Anxiety often, but not always, precedes the onset of an eating disorder.  An intense focus on food, weight, and exercise can become the focus of one's anxiety or can temporarily relieve these symptoms by creating a false sense of control.  In turn, malnutrition caused by an eating disorder can exacerbate anxiety symptoms due to hypervigilance brought on by our brain's strong instinct to survive by remaining alert for nourishment.   For individuals with the particular neurobiology of anorexia nervosa, a negative energy balance (more nutrition expended than consumed) actually has an (anxiolytic (anxiety-reducing) effect.  When anxiety doesn't precede an eating disorder, these symptoms can emerge later as an intense fear of weight gain and drive for thinness take over much of the individual's focus.  For these reasons, it is crucial that anxiety symptoms are treated along with the eating disorder; particularly since the two are closely related and common issues are addressed to address the underlying factors associated with both. 

Disordered eating behaviors commonly co-occur with mood disorders, particularly in women.  Many similar risk factors exist between eating disorders and mood disorders. Some individuals with mood disorders may develop maladaptive behaviors revolving around food in an attempt to manage symptoms related to the mood disorder itself. For example, a person who is struggling with major depression may use food as a comfort or distraction from distressing emotions.  Alternatively, someone who experiences a reduction in appetite due to depression may receive seconday reinforcement in the form of attention and praise from an environment that tends to applaud weight loss regardless of the reason.  This attention may lead to temporary improvements in mood that reinforce the eating disorder behaviors over time.  

Research shows that traumatic events, especially those involving violence between people, are significant risk factors for the development of a variety of psychiatric disorders, including eating disorders.  While the risk is greater for all eating disorders, it seems to be particularly high for the development of  binging and purging symptoms.  Further, individuals with eating disorders tend to be particularly sensitive to the effects of trauma and more likely to develop PTSD symptoms as a result.  

In much the same way abuse of certain substances is used to self-medicate, binge eating and/or purging appear to be behaviors that facilitate a reduction in the hyperarousal and anxiety associated with trauma and provide temporary relief to the individual by facilitating numbing  or even forgetting the traumatic experience.  These behaviors are reinforcing, making it difficult to break the cycle. As a result, traumatic experiences and their destructive effects are not effectively processed and continue to cause problems. In this way, trauma, PTSD, and eating disorders can be very much intertwined. 

Up to 50% of individuals with eating disorders have abused alcohol or illicit drugs, a rate five times higher than the general population. Up to 35% of individuals who abused or were dependent on alcohol or other drugs have also had eating disorders, a rate 11 times greater than the general population.  The substances most frequently abused by individuals with eating disorders or with sub-clinical symptoms include: alcohol, laxatives, emetics, diuretics, amphetamines, heroin, and cocaine.

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Eating disorders and substance abuse share a number of common risk factors, including brain chemistry, family history, low self-esteem, depression, anxiety, and social pressures. Other shared characteristics include compulsive behavior, social isolation, and risk for suicide.

Self-harm and eating disorders commonly co-occur. A recent review found that self harm, also known as non-suicidal self-injury (NSSI) occurs in 25-55% of eating disorder patients. Among patients with NSSI, 54-61% meet criteria for an eating disorder.  Both self-harm and eating disorder behaviors can be thought of as ways to escape, avoid or otherwise regulate aversive emotional states. People with self-harm and eating disorder behaviors often describe experiencing strong negative emotions, or emotions that feel out of control. Alternatively, they may describe self-harm as a physical representation of the pain they are in or as a way to feel something when their emotions feel completely shut off to them.  They also tend to judge themselves harshly for having feelings, or are afraid of their emotions, which leads them to feel desperate to find relief.  

Eating disorders are often accompanied with thoughts of suicide or suicide attempts. In fact, suicide is the most common cause of death among individuals with eating disorders. What's more, eating disorders have the highest mortality rate of any psychiatric disorder.  Often, individuals with eating disorders believe they aren’t good enough. They strive for perfection, an unrealistic ideal that they can never achieve.  The experience of repeatedly failing to meet this ideal may lead to increased feelings of hopelessness and suicidal thoughts.

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