11.1. What is the prognosis of eating disorders?

Anorexia nervosa

There are contradictory data on the prognosis of AN despite its long historical trajectory, motivated by several factors: follow-up studies with great temporal variability, different results depending on when these studies are performed, lack of randomised intervention studies with sufficient outcome assessment, etc.

Acknowledging the previous limitations, results derived from the review of the main studies and SRSE of AN prognosis indicate that: mean gross mortality rate is 5% with a high standard deviation (5.7) and a 0 to 22 interval^{388, 389.} Gross mortality rates are generally superior to those of the general population and increase significantly with the duration of follow-up. In contrast to this data, it seems that the overall outcome in survivors improves with duration of follow-up (with the resulting therapeutic implications).

50% of AN cases resolve in complete remission^390-392. Partial remission is observed in 20%-30% of AN cases^{388, 391}. Between 10% and 20% of cases result in chronicity^{389, 391, 393}.

Bulimia nervosa

The natural course of BN at 5 years in patients who live in a community is as follows: each year, 33% result in remission and 33% in relapse. This information indicates a relatively poor prognosis for non-treated individuals⁷⁴.

In 6-year follow-up studies of treated individuals, 60% were determined to have good prognosis, 30% were considered partially recovered and 10% were determined to have poor prognosis³⁹⁴.

Risk factors of diagnosis modification (AN to BN or vice versa)

There is a lack of prospective studies focused on the evolution of AN based on the survival analysis model. However, the following risk factors for diagnosis modification from AN to BN or from BN to AN are: low self-sufficiency or autonomy, high paternal criticism, alcohol abuse/dependency, low sensation seeking level³⁹⁵.

Binge-Eating Disorder

In follow-up studies at 5 years, 10% of cases diagnosed with BED maintained the diagnosis, 18% to 20% presented partial remission and 70% were determined to have good prognosis. The presence of binge-eating predicts weight gain. The prevalence of obesity was duplicated in the group of patients who presented disorder maintenance by the end of the study ⁷⁴.

11.2. Are there prognostic factors in eating disorders?

Anorexia nervosa

1. Good prognostic factors: histrionic personality traits³⁸⁸, onset in adolescence^{393, 396}. In the latter case, it would not exactly be a good prognostic factor but rather a better prognostic factor than onset of AN in adulthood.
2. Poor prognostic factors: comorbidity with other psychiatric disorders (mood disorders, anxiety disorders, substance abuse), presence of self-induced vomiting, binge-eating or laxative abuse, obsessive-compulsive personality traits, social adjustment and disease duration ^{388, 395, 397}.

Bulimia nervosa

1. Good prognostic factors: the earlier treatment has been initiated, the better prognosis. This factor is deemed to be the best indicator of good prognosis, even more than the type or duration of given treatment³⁹⁸; it also correlates with good prognosis at the beginning of the disease in adolescence when compared to onset in adulthood³⁹⁹.
2. Poor prognostic factors: history of substance abuse or laxative abuse predict suicide attempts⁴⁰⁰; comorbidity with OCD is associated with longer disease duration⁴⁰¹; history of eating conflicts and/or refusal at early stages of childhood⁴⁰²; poor psychosocial functioning and greater disturbance of body image are the factors that most influence BN relapse

Binge-Eating Disorder

1. Poor prognostic factors: the presence of binge-eating episodes predicts weight gain. The prevalence of obesity was duplicated in the group of patients who sustained BED by the end of the study⁷⁴. The presence of Cluster B personality traits predicts greater frequency of binge-eating episodes.⁴⁰⁴.