How do antidepressants work in treating eating disorders?

How do antidepressants work in treating anorexia?

Antidepressants can be an effective medication for eating disorders, specifically for treating symptoms associated with anorexia. For example, SSRIs like fluoxetine have demonstrated some efficacy in reducing symptoms of depression and/or obsessive-compulsive disorder in patients with anorexia.^[2]

SSRIs and other antidepressant medications regulate neurotransmitters in the brain associated with mood (e.g., serotonin, norepinephrine, and dopamine). By elevating and regulating mood, antidepressants can play an essential part in a treatment plan designed to help anorexia patients get on the road to recovery.

However, antidepressants in the treatment of anorexia should be considered carefully by a medical professional, as symptoms of mood disturbance could be a result of malnutrition. Therefore, with proper weight restoration and nutrional intake, symptoms could resolve on their own.

Furthermore, SSRIs may be more helpful as part of a larger maintenance plan for patients that have returned to an appropriate body weight. Fluoxetine’s ability to regulate mood might help prevent relapse.^[2] However, it is not a do-all treatment that can be used alone. In fact, some studies have shown that fluoxetine offers no benefits over placebo.^[3] Still, SSRIs are commonly prescribed to patients with anorexia.

Other antidepressants might be prescribed instead, depending on the patient’s situation. These antidepressants include:

• Tricyclic antidepressants (TCAs) like amoxapine and imipramine enhance mood by enhancing the effects of serotonin and norepinephrine in the brain. TCAs have a high occurrence of side effects, though. These may include nausea, muscle stiffness or spasms, and changes in heart rate.^[4]
• Atypical antidepressants like mirtazapine and nefazodone improve mood using varying mechanisms of action. For example, some atypical antidepressants work on dopamine, while others work on norepinephrine or serotonin. Side effects include dry mouth, dizziness, and changes in sleep patterns, to name a few.^[5]

SSRIs and other antidepressants are best used with other treatments for anorexia, such as behavioral therapy, psychotherapy, and nutritional therapy.^[1] A multi-modal approach like this is the most productive in addressing anorexia. Of course, any treatments should be discussed with a mental health provider, a medical doctor, or other health professionals.

How do antidepressants work in treating bulimia?

As with anorexia, antidepressants can help treat symptoms of bulimia nervosa. Two of the antidepressants discussed above - SSRIs and tricyclic antidepressants - have the same effects in the brains of bulimia patients as they do in anorexia patients. That is, these medications operate on the neurotransmitters associated with regulating and even elevating mood.

This is equally important for patients with bulimia as anorexia. Approximately 63% of bulimia patients have major depression, with lifetime rates of major depression between 50 percent and 65 percent.^[6] Therefore, antidepressants may be essential in a more extensive treatment plan for addressing bulimia and comorbid disorders.

Researchers postulate that reduced serotonin levels might be a primary driver of bulimic behaviors.^[7]  Since some antidepressants - like SSRIs - work on serotonin, it stands to reason that they might help minimize urges to binge and purge by regulating serotonin levels in the brain.

Additional research seems to back up this claim. For example, one study demonstrated that fluoxetine reduced episodes of binge eating from 22 per month to four and reduced purging episodes from 30 to six per month in patients with bulimia.^[8] Other studies have shown that fluoxetine outperforms placebo treatments for reducing binging and purging.^[9]

Due to the success of fluoxetine in treating bulimia symptoms, it is currently the only medication approved by the FDA for the treatment of bulimia. However, other drugs might be prescribed if fluoxetine or tricyclic antidepressants don’t have the desired effect. These include:

• Serotonin and norepinephrine reuptake inhibitors (SNRIs) like duloxetine work much like SSRIs, though they block the reuptake of both serotonin and norepinephrine as a mechanism for improving and balancing mood.^[10]
• Modified cyclic antidepressants like trazodone increase the levels of serotonin and norepinephrine in the brain, which help improve mood.^[11]
• Anticonvulsants like topiramate have been tested as an option for minimizing binging and purging. However, research on the efficacy of anticonvulsants in this application has only occurred on a small scale.^[12]
• Monoamine oxidase inhibitors (MAOIs) alter serotonin and dopamine levels to reduce the urge to binge and purge.^[13]

How do antidepressants work in treating binge eating disorder?

Antidepressants for binge eating work in numerous ways. As discussed earlier, these drugs affect serotonin, norepinephrine, and dopamine levels in the brain, which affect everything from impulse control to appetite to mood.

By using an antidepressant as part of the treatment for binge eating disorder, mood, impulse control, and appetite improvements can help combat the urge to binge eat. Likewise, some antidepressants decrease appetite, which can help modulate the desire for people with this disorder to binge.^[14]

What’s more, antidepressants might help reduce the frequency with which people binge. Again, this might result from the improvement of comorbid conditions treated by antidepressants, like depression and anxiety.

Antidepressants aren’t the only medications prescribed for the treatment of binge eating disorder. Others include:

• Stimulants like lisdexamfetamine increase the levels of norepinephrine and dopamine in the brain. Currently, lisdexamfetamine is the only FDA-approved drug for binge eating disorder.^[15]
• Anticonvulsants like topiramate, can help reduce the urge to binge, as discussed earlier.

What is the best antidepressant for binge eating?

The only drug currently approved by the FDA to treat binge eating is fluoxetine. In this case, it’s specifically approved to treat bulimia, but doctors may prescribe it to address the binge eating symptoms of binge eating disorder as well.^[14]

Side effects of antidepressants

Antidepressants come with a host of potential side effects. These side effects vary from one medication to the next. However, common side effects amongst popular antidepressants do exist. These include:^[5]

• Sexual dysfunction
• Drowsiness
• Insomnia
• Dry mouth
• Blurred vision
• Nausea
• Headache
• Rash

In some cases, antidepressants might also cause increased anxiety, muscle tremors, and weight gain.

A severe side effect is an increased risk of suicidal ideation and suicidal behaviors in children and young adults.^[5] As such, pediatric and adolescent patients must be monitored closely for the emergence of suicidal tendencies when taking antidepressants.

Other treatment options for eating disorders

Fortunately, there are many treatments available other than medication for eating disorders. Popular eating disorder treatment options include:

• Psychotherapy, or general talk therapy, explores the underlying causes of the eating disorder. For example, the therapist might explore childhood traumas, internal conflicts, and motivations as potential causes.
• Cognitive-behavioral therapy (CBT) focuses on negative thought patterns and their relation to eating disorder behaviors. Moreover, it focuses on changing those negative thought patterns to address unwanted behaviors.
• Dialectical behavior therapy (DBT) explores self-acceptance, emotional regulation, and goal-setting themes. These and other activities help prepare patients for recovery and prevent relapse.
• Interpersonal psychotherapy (IPT) focuses on understanding psychological symptoms as a response to current life difficulties. The goal is to relieve these symptoms by improving a patient’s ability to function effectively in interpersonal situations.^[16]
• Family-based therapy (FBT) utilizes patients' connections with their loved ones to promote better eating habits, cease binging and purging, and restore weight to a healthy level. This type of therapy is most commonly used with children and adolescents with an eating disorder.^[17]
• Antipsychotic medications like olanzapine might be prescribed to address delusions that are sometimes associated with eating disorders (e.g., regarding perceived body shape and size). Additionally, some studies have shown antipsychotics to positively affect weight gain compared to placebo. Although the use of medication for weight gain is strongly disputed among practicing clinicians.^[18]
• Nutritional therapy focuses on educating patients about nutrition and building essential skills that promote positive behavior change. These changes focus on eating habits and the psychological, cultural, and social factors associated with eating.^[19]
• Hospitalization or residential treatment may be required for patients with a severe eating disorder who have not responded well to the above-mentioned treatments.