Anorexia has become a very common disorder in the last fifty years, especially due to the imposition of the female beauty canon, characterized by extreme thinness in women.

As this eating disorder increases, there have been more and more cases where the patient not only manifests this disorder, but also suffers from some kind of added psychiatric problem.

Next we will see the main comorbidities of anorexia , together with the treatment routes that are usually used for this type of combined disorder.

Anorexia comorbidities

Anorexia nervosa is an eating behavior disorder. In this disorder, the patient has a body mass index (BMI) that is significantly lower than that expected for a person of the same height and age, usually less than 85% of the expected weight. This low body size is due to an intense fear of gaining weight, which is accompanied by food-rejection behaviors .

Comorbidity is understood to be the presence of two or more psychiatric disorders or medical conditions, not necessarily related, occurring in the same patient. Knowing the comorbidity of two disorders, in this case anorexia and another one, whether it is this anxiety disorder, mood disorder or personality disorder, allows us to explain the appearance of both in the same patient, as well as to provide the appropriate information to professionals and proceed to carry out assessments and therapeutic decisions.

1. Bipolar disorder

Comorbidity between eating disorders and bipolar disorder has been investigated. The reason why psychiatric research is increasingly focusing on this line of study is that eating disorders are more frequent in the bipolar population, which requires designing specific treatment for patients with both diagnoses .

It is important to adjust treatment so that it does not make the mistake of, for example, trying to improve the prognosis of a case of bipolar disorder, harming the course of ACT as a side effect.

The emotional lability of anorexic patients may be mistaken for symptoms of bipolar disorder. It should be noted that the main problem in patients who meet criteria for diagnosis with both disorders is the patient’s concern about one of the side effects of bipolar disorder medication, usually lithium and atypical antipsychotics, which can cause weight gain.

This comorbidity is especially striking in the case of patients who are in a state of malnutrition and the depressive episode of bipolar disorder. The symptoms of depression can be confused with the lack of energy and lack of libido of anorexic patients who have just started treatment.

2. Depression

One of the main problems in treating depression in patients with eating disorders, and especially with cases of anorexia nervosa, is making an accurate diagnosis. Since patients with anorexia often present with malnutrition and lack of energy , it may be the case that depression is camouflaged among the symptoms of starvation. Many patients will recognise that their mood is not normal and describe it as ‘depressed’, but this does not necessarily have to be the case.

That is why it is necessary to follow rigorously how the patient evolves once she is under treatment to increase weight and have normal levels of nutrients in her blood. Malnutrition and depression share very striking symptoms such as loss of libido and sleep disturbances, which is why, once the person is no longer malnourished, if these symptoms are still observed, it is possible to make the diagnosis of depression.

Once the person with anorexia nervosa has been identified with a diagnosis of depression, psychotherapeutic and pharmacological treatment is usually undertaken. In these cases, any antidepressant is acceptable, with the exception of bupropion . The reason for this is that it may cause epileptic seizures in those who binge and later purge. While these symptoms are typical of bulimia nervosa, it is worth noting that progression from one ACT to another is relatively common.

The dosage of antidepressants in patients with anorexia nervosa is something that should be monitored, since, as they are not in normal weight, there is a risk that, when prescribing a normal dose, a case of overdosage is occurring . In the case of fluoxetine, citalopram and paroxetine, it is usually started at 20 mg/day, while venlafaxine at 75 mg/day and sertraline at 100 mg/day.

Whatever type of antidepressant is prescribed, professionals make sure that the patient understands that, if he or she does not gain weight, the benefit of antidepressants will be limited. In people who have reached a healthy weight, taking these drugs is expected to result in about a 25% improvement in mood. However, to ensure that this is not a false positive for depression, professionals make sure that 6 weeks of improved eating habits pass before pharmacologically addressing the depression.

It is important not to forget psychological therapy, especially cognitive-behavioral therapies , given that most of the treatments for ATD, especially anorexia and bulimia, involve working on the cognitive component behind the body distortions present in these disorders. However, it is necessary to highlight that very underweight patients are too malnourished to benefit from this type of therapy in the short term.

3. Obsessive-compulsive disorder (OCD)

There are two main factors to consider regarding obsessive-compulsive disorder (OCD) combined with ACT.

First, food-related rituals , which can hinder the diagnosis and may be seen as more related to anorexia than to OCD itself. In addition, you may engage in excessive exercise or obsessive behaviors such as repetitive weighing.

The second factor is the common personality type in patients with both disorders, with perfectionist traits , aspects of the personality that persist even after normopause has been reached. It’s worth noting that having rigid and persistent personality traits that persist beyond the point of therapy is not a clear indication that you’re dealing with a person with OCD.

Drug treatment is usually started with antidepressants such as fluoxetine, paroxetine or citalopram. An additional strategy is to incorporate small doses of antipsychotics, as some experts believe this contributes to a greater and faster therapeutic response than if only antidepressants are administered.

4. Panic disorder

The symptoms of panic disorder, with or without agoraphobia, are problematic in both an ATD patient and any other patient.

The most common treatment of choice is a combination of antidepressant s along with the already traditional cognitive therapy. Once treatment has been started, the first symptoms of improvement are seen after six weeks.

5. Specific phobias

Specific phobias are not common in patients with ACT, apart from the fears related to the disorder itself, such as the phobia of weight gain or of particular foods, especially those rich in fat and carbohydrates . These types of fears are treated along with anorexia, since they are symptoms of it. It does not make sense to treat the patient’s body distortion or aversion to dishes such as pizza or ice cream without considering her nutritional status or working on anorexia as a whole.

It is for this reason that it is considered that, leaving aside body and food phobias, specific phobias are equally common in the anorexic population as in the general population.

6. Post-Traumatic Stress Disorder (PTSD)

PTSD has been seen as a highly comorbid anxiety disorder with altered eating behavior. It has been shown that, the more severe the ATD, the more likely it is that PTSD will occur and be more severe , with a link between both psychiatric conditions. In developed countries, where people have been living in peace for decades, most cases of PTSD are associated with physical and sexual abuse. It has been found that nearly 50% of people with anorexia nervosa would meet the criteria for a diagnosis of PTSD, with the cause being mostly childhood abuse.

However, there is much controversy between being a victim of traumatic events and their effect on other comorbid diagnoses. Individuals who have been sexually abused over a long period of time tend to have mood swings, unstable sexual/love relationships, and self-conscious behavior, all of which are symptoms associated with borderline personality disorder (BPD). This is where the possibility of a triple comorbidity arises: ACT, PTSD, and BPD.

The pharmacological pathway is complex for this type of comorbidity. It is common for the patient to present severe mood changes, high intensity and phobic behaviour , which would suggest the use of an antidepressant and benzodiazepine. The problem is that this has been found not to be a good option because, although the patient’s anxiety will be reduced, there is a risk of overdosing, especially if the patient has obtained the drugs from multiple professionals. This can lead to adverse effects such as seizures.

In this type of case, it is necessary to explain to the patient that it is difficult to treat the anxiety completely by means of pharmacology, which allows a symptomatic but not total reduction of PTSD. It should be noted that some authors consider more appropriate the use of atypical antipsychotics at low doses instead of benzodiazepines, since patients do not tend to escalate their dose.

7. Substance abuse

Substance abuse is a difficult area to study in terms of its co-morbidity with other disorders, since symptoms can be intermingled. It is estimated that about 17% of people with anorexia manifest alcohol abuse or dependence throughout their lives . It should be noted that, although there is enough data regarding alcoholism and ATDs, the rates of abuse of drugs, especially benzodiazepines, in the anorexic population are not so clear.

Cases of anorexia combined with substance abuse are particularly sensitive. When one of these is detected, it becomes necessary, before applying any pharmacological treatment, to admit them to rehabilitation to try to overcome their addiction. Alcohol use in anorexics with a very low BMI complicates any drug treatment.

Bibliographic references:

  • Godoy-Sánchez, L. E.; Albrecht-Roman, W. R. and Mesquita-Ramírez, M. N. (2019) Psychiatric comorbidities of anorexia and bulimia nervosa in pediatrics. Rev. Nac. 11(1), pp.17-26. ISSN 2072-8174. http://dx.doi.org/10.18004/rdn2019.0011.01.017-026
  • Woodside, B.D. & Staab, R. (2006) Management of Psychiatric Comorbidity in Anorexia Nervosa and Bulimia Nervosa CNS Drugs 20: 655. https://doi.org/10.2165/00023210-200620080-00004