Our therapists, Dylan and I, seemed to be linking the obsessive side of our eating disorders to a sort of mental hyperactivity or busyness of mind. This seems a reasonable suggestion. Overthinking is a famous symptom of anorexia, and, although we’d starved ourselves into lassitude, we both tended to worry feebly at things, growling, like aged terriers with a bone. Dylan’s thorough, almost obsessive, adoption of his diagnosis seemed to bear this out.
Of course, the link between anorexia and OCD is well established. A fierce habit of restricting or purging or over-exercising is clearly obsessive-compulsive. Carrie Arnold explores the relationship between eating disorders and “obsessionality”, which she defines as “a pattern of thinking, in which someone focuses a lot on a particular subject or detail”.
There’s also a lot of chatter, online, surrounding a correlation between OCD and ADHD. The NHS website suggests that OCD may occur alongside ADHD in adults, this is called “Comorbidity”, and can complicate the diagnosis of either condition. Writing for The International OCD Foundation, Dr Amitai Abramovitch points out that both conditions are “characterised by abnormal brain activity in the same neural circuit”, the frontal-striatal system, that is responsible for “higher order, motor, cognitive and behavioural functions”. However, people with OCD show increased activity in this area, while ADHD people have decreased activity. Many other reputable online publications also make this link. MDedge (mdedge.com) claims that ADHD can be an “epiphenomenon of OCD” because an obsessive person’s “continuous and excessive attempts to control behaviour and thoughts” can be so distracting. Conversely, verywellmind.com claims that “ADHD can result in OCD-type coping skills.”
There is less written on a link between ADHD and Anorexia, but it seems likely that a three point, mutually reinforcing nexus could be at play in us. It’s not a solid, rigorously tested, causal link, just a suggested correlation. Both Dylan and I could become a little intense and unusually habit- or ritual-forming in our behaviours, and this extended to our restriction of our eating and, in my case, to my running. Carrie Arnold quotes Steven Tsao, who claims, “with anorexia, this obsessionality could be something they think about a lot, but they don’t actually mind thinking a lot about…In fact, some patients are happy to focus on [their eating disorder] and think a lot about it. I have patients that say, ‘if I don’t spend my day thinking about food, what else do I do with myself?’”
Arnold points how useful such obsessionality can be to somebody who is trying to control anxiety, as so many anorexics are. “Not only did anorexia mesh perfectly with my tendencies towards obsessionality (in fact my eating disorder probably enhanced my obsessionality), it also helped make me feel the world was simpler and easier to manage.”
And, of course, hunger and exhaustion make you more anxious, more in need of reassurance, more rigid in your thinking, as your brain starves, so all these symptoms and behaviours, all these tendencies, become more pronounced as anorexia’s jaws tighten on you, its teeth begin to bite.
 Decoding Anorexia, 2013, Routledge
 ibid, p65