Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
9.1 Eating disorders
Eating disorders are more common in women than in men(119, 120). However, it is important that these disorders are not overlooked in men(3).
Eating disorders are a group of disorders that include anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified.
9.1.1 Anorexia nervosaAnorexia nervosa is characterised by a significant weight loss as a result of compromised eating, obsessive fears of being overweight and the voluntary pursuit of thinness. Anorexia is a chronic relapsing illness with one of the highest rates of mortality among psychiatric disorders.
Two main sub-types of anorexia nervosa include the:
- Restricting type where the individual restricts food intake.
- Binge eating/purging type where the individual alternates between binge eating and self induced vomiting, laxative or diuretic misuse(340, 341).
Management approachesStudies into the pharmacological treatment of anorexia are sparse and results for those that have assessed atypical antipsychotics and antidepressants are inconsistent.
In general, approaches to the management of people with anorexia nervosa involve(3, 342):
- Restoring weight to a normal range and medical monitoring of physical status. Specialist input may be required in the resuscitation of low weight individuals.
- Reducing the distorted perception of body image and related consequences.
- Medications can be prescribed if indicated. However, there is good evidence for non-drug treatment of anorexia.
Anorexia nervosa: A treatment guide for consumers and carers:
9.1.2 BulimiaBulimia is characterised by episodes of binge eating followed by compensatory behaviours to rid the body of calories and an obsession with weight and shape.
There are two main types of bulimia (reflecting the compensatory behaviours)(342):
- Purging type where the individual resorts to vomiting or uses laxatives, diuretics or enemas (340, 341).
- Non-purging type involving excessive exercising or fasting.
Management approachesIn general, approaches to the management of people with bulimia involve:
- Medical monitoring of medical status, particularly for electrolyte disturbance and the consequences of repeated purging behaviours.
- CBT which has been shown to be useful in the treatment of bulimia and is generally regarded as the first line of treatment****(343, 344).
- Different classes of antidepressants (TCAs, SSRIs, MAOIs) have shown good efficacy and tolerability in the treatment of bulimia(3, 342, 344):
- SSRIs (fluoxetine being the most widely studied) reduce bulimic symptoms by reducing the frequency of binge eating and purging as well as anxious and depressive symptoms****(344).
- High doses may be required to be effective with inadequate dosing responsible for discontinuation of treatment****(344, 345).
- Preliminary evidence exists for the additional efficiency of combined CBT and medication management although further studies are required to confirm this****(344).