Posttraumatic Stress Disorder in Women with Bulimia Nervosa

Posttraumatic stress disorder (PTSD) is 3-5 times more prevalent in individuals with bulimia nervosa (BN) than those without (Dansky et al., 1997). However, the relationship between PTSD and BN–in particular, how PTSD might affect or moderate bulimic symptoms–remains largely unexplored. In a recent study, Trisha Karr and colleagues followed 119 women (20 with PTSD and BN, and 99 with BN only) for a 2 week period to investigate whether participants with comorbid PTSD + BN differed from those with BN only on the:

  1. Levels of negative affect (negative emotional state/mood) and affect variability (fluctuation between negative and positive states)
  2. Frequency of bulimic behaviours
  3. Relationship between emotional states (negative or positive affect) and bulimic behaviours

They used the ecological momentary assessment (EMA) tool to track behaviours and emotional states close to when they occurI’ve blogged about a study using EMA before (‘What’s The Point of Bingeing/Purging? And Why Can’t You Just Stop?’), but briefly,

EMA techniques provide methods by which a research participant can report on symptoms, affect, behaviour and cognitions close in time to experience, and these reports are obtained many times over the course of a study.

Participants were prompted to recording their mood and behaviour(s) at 6 semi-random times each day, over a two-week period. The authors then looked at the mood (negative and positive affect) before and after bingeing and/or purging behaviours. (See figures in this post to see what I mean.)

DEMOGRAPHIC CHARACTERISTICS

  • Mean age: 29 for PTSD + BN group, 24 for BN only
  • No differences on education level or BMI
  • PTSD + BN group was more likely to be married

Prevalence of other psychiatric disorders:

  • Mood disorders: 70% for PTSD + BN, 52% for BN only
  • Substance use disorders: 15% for PTSD + BN, 16.5% for BN only
  • Anxiety disorders: 70% for PTSD + BN, 40% for BN only (statistically significant)

In their analyses, the authors controlled for the other comorbid conditions (mood disorders, substance use, other anxiety disorders). I’ve summarized the main findings of the study below:

SUMMARY OF MAIN RESULTS

Question 1:

  • Individuals in the PTSD + BN group reported higher levels of negative affect than those with BN only.
  • The authors hypothesize that this might be due to increased “sensitivity to stimuli involving perceptions of threat, rejection, or criticism.”

Question 2:

  • Individuals in the PTSD + BN group reported higher frequencies of binge eating and purging behaviours than those in the BN only group. This is similar to other studies comparing BN women with and without a history of childhood sexual abuse, although there have been studies which found no association between trauma or abuse history and frequency of eating disorder behaviours.
  • The authors hypothesize that “Perhaps the presence of diagnosable PTSD, examined in the present study, is a more potent predictor of bulimic severity than a history of child trauma and reflects the affective dysregulation that accompanies PTSD but does not always accompany the experience of trauma or abuse.

Question 3:

  • Negative affect increased and positive affect decreased prior to binge eating for both the PTSD + BN and BN only groups. Conversely, negative affect decreased and positive affect increased after binge eating for both groups. There were no differences between groups when it came to the relationship between affect and binge eating. These findings are similar to the ones I’ve blogged about previously.
  • Interestingly, there was a difference when it came to purging. Just like for binge eating, negative affect increased and positive affect decreased prior to purging. Following purging, negative affect decreased and positive affect increased. But, negative affect increased at a faster rate before purging and decreased at a faster rate after purging for the PTSD + BN group versus the BN only group. The same pattern of a faster decrease and increase was observed for positive affect as well.
  • These findings suggest that PTSD modifies the relationship between negative and positive emotional states and purging in women with bulimia nervosa.

What do these findings, particularly the latter, mean? Well, it is hard to say. All that we know is that in this sample, women with BN and PTSD experienced more rapid increases in negative emotional states prior to purging and more rapid decreases following purging (and opposite pattern for positive states). It is interesting that this did not hold up for binge eating episodes, though.

Are these findings generalize? Again, it is hard to say. The PTSD + BN group, with only 20 participants, was 5 times smaller than the BN only group. That’s a small sample, and it is hard to say whether in a similar study with 10 times the numbers, the differences will become more significant or less.

Unfortunately, the authors did not go into detail discussing the possible implications of the findings with respect to the third question. I do not have much background in PTSD, so it is difficult for me to comment, but my first thought is that this might suggest that purging is more negative reinforcing for individuals with comorbid PTSD than those with BN only. (Negative reinforcement is the removal of an aversive stimulus.)

Taken as a whole, these data suggest that individuals with comorbid PTSD and BN experience more negative emotional states (higher daily level of negative affect) and exhibit a greater frequency of bulimic behaviours than their BN only counterparts. In addition, purging may be regulating emotions differently (or perhaps more strongly?) in individuals with comorbid PTSD + BN than BN only.

If these findings do hold up, I wonder what implications they might have for treatment of patients with comorbid PTSD and BN.

Readers, if you have experienced comorbid PTSD and BN (or any other ED), how did the PTSD affect your ED or ED recovery? Were (or are) there things that help one (PTSD or BN) at the expense of the other, or does improving PTSD symptoms concurrently improves BN symptoms, too?

Also, to plug this blog’s contributors: Shelly has written a post on her own research blog, Neurorexia, titled “I gut a feeling.” It is about bug in our brain, sorta. Go check it out!

References

Karr, T., Crosby, R., Cao, L., Engel, S., Mitchell, J., Simonich, H., & Wonderlich, S. (2013). Posttraumatic stress disorder as a moderator of the association between negative affect and bulimic symptoms: an ecological momentary assessment study Comprehensive Psychiatry, 54 (1), 61-69 DOI: 10.1016/j.comppsych.2012.05.011

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Tetyana is the creator and manager of the blog.

6 Comments

  1. Hi Tetyana – thank you so much for this. I have PTSD and I definitely think it’s complicated my eating disorder (AN type 2 binge/purge). I dissociate a lot, and often find that I dissociate when eating. I think I use bingeing as a tool to ‘split’ from having to be here, in my head and in my body. I also tend to numb out using starvation. Purging actually began in the first place not to get rid of food, but because I felt so dirty inside. Unfortunately things got tangled up and it’s very much a trigger of the past traumas to eat or have eaten, and the act of purging also seems to take me into a triggered mindset where I’m purging that feeling rather than the food. I think that the findings that the effects on feelings of those with both PTSD and BN being more rapid could have a lot to do with PTSD sufferers becoming very sensitive and highly reactive because they are continually on the lookout for danger. Apparently we do not have very good skills at self-regulation with emotions or being triggered and the panic that comes from that.
    Also, we tend to not have skills to defuse these emotions and feelings we are experiencing. I think that along with dissociating and numbing out, bingeing and vomiting is another way of ‘splitting’ from an intolerable experience.
    Sorry if this doesnt make sense, it’s 2am!
    Thank you again so much for this post – I am trying to learn more about having PTSD lately.

    • Hi Fiona,

      Thank you for your comment. And it all makes perfect sense! Fiona, you always make so much sense, and your comments are always so insightful.

      ” I think that the findings that the effects on feelings of those with both PTSD and BN being more rapid could have a lot to do with PTSD sufferers becoming very sensitive and highly reactive because they are continually on the lookout for danger. Apparently we do not have very good skills at self-regulation with emotions or being triggered and the panic that comes from that.
      Also, we tend to not have skills to defuse these emotions and feelings we are experiencing. I think that along with dissociating and numbing out, bingeing and vomiting is another way of ‘splitting’ from an intolerable experience.”

      I think the above is particularly illuminating and I can definitely see why that would be the case. Like I said in the post, I do wonder if that would contribute to making recovery (or stopping purging) harder, because it seems to be (and I wonder if that’s the case), more powerful in regulating negative affect? (Faster =/ more powerful, but I don’t know.)

      I don’t have PTSD, but I definitely get you on the “purging feelings” and feeling dirty. I sometimes have a desire to purge just when I’m filled with all these unpleasant emotions and feelings. That’s why I actually like the word purging as opposed to vomiting or throwing-up. It sees more apt.

      I’ll hopefully be blogging more about this topic, as it does seem like a lot of people are interested in it, and it is an important one to explore.

      Thanks again,
      Tetyana

  2. ‘PTSD + BN group was more likely to be married’

    Hmmm. Interesting.

    Like Fiona said, I think my dissociation (related to PTSD) sometimes makes it notably easier to engage in behaviors. Feeling like ‘I’m not really here; this isn’t really me’ makes it a hell of a lot easier (in the moment) for me to justify a binge/restricting/etc.

    • Yeah, I thought that was interesting too, but then I realized they were, on average, 4-5 years older. So you know, between 24-28/29, that’s a big difference when it comes to marriage, I feel.

        • I would also say that I’ve often felt “I’m not really here/this isn’t really happening” as well. I wouldn’t say that for me it was dissociating, because I still was aware that I was me, in a sense, but it was a very kind of, apathetic and removed, state. Like I’m a few inches off the ground or like there’s a glass wall surrounding me. It definitely facilitated bingeing and purging. I was too zoned out to be able to actively stop myself before it was too late. I think it happened when I was so anxious that my brain immediately went to symptoms, without even processing the emotions.

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