The diagnostic workup typically includes complete medical and psychosocial history and follows a rational and formulaic approach to the diagnosis. Neuroimaging using fMRI, MRI, PET and SPECT scans have been used to detect cases in which a lesion, tumor or other organic condition has been either the sole causative or contributory factor in an eating disorder. "Right frontal intracerebral lesions with their close relationship to the limbic system could be causative for eating disorders, we therefore recommend performing a cranial MRI in all patients with suspected eating disorders" (Trummer M "et al." 2002), "intracranial pathology should also be considered however certain is the diagnosis of early-onset anorexia nervosa. Second, neuroimaging plays an important part in diagnosing early-onset anorexia nervosa, both from a clinical and a research prospective".(O'Brien "et al." 2001).

After ruling out organic causes and the initial diagnosis of an eating disorder being made by a medical professional, a trained mental health professional aids in the assessment and treatment of the underlying psychological components of the eating disorder and any comorbid psychological conditions. The clinician conducts a clinical interview and may employ various psychometric tests. Some are general in nature while others were devised specifically for use in the assessment of eating disorders. Some of the general tests that may be used are the Hamilton Depression Rating Scale and the Beck Depression Inventory. longitudinal research showed that there is an increase in chance that a young adult female would develop bulimia due to their current psychological pressure and as the person ages and matures, their emotional problems change or are resolved and then the symptoms decline.

Clinicians will often follow a diagnostic checklist to test whether or not an individual is exhibiting behaviors and characteristics that may lead to a diagnosis of ARFID. Clinicians will look at the variety of foods an individual consumes, as well as the portion size of accepted foods. They will also question how long the avoidance or refusal of particular foods has lasted, and if there are any associated medical concerns, such as malnutrition. Unlike most eating disorders, there may be a higher rate of ARFID in young boys, than there is in young girls.

There are numerous ways in which individuals can reduce emotional distress without engaging in emotional eating. The most salient choice is to minimize maladaptive coping strategies and to maximize adaptive strategies. A study conducted by Corstorphine et al. in 2007 investigated the relationship between distress tolerance and disordered eating. These researchers specifically focused on how different coping strategies impact distress tolerance and disordered eating. They found that individuals who engage in disordered eating often employ emotional avoidance strategies. If an individual is faced with strong negative emotions, they may choose to avoid the situation by distracting themselves through overeating. Discouraging emotional avoidance is thus an important facet to emotional eating treatment. The most obvious way to limit emotional avoidance is to confront the issue through techniques like problem solving. Corstorphine et al. showed that individuals who engaged in problem solving strategies enhance one's ability to tolerate emotional distress. Since emotional distress is correlated to emotional eating, the ability to better manage one's negative affect should allow an individual to cope with a situation without resorting to overeating.

One way to combat emotional eating is to employ mindfulness techniques. For example, approaching cravings with a nonjudgmental inquisitiveness can help differentiate between hunger and emotionally-driven cravings. An individual may ask his or herself if the craving developed rapidly, as emotional eating tends to be triggered spontaneously. An individual may also take the time to note his or her bodily sensations, such as hunger pangs, and coinciding emotions, like guilt or shame, in order to make conscious decisions to avoid emotional eating.

Emotional eating disorder predisposes individuals to more serious eating disorders and physiological complications. Therefore, combatting disordered eating before such progression takes place has become the focus of many clinical psychologists.

Previously considered a topic for further research exploration, binge eating disorder was included in the "Diagnostic and Statistical Manual of Mental Disorders" in 2013. Until 2013, binge eating disorder was categorized as an Eating Disorder Not Otherwise Specified, an umbrella category for eating disorders that don't fall under the categories for anorexia nervosa or bulimia nervosa. Because it was not a recognized psychiatric disorder in the "DSM-IV" until 2013, it has been difficult to obtain insurance reimbursement for treatments. The disorder now has its own category under "DSM-5", which outlines the signs and symptoms that must be present to classify a person's behavior as binge eating disorder. Studies have confirmed the high predictive value of these criteria for diagnosing BED.

According to DSM-5, the following criteria must be present to make a diagnosis of binge eating disorder. Studies have confirmed the high predictive value of these criteria for diagnosing BED.

A. Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:

1. Eating, in a discrete period of time (e.g., within any 2-hour period), an amount of food that is definitely larger than what most people would eat in a similar period of time under similar circumstances.

2. A sense of lack of control over eating during the episode (e.g., a feeling that one cannot stop eating or control what or how much one is eating).

B. The binge-eating episodes are associated with three (or more) of the following:

1. Eating much more rapidly than normal.

2. Eating until feeling uncomfortably full.

3. Eating large amounts of food when not feeling physically hungry.

4. Eating alone because of feeling embarrassed by how much one is eating.

5. Feeling disgusted with oneself, depressed, or very guilty afterward.

C. Marked distress regarding binge eating is present.

D. The binge eating occurs, on average, at least once a week for 3 months.

E. The binge eating is not associated with the recurrent use of inappropriate compensatory behavior as in bulimia nervosa and does not occur exclusively during the course of bulimia nervosa or anorexia nervosa.

Few studies to date have examined OSFED prevalence. The largest community study is by Stice (2013), who examined 496 adolescent females who completed annual diagnostic interviews over 8 years. Lifetime prevalence by age 20 for OSFED overall was 11.5%. 2.8% had atypical AN, 4.4% had subthreshold BN, 3.6% had subthreshold BED, and 3.4% had purging disorder. Peak age of onset for OSFED was 18–20 years. NES was not assessed in this study, but estimates from other studies suggest that it presents in 1% of the general population.

A few studies have compared the prevalence of EDNOS and OSFED and found that though the prevalence of atypical eating disorders decreased with the new classification system, the prevalence still remains high. For example, in a population of 215 young patients presenting for ED treatment, the diagnosis of EDNOS to OSFED decreased from 62.3% to 32.6%. In another study of 240 females in the U.S. with a lifetime history of an eating disorder, the prevalence changed from 67.9% EDNOS to 53.3% OSFED. Although the prevalence appears to reduce when using the categorizations of EDNOS vs. OSFED, a high proportion of cases still receive diagnoses of atypical eating disorders, which creates difficulties in communication, treatment planning, and basic research.

In individuals with autism, schizophrenia, and certain physical disorders (such as Kleine-Levin syndrome), nonnutritive substances may be eaten. In such instances, pica should not be noted as an additional diagnosis.

Few studies guide the treatment of individuals with OSFED. However, cognitive behavioral therapy (CBT), which focuses on the interplay between thoughts, feelings, and behaviors, has been shown to be the leading evidence-based treatment for the eating disorders of BN and BED. For OSFED, a particular cognitive behavioral treatment can be used called CBT-Enhanced (CBT-E), which was designed to treat all forms of eating disorders. This method focuses not only what is thought to be the central cognitive disturbance in eating disorders (i.e., over-evaluation of eating, shape, and weight), but also on modifying the mechanisms that sustain eating disorder psychopathology, such as perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties. CBT-E showed effectiveness in two studies (total N = 219) and well maintained over 60-week follow-up periods. CBT-E is not specific to individual types of eating disorders but is based on the concept that common mechanisms are involved in the persistence of atypical eating disorders, AN, and BN.

The 2017 update to the American version of the ICD-10 includes BED under F50.81. ICD-11 may contain a dedicated entry (6B62), defining BED as frequent, recurrent episodes of binge eating (once a week or more over a period of several months) which are not regularly followed by inappropriate compensatory behaviors aimed at preventing weight gain.

Emotional eating may qualify as avoidant coping and/or emotion-focused coping. As coping methods that fall under these broad categories focus on temporary reprieve rather than practical resolution of stressors, they can initiate a vicious cycle of maladaptive behavior reinforced by fleeting relief from stress. Additionally, in the presence of high insulin levels characteristic of the recovery phase of the stress-response, glucocorticoids trigger the creation of an enzyme that stores away the nutrients circulating in the bloodstream after an episode of emotional eating as visceral fat, or fat located in the abdominal area. Therefore, those who struggle with emotional eating are at greater risk for abdominal obesity, which is in turn linked to a greater risk for metabolic and cardiovascular disease.

There is no single test that confirms pica. However, because pica can occur in people who have lower than normal nutrient levels and poor nutrition (malnutrition), the health care provider should test blood levels of iron and zinc.

Hemoglobin can also be checked to test for anemia. Lead levels should always be checked in children who may have eaten paint or objects covered in lead-paint dust. The health care provider should test for infection if the person has been eating contaminated soil or animal waste. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, posits four criteria that must be met for a person to be diagnosed with Pica:

There are two main types of treatment given to those suffering with bulimia nervosa; psychopharmacological and psychosocial treatments.

With time the symptoms of ARFID can lessen and can eventually disappear without treatment. However, in some cases treatment will be needed as the symptoms persist into adulthood. The most common type of treatment for ARFID is some form of cognitive-behavioral therapy. Working with a clinician can help to change behaviors more quickly than symptoms may typically disappear without treatment. Also hypnotherapy may be used. In that it lessens the anxiety associated with food.

There are support groups for adults with ARFID.

Some researchers have also claimed positive outcomes in hypnotherapy.

Food addiction impacts relationships, especially those within the family. This is because the person with the addiction is vastly more involved with food than with people – it becomes their safest, most important and meaningful relationship. Other connections to friends and family take a back seat. This often leads to a deep sense of isolation from others.

Compulsive overeating is treatable with nutritional assistance and medication. Psychotherapy may also be required, but recent research has proven this to be useful only as a complementary resource, with short-term effectiveness in middle to severe cases.

Lisdexamfetamine is an FDA-approved appetite suppressant drug that is indicated for the treatment of binge eating disorder. The antidepressant fluoxetine is a medication that is approved by the Food and Drug Administration (FDA) for the treatment of an eating disorder, specifically bulimia nervosa. This medication has been prescribed off-label for the treatment of binge eating disorder (BED). Off-label medications, such as other selective serotonin reuptake inhibitors (SSRIs), have shown some efficacy, as have several atypical agents, such as mianserin, trazodone and bupropion. Anti-obesity medications have also proven very effective. Studies suggest that anti-obesity drugs, or moderate appetite suppressants, may be key to controlling binge eating.

Many eating disorders are thought to be behavioral patterns that stem from emotional struggles; for the individual to develop lasting improvement and a healthy relationship with food, these affective obstacles need to be resolved. Individuals can overcome compulsive overeating through treatment, which should include talk therapy and medical and nutritional counseling. Such counseling has been recently sanctioned by the American Dental Association in their journal article cover-story for the first time in history in 2012: Given "the continued increase in obesity in the United States and the willingness of dentists to assist in prevention and interventional effort, experts in obesity intervention in conjunction with dental educators should develop models of intervention within the scope of dental practice". Moreover, dental appliances such as conventional jaw wiring and orthodontic wiring for controlling compulsive overeating have been shown to be “efficient ways in terms of weight control in properly selected obese patients and usually no serious complications could be encountered through the treatment course.

As well, several twelve-step programs exist to help members recover from compulsive overeating and food addiction, such as Overeaters Anonymous and others.

Disordered eating can represent a change in eating patterns caused by other mental disorders (e.g. clinical depression), or by factors that are generally considered to be unrelated to mental disorders (e.g. extreme homesickness).

Certain factors among adolescents tend to be associated with disordered eating, including perceived pressure from parents and peers, nuclear family dynamic, body mass index, negative affect (mood), self-esteem, perfectionism, drug use, and participation in sports that focus on leanness. These factors are similar among boys and girls alike. However, the reported incidence rates of are consistently and significantly higher in female than male participants, with 61% of females and 28% of males reporting disordered eating behaviors in a study of over 1600 adolescents.

Disordered eating describes a variety of abnormal eating behaviors that, by themselves, do not warrant diagnosis of an eating disorder.

Disordered eating includes behaviors that are common features of eating disorders, such as:

- Chronic restrained eating.

- Compulsive eating.

- Binge eating, with associated loss of control.

- Self-induced vomiting.

Disordered eating also includes behaviors that are not characteristic of any eating disorder, such as:

- Irregular, chaotic eating patterns.

- Ignoring physical feelings of hunger and satiety (fullness).

- Use of diet pills.

- Emotional eating.

- Night eating.

- "Secretive food concocting": the consumption of embarrassing food combinations, such as mashed potatoes mixed with sandwich cookies. See also Food craving § Pregnancy and Nocturnal sleep-related eating disorder § Symptoms and behaviors.

It is difficult to gain an accurate picture of incidence and prevalence of self-harm. This is due in a part to a lack of sufficient numbers of dedicated research centres to provide a continuous monitoring system. However, even with sufficient resources, statistical estimates are crude since most incidences of self-harm are undisclosed to the medical profession as acts of self-harm are frequently carried out in secret, and wounds may be superficial and easily treated by the individual. Recorded figures can be based on three sources: psychiatric samples, hospital admissions and general population surveys.

The World Health Organization estimates that, as of 2010, 880,000 deaths occur as a result of self-harm. About 10% of admissions to medical wards in the UK are as a result of self-harm, the majority of which are drug overdoses. However, studies based only on hospital admissions may hide the larger group of self-harmers who do not need or seek hospital treatment for their injuries, instead treating themselves. Many adolescents who present to general hospitals with deliberate self-harm report previous episodes for which they did not receive medical attention. In the United States up to 4% of adults self-harm with approximately 1% of the population engaging in chronic or severe self-harm.

Current research suggests that the rates of self-harm are much higher among young people with the average age of onset between 14 and 24. The earliest reported incidents of self-harm are in children between 5 and 7 years old. In the UK in 2008 rates of self-harm in young people could be as high as 33%. In addition there appears to be an increased risk of self-harm in college students than among the general population. In a study of undergraduate students in the US, 9.8% of the students surveyed indicated that they had purposefully cut or burned themselves on at least one occasion in the past. When the definition of self-harm was expanded to include head-banging, scratching oneself, and hitting oneself along with cutting and burning, 32% of the sample said they had done this. In Ireland, a study found that instances of hospital-treated self-harm were much higher in city and urban districts, than in rural settings. The CASE (Child & Adolescent Self-harm in Europe) study suggests that the life-time risk of self-injury is ~1:7 for women and ~1:25 for men.

Cognitive behavioural therapy, individual therapy, and group therapy are often beneficial in helping people keep track of their eating habits and changing the way they cope with difficult situations.

There are several 12-step programs that helps overeaters, such as Overeaters Anonymous or Food Addicts in Recovery Anonymous and others.

It is quite clear through research, and various studies that overeating causes addictive behaviors.

In some instances, overeating has been linked to the use of medications known as dopamine agonists, such as pramipexole.

Rather than providing specific diagnostic criteria for EDNOS, the fourth revision of the "Diagnostic and Statistical Manual of Mental Disorders" ("DSM-IV") listed six non-exhaustive example presentations, including individuals who:

1. Meet all criteria for anorexia nervosa except their weight falls within the normal range

2. Meet all criteria for bulimia nervosa except they engage in binge eating or purging behaviors less than twice per week or for fewer than three months

3. Purge after eating small amounts of food while retaining a normal body weight

4. Repeatedly chew and spit out large amounts of food without swallowing

5. Do not meet criteria for binge eating disorder

Despite its subclinical status in "DSM-IV", available data suggest that EDNOS is no less severe than the officially recognized "DSM-IV" eating disorders. In a comprehensive meta-analysis of 125 studies, individuals with EDNOS exhibited similar levels of eating pathology and general psychopathology to those with anorexia nervosa and binge eating disorder, and similar levels of physical health problems as those with anorexia nervosa. Although individuals with bulimia nervosa scored significantly higher than those with EDNOS on measures of eating pathology and general psychopathology, those with EDNOS exhibited more physical health problems than those with bulimia nervosa.

Estimates of prevalence and gender distribution have varied widely via discrepancies in diagnosis and reporting. In American psychiatry, BDD gained diagnostic criteria in the "DSM-IV", but clinicians' knowledge of it, especially among general practitioners, is constricted. Meanwhile, shame about having the bodily concern, and fear of the stigma of vanity, makes many hide even having the concern.

Via shared symptoms, BDD is commonly misdiagnosed as social-anxiety disorder, obsessive-compulsive disorder, major depressive disorder, or social phobia. Correct diagnosis can depend on specialized questioning and correlation with emotional distress or social dysfunction. Estimates place the Body Dysmorphic Disorder Questionnaire's sensitivity at 100% (0% false negatives) and specificity at 92.5% (7.5% false positives).

Drunkorexia is not a medically diagnosed disorder therefore there is no specific treatment. However, as drunkorexia is a combination of two different disorders, binge drinking and eating disorders such as anorexia and bulimia the treatment will need to address both.

Research on treating BDD is limited. Yet anti-depressant medication, such as selective serotonin reuptake inhibitors (SSRIs), and cognitive-behavioral therapy (CBT) are considered effective. SSRIs can help relieve obsessive-compulsive and delusional traits, while cognitive-behavioral therapy can help patients recognize faulty thought patterns. Before treatment, it can help to provide psychoeducation, as with self-help books and support websites.

There is considerable uncertainty about which forms of psychosocial and physical treatments of people who harm themselves are most effective. Psychiatric and personality disorders are common in individuals who self-harm and as a result self-harm may be an indicator of depression and/or other psychological problems. Many people who self-harm have moderate or severe depression and therefore treatment with antidepressant medications may often be used. There is tentative evidence for the medication flupentixol; however, greater study is required before it can be recommended.