I defended my MSc on Tuesday and I’m not going to lie: I was pretty symptomatic with bulimia in the days prior to my defence. As I explained to my boyfriend: the anxiety-reducing effects of purging are so powerful, and the compulsion to binge and purge (when I’m stressed/anxious/”not okay”) is so strong that it is much easier to do it, get it over with, and continue working (in a much calmer state).
I’ve mentioned before, for me, purging is very anxiety-reducing and in some ways, almost a positive experience. It is so tightly coupled with bingeing that it is hard to separate the two, but the anxiety-reducing effects are strongest when I binge and purge, non-existent when I binge, and weak when I purge a normal meal (which is exceptionally rare/almost never.)
It turns out, of course, that I’m not alone.
Negative emotional states and stressors have long been associated with bingeing and purging (b/ping). In particular, they were thought to precede (or occur before) b/ping events. But of course, anecdotal evidence from clinical practice, while important, is not scientific.
Several small studies have been done to examine the relationship between emotional states/events and b/ping behaviours. In 1982, Johnson and Larson had 15 BN women and 24 control women keep a daily diary for a week (with recordings 7 times a day). They found that negative moods preceded b/ping events and that women with BN had more variable mood states and were generally less happy (more dysphoric).
Since then, several other studies have attempted to answer this question. In general, they found that bingeing/purging is preceded by low mood and/or high stress levels. But the studies are not without problems. For most, the sample sizes are quite small and many relied on retrospective reports (subject to memory biases).
A few years ago, Joshua Smyth and colleagues published a study that tracked mood, stress, and bulimia nervosa symptoms in 131 women with BN over a 2 week period. In order to avoid retrospective reports, they used something called the ecological momentary assessment or EMA. Essentially, it allows researchers to collect data in “real-time.” The participants had to report on mood, stress, and BN behaviours at six semi-random time points during the day in response to a signal.
Smyth wanted to compare (1) the mood and stress reports on days with bingeing/purging events and days without b/ping events and (2) the mood and stress trajectories prior to and following the first b/ping event of the day.
Over the two weeks, the women reported an average of 8.5 binge eating episodes and 11.5 purging episodes. Compliance with the EMA was also quite good (86%).
SUMMARY OF MAIN FINDINGS
Non-B/P days vs. B/P days
Unsurprisingly, Smyth et al. found that the women experienced significantly higher levels of negative/unpleasurable mood states, anger, hostility, and stress and less positive moods on days when they engaged in bingeing and purging. This is not surprising as it supports previous research findings dating back to 1982.
Before B/P vs. After B/P
What’s more interesting is to see how mood states and stress levels changed before and after bingeing/purging. Smyth et al. were interested in the changed before and after the first bingeing/purging event.
Here’s a summary figure of what they found:
As you can see, there was a rapid drop in negative affect (aversive mood states), anger/hostility, and stress levels following bingeing and/or purging and an increase in positive affect (positive mood states).
What’s more, the rate of “recovery” of these mood states was significantly more rapid following the bingeing/purging event than their “decay” prior to the event. This is interesting and I must admit, kind of cool to see in print, because it wholeheartedly supports my personal experiences.
Smyth et al.’s use of the EMA and the large sample size add stronger support to previous, small and often retrospective, studies.
The EMA provides a unique opportunity to examine the potentially (affectively) reinforcing nature of engaging in bingeing or vomiting behaviors for women with BN.
On a more global level, BN-events are quite negative. That is, BN-events commonly occur on days with significantly “worse” moods and, even at the moment when mood is best on BN-event days, moods are more negative than on days when no BN-events occur.
In sharp contrast, however, the proximal (or local) mood trajectories around a BN-event appear to hold markedly different reinforcing properties (at least for women with BN; cf. Wegner et al., 2002). Mood significantly worsened (less PA, more NA and AH) leading up to BN-events but improved (significantly more rapidly) following the event.
This suggests that, local to the event (i.e., within a few hours), bingeing or purging behaviors are strongly negatively reinforcing as they allow escape/ avoidance of a strongly negative affective state. This (local) reinforcing pattern provides support for the persistence (and resistance to change) of binge and purge behaviors, yet is also consistent with the view that such behaviors are not effective overall (global) coping efforts.
YES! THIS! I couldn’t have said it better myself.
Negative reinforcement sounds like a contradictory thing, doesn’t it? But what it means is that something is reinforcing because it removes a negative condition. In this case, bingeing and purging is reinforcing because it removes the negative mood/state.
Generally, my mood is much lower on days I binge and purge, particularly if I do it more than once. But, my anxiety/stress levels drop sharply following the first binge/purge episode. The drop in negative mood states decreases with each successive b/p (for me) and I think that’s for a few reasons. One, as I’ve blogged about before, there are powerful physiological processes that predispose one to “marathon/chain b/ping” (namely, a drop in blood sugars to fasting levels following purging), and two, I get progressively more annoyed with myself and physically tired.
In any case, I’m interested to hear what you think about these data and whether they reflect your personal experiences or not! Let me know in the comments.
Smyth, J., Wonderlich, S., Heron, K., Sliwinski, M., Crosby, R., Mitchell, J., & Engel, S. (2007). Daily and momentary mood and stress are associated with binge eating and vomiting in bulimia nervosa patients in the natural environment. Journal of Consulting and Clinical Psychology, 75 (4), 629-638 DOI: 10.1037/0022-006X.75.4.629