The opportunity to avoid pain may paradoxically increase fear

Fear-avoidance models propose that pain-related fear may spur avoidance behaviour leading to chronic pain disability. Pain-related fear elicits avoidance behaviour, which is typically aimed at reducing fear. We hypothesized that engaging in avoidance may (paradoxically) increase rather than decrease pain-related fear (i.e. bidirectionality hypothesis). In a between-subject design, participants (N=64) were randomly assigned to the avoidance group or the control group. Avoidance group participants were led to believe they could avoid full exposure to a painful heat stimulus by pressing the stop-button, while control group participants believed they were exposed to the full painful heat stimulus at all times. In reality and unknown to the participants, the intensity and duration of the heat stimulus was independent of the avoidance response, and was identical in both groups. During the test, the avoidance response (i.e. pressing the stop-button) was no longer available. As expected, pain-related fear levels were higher after avoiding the painful heat stimulus. Interestingly, in the avoidance group, pain-related fear increased after receiving instructions that avoidance would be possible, even before actually engaging in avoidance behaviour. In the control group, no significant change was observed in pain-related fear throughout the experiment. The eyeblink startle measures did not corroborate this data pattern.

PERSPECTIVE: These observations provide partial support for the bidirectionality hypothesis between avoidance behaviour and fear. These findings may have clinical implications and suggest that allowing avoidance behaviours during treatment may thwart fear reduction.