Research suggests that suppressing unwanted thoughts is not possible, leads to a subsequent increase in frequency of the suppressed thoughts, and results in higher levels of distress. Because thought suppression may have negative effects, an alternative, acceptance-based approach has been proposed. The current paper reports the outcomes of two studies. Study I examined the relationships between two naturally occurring strategies of thought management (thought suppression and acceptance), symptoms of psychopathology, and experiences with personally relevant intrusive thoughts. Results showed that those who naturally suppress personally relevant intrusive thoughts have more, are more distressed by, and have a greater “urge to do something” about the thoughts, while those who are naturally more accepting of their intrusive thoughts are less obsessional, have lower levels of depression, and are less anxious. Study II compared three groups (thought suppression, acceptance, and monitor-only groups) on the frequency and distress associated with experiencing personally relevant intrusive thoughts. Results revealed that those instructed to suppress their personal intrusive thoughts were unable to do so and experienced an increased level of distress after suppression, whereas those instructed to use an acceptance-based strategy experienced a decrease in discomfort level (but not thought frequency) after having used such a strategy. These data offer initial evidence that acceptance may be a useful alternative to the suppression of personally relevant intrusive thoughts.
Experiential avoidance is a process in which an individual attempts to change the form or frequency of private events (e.g., emotions, thoughts, memories) that he/she is unwilling to experience (Hayes, Wilson, Gifford, Follette, & Strosahl, 1996). This is usually done by avoiding or modifying either the event itself (e.g., thought, emotion) or certain contexts that occasion the event. Early research on thought suppression, a type of experiential avoidance, demonstrated that emotionally neutral thoughts occurred more frequently when participants had been asked to suppress the thought compared to when they had been asked to express the thought (Wegner, Schneider, Carter, & White, 1987). In addition to this “immediate enhancement effect,” a “rebound effect” was discovered, in which those who were initially asked to suppress a thought experienced that thought more frequently during a subsequent expression period, as compared to those who first expressed and then suppressed. Combined, these findings suggest that as a self-control strategy, thought suppression has paradoxical effects, in that it produces the very thought to be avoided.
Since the Wegner et al. (1987) study, numerous researchers have continued to examine thought suppression. Many have replicated the aforementioned paradoxical effects using a variety of neutral target thoughts (e.g., Bowers & Woody, 1996; Clark, Ball, & Pape, 1991; Clark, Winton, & Thynn, 1993), and the effects have been found to continue over longer periods of time (Muris & Merckelbach, 1991). However, not all subsequent studies using neutral target thoughts have provided support for these paradoxical effects (e.g., Merckelbach, Muris, van den Hout, & de Jong, 1991; Muris, Merckelbach, van de Hout, & de Jong, 1992).
Other researchers have studied the effects of suppressing personally relevant intrusive thoughts (as opposed to neutral thoughts). Like the research on neutral thoughts, some studies have found the immediate enhancement effect when personally relevant intrusive thoughts were suppressed (e.g., Salkovskis & Campbell, 1994; Trinder & Salkovskis, 1994), whereas others have not (e.g., Janeck & Calamari, 1999; Kelly & Kahn, 1994; Purdon & Clark, 2001). However, none of the studies have found evidence of the rebound effect (Janeck & Calamari, 1999; Kelly & Kahn, 1994; Purdon & Clark, 2001; Salkovskis & Campbell, 1994; Trinder & Salkovskis, 1994).
Although it remains unclear whether thought suppression increases the frequency of personally relevant intrusive thoughts, some (e.g., Purdon & Clark, 2001) have argued that the discomfort associated with thought suppression should be the target of inquiry rather than the frequency of thoughts. Evidence for this comes from studies suggesting that persons who suppress personally relevant intrusive thoughts are more distressed and have higher levels of discomfort after doing so (Purdon & Clark, 2001; Trinder & Salkovskis, 1994).
5.1. Experimental manipulation
To assess the effectiveness of the experimental manipulation, a one-way ANCOVA was conducted to determine whether the groups differed on effort to suppress target thoughts (thought suppression effort rating) during the experimental period, controlling for the effort to suppress during the baseline period. Results showed a significant group difference on effort to suppress during the experimental period, F(2,99)=5.26F(2,99)=5.26, p<.01p<.01. Subsequent analyses showed that the thought suppression group (M=4.30M=4.30, SD=3.14SD=3.14) exerted significantly more suppression effort than the monitor-only (M=2.73M=2.73, SD=2.13SD=2.13), F(1,63)=7.34F(1,63)=7.34, p<.01p<.01, d=.59d=.59, or acceptance group (M=3.24M=3.24, SD=2.81SD=2.81), F(1,67)=7.33F(1,67)=7.33, p<.01p<.01, d=.36d=.36.
