In February, University of California - San Diego held a conference on the translation of new eating disorders research into innovative treatment approaches. One of the highlights of the conference was Dr. Walter Kaye, Director of the UCSD Eating Disorders program discussing:
“When Good Traits Go Bad: Clues to More Effective Treatments for Eating Disorders”
Some of the key areas that Dr. Kaye discussed included questions of how temperament is encoded in the brain and what implications this might have for treatment. Common traits in Anorexia Nervosa (AN) include anxiety, perfectionism, self-critical and obsessive thinking. These are often present before the start of the eating disorder. There is no one “brain center” for anxiety or AN, with these disorders being encoded both at the molecular level (e.g. neurotransmitters) and the neurocircuit level (linkage of several brain centers).
The balance between different neurocircuits is key, especially between the “limbic” circuit, which is involved in feelings of reward (positive emotion and immediate gratification), and the “cognitive/executive” circuit which is involved in planning, weighing long-term consequences and inhibition. There may be an altered balance between these circuits in AN, so that the cognitive/executive circuit is excessively dominant over the limbic circuit, resulting in anxiety, perfectionism, inhibition and over-control. The reduction of eating in AN may be a way to correct this imbalance in the brain so as to reduce anxiety. Conversely, in BN, it may be overeating that reduces anxiety and depression.
The altered balance in AN may reflect not only exaggerated activity in the cognitive/executive circuit (increased anxiety) but also decreased response to positive experiences (decreased reward) in the limbic circuit. This can be seen in AN brain imaging research in which there is an altered physical response in certain brain areas to experiences that would normally be more rewarding, such as winning money. At one level the brain functions with a balance of different neurocircuits. Within each neurocircuit, activity is generated by a balance of neurotransmitters (chemical messengers). One of the most important for reward is dopamine – however a “paradoxical” response is seen in AN. In controls, amphetamine, which results in dopamine release, causes a euphoric response. In AN, however, it results in anxiety rather than pleasure.
What implication does this AN neurobiology of “less fun, more fear” have for treatment? The altered balance between decreased reward and increased anxiety limits the efficacy of traditional psychotherapy because it is difficult to learn new behaviors or maintain motivation for change. Approaches that might help include psychoeducation, structuring of the environment (as in Family Based Treatment) and skills based therapies. Development of constructive coping strategies can help one to tolerate uncomfortable sensations and “move on” rather than obsess. Finally, medication may have a role, especially atypical antipsychotics, which block dopamine receptors. These may decrease the anxiety producing effects of dopamine during feeding in AN.