The link between eating disorders & OCD has been documented since 1939. Kaye et al (2004)* concluded that 64% of eating disorders sufferers had at least one concurrent anxiety condition and 41% of these had OCD specifically. An article by Neziroglu & Sandler** differentiated between OCD and eating disorders for the purposes of diagnosis according to behavioural and motivational/obsessional criteria. I believe that a comprehensive diagnosis is more complicated and cannot be reduced to these two criteria alone. It will hinge on evaluating possible OCD according to the presenting food-related behaviours and obsessions together with past or present secondary OCD symptoms. In the case of food related symptoms, even assessing between OCD sub-types becomes critical since, if contamination OCD is suspected (avoiding certain 'contaminated' foods, e.g., oils or fats), then successful treatment would rely on differentiation between contamination (I will be contaminated) or a contamination-responsibility sub-type (I will contaminate others) which require different emphases.
Neziroglu and Sandler differentiate between bulimia and anorexia in terms of an eating disorder but not with regard to their relationship with OCD. In my professional experience, bulimia can exist alongside OCD (co-morbid) but is more likely to be independent whereas anorexia can exist alongside OCD but is more likely to be interdependent. In the latter case, the OCD diagnosis is frequently marginalised or mistakenly overlooked as anorexia alone.
In anorexia & bulimia, the individual’s obsessions revolve around body image, weight, dietary control and fears of rejection and behaviours revolve mainly around highly controlled eating and exercising. In the case of an OCD eating disorder (OCDED?) the obsessions are varied, as are the behaviours which may not be limited to controlling food. Clients who have been diagnosed with anorexia may actually have contamination issues regarding certain foods. As an example, a female client had an obsession regarding oils and fats triggered by a traumatic event at the dinner table as a child. Her OCD lead to her initially avoiding just oils in her diet but as her condition progressed she began to exclude ‘oil or fat-contaminated’ foods such as cheeses, meats, nuts, eggs, cream, butter, ice cream, etc. Unchecked, avoidant behaviours start with avoiding high risk factors and quickly encompass low and often, no risk factors. In any case, her weight loss was significant. When years of therapy targeting body image and self-worth had limited outcome, other food-unrelated OCD symptoms lead her to treatment for her OCD and her food avoidance was correctly assessed as an OCD symptom. Therapy specific to her obsession regarding oils and fats was effective in her long-standing recovery. This was contamination OCD.
A male client had similarly been treated for an eating disorder when he reached a dangerously low BMI. When he expressed his fears that eating would ‘change him for the worse’ he faced 10 years of therapy tackling control, body image and self-worth. Eventually when a psychiatrist probed deeper, it was discovered that he was worried it would ‘change him in to a bad person’ – the feared change wasn’t physical. He was then mistakenly diagnosed with psychosis before a relative read an article about OCD describing this obsession regarding being a bad person as the basis of many OCD symptoms. This client feared he would change in to a bad person and do bad things to others. This was contamination/responsibility OCD.
In my experience, other food control obsessions might be:
1.Avoiding food because of a traumatic event involving a person who is overweight - contamination
2. Controlling food during pregnancy – responsibility
3. Avoiding food or drink due to fears of being poisoned or drugged – contamination
4. Avoiding food or drink due to fears of vomiting, defecating or urinating - shame issues
5. Avoiding food without specific fears but because the habitual rituals of eating have become distressing and time consuming
6. Avoiding food because a person in the household is contaminated – contamination
7 Avoiding food due to hypochondria
As I have always maintained, OCD is not a linear condition. It is complicated and often bizarre with a cross matrix of obsessions and compulsions, some of which may resemble other conditions. Not only that but other conditions can exist alongside and be independent or interdependent. The science of multi-diagnoses is improving, as are therapeutic approaches, nevertheless, a comprehensive assessment of an eating disorder should include an OCD screening for reasons stated above. In addition, an optimum assessment must also include other possible secondary sub-types of OCD as well as the food-specific obsessions and compulsions. It is possible, but rare, that OCD presents as just one obsession and behaviour. It is much more likely that the evidence for an OCD eating disorder assessment will lie with other past or previously presenting OCD symptoms, however covert. In short, to achieve much better outcomes, the science of assessing and treating co-occurring disorders away from the serial model must incorporate a wider and more comprehensive assessment at the outset narrowing to more specific and specialised treatment in the long-term. More about this later.
*https://iocdf.org/expert-opinions/expert-opinion-eating-disorders-and-ocd/
**Kaye WH, Bulik CM, Thornton L, Barbarich N, Masters K, “Comorbidity of anxiety disorders with anorexia and bulimia nervosa.” Am J Psychiatry, 2004; 161 2215-2221. 2. Yaryura-Tobias JA, & Neziroglu F (1983). “Obsessive Compulsive Disorders Pathogenesis Diagnosis and Treatment.” New York Marcel Dekker