Symptom fluctuation and diagnostic crossover are common in eating disorder patients. A study by Eddy et al. (2008) – who followed patients over an average of 7 years – showed that crossover between subtypes and full-syndrome diagnoses is very common : of those initially diagnosed with anorexia nervosa, almost 73% crossed over to another diagnosis (between symptoms and to bulimia nervosa). More specifically, roughly 50% experienced fluctuation between subtypes (restricting, AN-R, and binge/purge type, AN-BP) and roughly 35% crossed over to bulimia nervosa (a subset experienced both). Of those initially diagnosed with bulimia, roughly 14% crossed over to AN-BP and of those, 3.91% crossed over to AN-R.
This finding (though, well-known to ED specialists and even more well-known to patients) has important implications for treatment. For example, CBT and anti-depressants seem to have positive results in bulimic patients, but not so much in anorexics. What then, about those that crossover from AN-R/AN-BP to BN? Would they, too, benefit from these interventions?
In order to answer those questions, it would be helpful to know who whether we can actually predict who will crossover. In order words, are there any characteristic traits that correlate with a crossover in diagnosis? Tozzi and colleagues investigated this question in multi-site study that was published in 2005.
SUMMARY OF FINDINGS:
- 36% of those with initial diagnosis of AN-R developed bulimia nervosa, 91% crossed over in the first 5 years of the illness
- 27% of those with bulimia developed AN-BP, 77% crossover over during the first five years
CORRELATES OF CROSSOVER:
From anorexia nervosa to bulimia nervosa
- low self-directedness
- high parental criticism
- trait anxiety
- substance abuse
From bulimia nervosa to anorexia nervosa
- low self-directedness
- low novelty seeking
- high harm avoidance
- alcohol abuse/dependence
- avoidant personality disorder
Bold points are strongly correlated with the crossover. This is a graphical representation of the time-to-crossover (based on self-reports):
The authors used various questionnaires to evaluate these traits. To evaluate temperament and character they used the Temperament and Character Inventory (TCI). I’m not a psychologist, so I’m not particularly familiar with these questionnaires and what they assess, but I did find a nice description on this site, here:
The TCI is a set of tests designed to identify the intensity of and relationships between the seven basic personality dimensions of Temperament and Character, which interact to create the unique personality of an individual.
Temperament refers to the automatic emotional responses to experience and is moderately heritable (i.e. genetic, biological) and stable throughout life. The four measured Temperament dimensions are Novelty Seeking (NS), Harm Avoidance (HA), Reward Dependence (RD), and Persistence (PS).
Character refers to self-concepts and individual differences in goals and values, which influence voluntary choices, intentions, and the meaning and salience of what is experienced in life. Differences in character are moderately influenced by socio-cultural learning and mature in progressive steps throughout life. Character takes into account the psychology of the development of personality. The three measured Character dimensions are Self-Directedness (SD), Cooperativeness (CO), and Self-Transcendence (ST).
Results from Tozzi et al suggest that self-directedness is common predictor of crossover for AN –> BN and BN –> AN. Indeed, from the characteristics evaluated, only self-directedness is common to both crossovers. But what exactly is it, and what does this finding suggest?
From the site above:
Self-Directedness quantifies the extent to which an individual is responsible, reliable, resourceful, goal-oriented, and self-confident. The most advantageous summary feature of self-directed individuals is that they are realistic and effective, i.e., they are able to adapt their behavior in accord with individually chosen, voluntary goals based on a realistic assessment of facts. Individuals low in Self-Directedness are blaming, helpless, irresponsible, unreliable, reactive, and unable to define, set and pursue meaningful internal goals. Such poor resourcefulness and unrealistic behavior are often disadvantageous to the individual.
Tozzi et al hypothesize that “individuals with low self-directedness, independent of diagnosis, may be characterized by an inability to regulate behaviors and affect adequately.” This may then lead to alternation between restraint in restricting anorexia and impulsivity in binge-purge type anorexia and bulimia nervosa.
High-parental criticism was associated with crossover from anorexia to bulimia:
This finding is noteworthy given early observations of family environment across eating disorder subtypes, suggesting that families of individuals with bulimia tended to exhibit greater conflict and disorganization and less cohesion than families of those with anorexia nervosa (56), that mothers of individuals with bulimia nervosa were reported to be more domineering and have higher expectations of their daughters than were control individuals (57), and that women with bulimia nervosa reported maternal deficits in nurturance and empathy (58).
Our findings also corroborate those of Strober et al. (4), who found low levels of parental empathy and affection to be significant predictors of the onset of binge eating in women with anorexia nervosa. These observations are particularly noteworthy, given the finding in expressed emotion research that maternal critical comments are strongly predictive of treatment outcome for adolescents with eating disorders (59).
I am kind of fascinated by this finding. In part because I keep reflecting back on my eating disorder trajectory and family life. I suppose I’m surprised at the fact that it seems to be a very important predictor of crossover, specifically from AN to BN. I guess I didn’t think it would be so important? Readers, what do you think?
Predictors of crossover from BN to AN (particularly low impulsivity and novelty-seeking) are to be expected. Anxiety was not found to correlate with crossover in this study, though previous studies have suggested that it is important in predicting crossover from AN to BN. Tozzi et al suggest this discrepancy may be due to the use of different methods and tests to evaluating anxiety.
Some limitations of the study to keep in mind, I think 2 and 5 are particularly important:
- (1) inability to examine all possible diagnostic crossovers;
- (2) 57% of those with AN and 38% of those with BN were evaluated before the fifth year of their illness and thus might not have reached their “steady state”, as Tozzi et al. write;
- (3) limited/no details about changes of severity in illness (partial/full recovery between AN and BN? – I had partial remission from AN, prior to onset of BN, which led to AN-BP and then back to AN);
- (4) no data on childhood psychiatric disorders and sexual abuse (previously shown to be important predictors);
- (5) “onset of diagnoses and determination of crossover were based on retrospective reports and may be subject to recall bias”
The authors suggest that given the fact that “low self-directedness has been associated with a negative outcome.. [and] high self-directedness predicts rapid and sustained response to CBT in BN patients,” treatment approaches would be wise to utilize methods of increasing the levels of self-directendess in patients.
I definitely think this is true – recovery and remission, for me, is always associated with generally behaving much more responsibly and reliably. I’m generally a goal-oriented individual, but that definitely has fallen to the way-side in the past, when bulimic symptoms were particularly dominant. I think things have never gotten that bad precisely because when my ED starts interfering significantly with my goals, directly or indirectly, it motivates me to really focus on reducing symptoms, which then gives me more time and mental energy to be more involved and this further helps recovery.
Readers, I’d love to hear any thoughts you have on these findings? Do you think they make sense and are they representative of your experiences and observations?
Side note: I’m sorry for the delay between my previous post and this one. Social life sometimes get in the way, which is, frankly, pretty awesome. I’ll try to make another post tonight or tomorrow.
Tozzi F, Thornton LM, Klump KL, Fichter MM, Halmi KA, Kaplan AS, Strober M, Woodside DB, Crow S, Mitchell J, Rotondo A, Mauri M, Cassano G, Keel P, Plotnicov KH, Pollice C, Lilenfeld LR, Berrettini WH, Bulik CM, & Kaye WH (2005). Symptom fluctuation in eating disorders: correlates of diagnostic crossover. The American Journal of Psychiatry, 162 (4), 732-40 PMID: 15800146