Bipolar disorder and binge eating: What's the link?

Having one condition — either bipolar disorder or an eating disorder — may predispose a person to have the other. Although binge eating can occur as a part of other eating disorders, such as bulimia nervosa or binge eating disorder (BED), it can also happen independently. When binge eating does occur, researchers have discovered that it often appears around the time bipolar mood symptoms arise.

Additionally, both disorders share the following traits:

• begin early in life, around late adolescence or early adulthood
• are cyclical in nature
• can cause emotional reactivity and changes in energy levels and eating patterns

When researchers scoured 47 studies with over 30,000 participants as part of a 2021 systematic review, they discovered that:

• 12.5% of those diagnosed with bipolar disorder as their primary diagnosis also had BED
• 9.1% of those diagnosed with BED as their primary disorder also had bipolar disorder

Similar, but not as high, findings occurred between bulimia nervosa and bipolar disorder, with 7.4% of the individuals diagnosed with bipolar disorder having bulimia nervosa and 6.7% of those with bulimia nervosa having bipolar disorder.

One condition may affect the other

The conditions may be linked in that they might affect one another. For example, certain moods may trigger a binge eating episode. Some find that during mania episodes, they are more likely to binge eat than during periods of depression.

Researchers think this could be due to the emotional symptoms experienced during bipolar disorder that could make someone more likely to have weak impulse control or feel anxious.

During mania, a person’s impulsivity may increase, leading to binge eating. Alternatively, during a state of depression, someone may not feel inclined to eat, experiencing low appetite and energy. However, for some individuals, the opposite is true. Impulsive and anxious tendencies during mania lead to skipped meals and forgetting to eat. When they enter a period of depression, they may feel inclined to eat more of a specific type of food or have cravings. Some researchers theorize binge eating during depression could be a maladaptive coping skill.

Due to recent understandings of how one condition may affect the other, some researchers propose that a diagnosable subtype, such as “bipolar disorder with an eating disorder,” is necessary.

Although there is no concrete link, researchers have proposed the following theories:

Genetics

A 2018 study found suggestive evidence of an association between bipolar and BED due to variance in the gene PRR5-ARHGAP8. Variations in this gene have a link to both BED and bipolar disorder. Several bodily processes are supported by this gene, including energy level stability and monitoring of food intake. Additionally, both disorders have high heritability — transmissible from parent to child.

Brain-derived neurotrophic factor (BDNF)

BDNF is a brain and spinal cord protein. Although it has many roles, a few important ones are energy, mood, and appetite balance. BDNF can suppress food intake, helping to regulate a person’s appetite.

However, levels decrease during a mood episode, leading to a disruption in the suppression of a person’s appetite and mood. As a result, binge eating can occur, especially if a person is diagnosed with a mood condition such as bipolar disorder. The fluctuations further highlight the connection between mood episodes as triggers for impulsive or binge eating.

Side effects of medication

Doctors may recommend medication for the treatment of bipolar disorder. Common medications can include antipsychotics. However, antipsychotics may contribute to disordered eating. Some affect the brain’s reward system, increasing activity in the area linked with food rewards.

Research has also found that prolonged antipsychotic use affects satiety, decreasing a person’s ability to recognize when they are full. As a result, weight gain can occur. Experts theorize that in some cases, weight gain due to antipsychotics may further the cycle of purging and binging.

Self-soothing

It is common to turn to food when a person feels uncomfortable emotions. However, for those with bipolar disorder, binge eating may be a maladaptive coping skill during manic or depressive episodes.

In one study conducted in 2021, participants with bipolar disorder reported eating not only when they wanted to feel comforted but also to feel more in control during quick mood changes and to comfort themselves when they felt fatigued or disinterested in life.

Trauma

Researchers believe trauma may be a risk factor for both bipolar disorder and eating disorders. Traumatic disorders, such as post-traumatic stress disorder (PTSD) and binge eating, are highly comorbid, meaning they occur alongside each other. Another study focusing on teenagers and young adults discovered that among participants with bipolar disorder and an eating disorder, 20% also had PTSD.

Binge eating in those with trauma may be another way to exercise control through food or use food to cope with extreme emotions.

Although it can be common for bipolar disorder and eating disorders to occur alongside each other, comorbidity of these conditions can cause adverse mental effects, such as:

• anxiety
• mood instability
• psychosis
• suicidal thoughts

This may be because poorer physical health often coincides with poorer mental health in those with bipolar disorder. Eating disorders experienced simultaneously with bipolar disorder may also be more severe. Generally, those with both bipolar disorder and eating disorder report more severe:

• body dissatisfaction
• worsened impulse control
• decreased awareness of satiety and hunger cues
• weight concerns
• eating concerns

Overall, the worsened symptoms of bipolar disorder and eating disorder can cause a reduced quality of life. Relationships can be challenging to maintain when loved ones do not understand what a person is going through. Tasks such as preparing food or grocery shopping can become sources of extreme stress. The person may feel tired or stressed when trying to avoid binge eating or shifts in mood.

Willpower is usually not enough to treat mental disorders, sometimes leading to increased emotional distress during a mood shift or binge eating episode.

However, treatment may benefit both conditions, improving a person’s quality of life.

As one condition may affect the other, it is important to treat both.

For bipolar disorder

Bipolar disorder often relies on both medication and talk therapy to manage symptoms. As a result, there is a risk that some bipolar medications can cause disordered eating. It is helpful for a person to talk with a doctor about other drug options if adverse side effects occur.

For binge eating

Binge eating treatment primarily consists of therapy as opposed to medication. Therapy may address the following:

• past trauma and how to work through it
• disordered thinking surrounding food
• food insecurity triggers
• creation of a routine to balance eating, activity, and sleep

In addition to one-on-one therapy, disordered eating support groups may also prove beneficial.

For both conditions

Though researchers theorize one condition plays a role with the other, they need more research to learn how they affect one another. The conditions together can be particularly complex as those with bipolar disorder taking antipsychotic medications are typically not part of binge eating studies due to the likelihood of their medication adversely affecting appetite and weight. Similarly, bipolar disorder studies usually focus on weight loss and obesity instead of binge eating.

A few recent studies are exploring effective treatments for both conditions. For example, a 2021 study found that participants with both BED and bipolar disorder benefited from dialectical behavior therapy (DBT), while cognitive behavioral therapy (CBT) may lessen depression in those with BED.

People living with bipolar disorder may be more likely to experience episodes of binge eating. Although there is no clear link, various theories may explain how one condition affects the other. However, experts know that when the conditions co-occur, the symptoms and treatments can be complex.

Therefore, a combination of strategies works well, including psychotherapy and medication. It would be beneficial if a person with both conditions could work with their healthcare team to discover the best treatment plans, focusing on holistic care for the many facets of these conditions.