The role of medications in the treatment of eating disorders

By Dr Mimi Israel,
psychiatre, Hospital Douglas

Eating disorders are complex conditions with serious physical and psychological consequences.

Their onset in the peak of development heightens the risk of permanent and potentially life threatening damage to the body, as well as impairing the affected persons capacity to function at work, at school and in social situations. Eating disorders result in loss of productivity, loss of potential and a great deal of suffering for those affected and their families. It is therefore not surprising to discover that almost everv psychiatric medication has been tried in the hope of rinding a way to either treat eating disorders or in the least to minimize their consequences.

When examining the role of medications in the treatment of eating disorders, it is important to separate anorexia nervosa from bulimia nervosa and binge eating disorder, as they appear to respond differently to pharmacological treatment. In addition, one must consider the fact that eating disorders are frequently associated with other potentially treatable conditions such as depressive disorders, anxiety disorders, obsessive-compulsive disorder, and drug and alcohol abuse and dependence. Finally, one must distinguish medications used to treat eating disorders from medications used to treat the complications of eating disorders.

Some background information about antidepressants

Antidepressants are drugs used to treat depression. Most are also effective in the treatment of anxiety disorders, obsessive-compulsive disorder, bulimia nervosa and binge eating disorder.

All currently available antidepressants act by increasing the levels of certain neurotransmitters in the brain. Neurotransmitters are chemical messengers that form part of a system that transmits information from one brain cell to another. The most studied neurotransmitter in the field of eating disorders is serotonin, a neurotransmitter believed to play a role in appetite regulation, mood regulation and impulse control. Most antidepressants currently on the market directly or indirectly increase the neurotransmission of serotonin. The exact role of serotonin in the development or maintenance of eating disorders is not understood. However, accumulating evidence supports the view that eating disorders are the result of an interaction between biological, psychological and social factors rather than having one single cause.

Presently, the most frequently prescribed antidepressants are the selective serotonin reuptake inhibitors (SSRIs) which include Fluoxetine (Prozac), Sertraline (Zoloft), Paroxetine (Paxil), Citalopam (Celexa) and Fluvoxamine (Luvox). Other antidepressants currently in use include Venlafaxine (Effexor), Nefazodone (Serzone), Bupropion (Wellbutrin), and Mirtazepine (Remeron). Bupropion is also marketed as Zyban and used to help people stop smoking.

Medications and Anorexia:

For the moment the best available treatment for anorexia is "Food". Although antidepressants are not found to be useful in treating people with anorexia while they are still underweight, some studies have found that antidepressants could play a role in preventing relapse if started once healthy bodyweight is reached. Antidepressants may also be helpful, if a person with anorexia also suffers from clinically significant depression, anxiety or obsessive-compulsive disorder. Usually, the antidepressant will alleviate the associated condition (e.g. depression) without necessarily treating the anorexia.

So far, only SSRIs have been studied in anorexia, but other antidepressants may also be useful in the treatment of associated conditions. The only antidepressant to be avoided is Wellbutrin (and Zyban) because of a risk of seizures in those suffering from anorexia and bulimia.

Recently, a new class of drugs refeired to as "atypical neuroleptics" has shown some promise in the treatment of anorexia. Olanzepine (Zyprexa) and Risperidone (Risperdal) are the two medications currently being studied from this class. When they are effective the drugs seem to act by relieving the anxiety around food and by facilitating weight gain.

Medications and Bulimia

In contrast to anorexia, many antidepressants have been found to be useful in the treatment of bulimia and binge eating disorder. Antidepressants when effective, decrease the urge to binge as well as the rate of bingeing and self-induced vomiting. Antidepressants work regardless of whether the person is depressed or not. As in the case of anorexia, antidepressants can also be used to treat clinically significant associated conditions such as, depression, anxiety and obsessive-compulsive disorder. Antidepressants may also decrease symptoms associated with bulimia such as impulsivity and mood swings even when they do not significantly decrease bingeing and purging.

Although antidepressants have a role to play in the treatment of bulimia, they are far from a magical solution. They rarely eliminate bingeing and purging completely and even in the cases where there is an initial dramatic response, the risk of relapse is high. In fact, several studies have found eating-disorder specific psychotherapies to be more effective than medication while others have found the combination of psychotherapy and medication to be most effective. At present, the approach we recommend in the absence of other complicating conditions is to start with individual or group psychotherapy. If after a few months there is no significant reduction in bingeing and purging, a trial with medications can be considered.

The best-studied antidepressants in the treatment of bulimia are the SSRIs but in practice, we find that antidepressants from other classes may also be helpful. There is no specific antidepressant that is more effective, although some people may have to try a few before they find the right one. Wellbutrin and Zyban must be avoided because of the risk of seizures, and Remeron is not recommended because it can increase appetite and cause weight gain.

General information about anttdepressants

Common side effects: SSRIs will often cause nausea, diarrhea, heartburn or indigestion at the beginning of treatment. Gastrointestinal side effects usually disappear after a few weeks of treatment and can be minimized bv eating before taking the medication. Other common adverse effects that may develop with any of the antidepressants currently in use include headaches, dizziness, decreased or increased sleep, restlessness, nervousness and increased sweating. In addition, the majority of antidepressants can produce the sensation of being cut off from one's emotions especially when taken at higher doses. Finally, these drugs may affect sexual functioning including decreased interest in sex and decreased ability to achieve orgasm. AB side effects are reversible when the drug is stopped and will improve if the dose is decreased. As a rule the antidepressants mentioned above do not affect the heart or the kidneys and can be taken safely by people who suffer from diabetes and most other medical conditions.

Interactions with other drugs: Some antidepressants interact with other medications leading to increased side effects and at times negative reactions. As a result, it is always recommended to tell doctors, phannacists and dentists that you are taking an antidepressant. Caution also has to be exercised when using homeopathic or herbal medicines. For instance, St. John's Wort should not be combined with antidepressants as it can lead to potentially toxic reactions.

PREGNANCY: Although no birth malformations have been linked to the use of antidepressants during pregnancy, it is best to try to avoid medications during pregnancy. Blood exchange between mothers and babies only begins at six weeks after conception so that people who are planning to get pregnant can wait till the pregnancy is confirmed before discontinuing the medication.

Answers to commonly asked questions

• Antidepressants are not addictive; they do not give you a "buzz", they do not induce cravings and you don't need to keep increasing the dose in order to get the same effect.

• Antidepressants do not make you "happy".

• Antidepressants have to be taken everyday.

• Antidepressants take several weeks to take effect and improvement is usually gradual with good and bad days.

• Antidepressants should not be stopped abruptly.

• Antidepressants have to be continued even after symptoms go away, the length of time that you need to stay on them varies and should be discussed with your doctor.

• Antidepressants are a tool not a crutch.