traumatic emotional numbing than when they perform no task during the film as measured by post- film negative mood ratings, though there was a trend in the predicted

□ Hypothesis five b) was partially supported as depression is reported to be experienced more in the control condition than the hypnosis condition, but fear is not.

□ Hypothesis six was supported. During the control film, participants obtained higher distress ratings than during the hypnotic induction film.

The straightforward interpretation o f these results is that a composite score of negative mood change is not related to dissociation as in the previous study. Alternatively, the null finding of hypothesis 5a may represent a problem with statistical power as the mean negative mood score in the hypnosis condition was considerably lower than that in the control condition, though this did not obtain statistical significance. If this is the case, it may indicate that the effect size we should be looking is smaller than anticipated. It was difficult to predict a potential effect size in this study as these mood measures have not been used in a study before.

Using a larger sample size would help to reveal a smaller effect size if present and if it did not, we would be able to state more conclusively that these moods do not appear to be a central part of the dissociative experience we are inducing during trauma. We must be aware though that it is possible that it is only in real-life traumatic situations that such an effect would be seen to occur. This would particularly apply to the lack of a significant difference in fear across the two conditions, which we would expect in an actual trauma. However, this may also reflect a lack of power in this study as the trend was in the predicted direction.

Overall, these findings suggest that emotional numbing for these particular feelings (depression and distress) occur at the time of the traumatic event. This would mean

that emotional numbing should not merely be construed as a secondary avoidance strategy as in DSM IV. Other researchers have argued that the three factor model proposed in DSM IV does not fit the available data and have proposed that emotional numbing should be placed on a separate cluster all on its own (King, Leskin, King & Weathers 1998). This study would tend to support their proposal. These findings also contradict Horowitzs’(1986) information processing theory which suggests that emotional numbing occurs in response to the aversive emotions which are associated with re-experiencing.

Participants were not explicitly asked to try to dampen their emotions which suggests that, this either naturally occurs while experiencing high levels of dissociation, or some particular factor in our induction created this effect. We asked the participants to imagine themselves outside their body and see themselves as if looking at another person, which as stated, is an aspect of depersonalisation. This has been postulated to appear in response to high emotional arousal. It is also possible that the numbing appeared in response to our suggestion that the world seemed strange and unreal, though there is no theory to account for this.

This finding also suggests that Litz’s (1992, 1997) proposal linking emotional numbing to hyperarousal may be rather overstated. It seems likely that participants were suffering at least some hyperarousal (this could be ascertained by taking physiological measures in future studies), but this state was not prolonged, and the effect must have occurred within the brief time-period of the video. The link that has been found between hyperarousal and emotional numbing may also be explained by hyperarousal being a necessary precursor to emotional numbing occurring. There would be no need to dampen down arousal if it were not already at an uncomfortable level. Loading on the same factor may simply mean that it is only those people who

are likely to experience hyperarousal symptoms who will also exhibit emotional numbing. There does not necessarily need to be a prolonged period of hyperarousal to explain the numbing effect, though it is probable that prolonged hyperarousal would reinforce the numbing effect.

In conclusion, this study demonstrated that both depression and distress were

significantly lower when participants were reporting higher levels of dissociation. No such effect was found in the grounding study in which participants failed to record high levels of dissociation.