Independent Nurse: Clinical - Managing obesity in severe mental illness
Obesity Awareness Week runs from 13 to 19 March. Those with severe mental illness are notably at risk, says Dr Richard IG Holt.
Obesity reduces life expectancy by around nine years and accounts for 30,000 deaths in the UK per annum. In addition, overweight and obesity are associated with a number of metabolic and cardiovascular complications, musculoskeletal disease and several cancers, accounting for 18 million days sickness absence each year.1
There is compelling evidence that our society discriminates against fat people. This is damaging to the psychological well-being of obese individuals and may compound the effects of mental illness.
Mentally ill are at greater risk
Obesity is defined as a BMI greater than 30 and overweight as a BMI greater than 25. There are limitations to this measure, nevertheless across populations it correlates well with percentage body fat.
Measuring waist circumference can help identify those at high risk of metabolic complications (men gt100cm and women gt90cm), particularly if combined with a fasting triglyceride concentration.
Obesity is more common in those with severe mental illness than in the general population. One study found 89 per cent of people with schizophrenia were overweight, while 38 per cent had a BMI greater than 35.2
Reasons are multifactorial and include intrinsic factors such as reduced resting energy expenditure, and environmental factors such as low levels of physical activity and high caloric diets.
Research has shown that although people with schizophrenia consume fewer calories than those without, the percentage of energy obtained from fat is greater, while fibre, fruit and vegetable intake is lower.3,4 Furthermore, those with schizophrenia have a diet deficient in vitamins and antioxidants.3
Research has also shown that these individuals take less exercise.4 Inactivity and apathy are characteristic of schizophrenia, and may worsen as a result of hospitalisation, where opportunity for exercise is limited.
Significant weight gain may also occur during treatment with psychotropic drugs.5 Although there are differences between the various drugs in their tendency to cause weight gain, with the greatest mean gain being seen with olanzapine and clozapine, there is marked inter-individual variation and no antipsychotic can be considered weight neutral.
Despite these variations, it may be possible to identify individuals who are at high risk of weight gain. In a recent analysis, 15 per cent of patients who gained more than 7 per cent of their body weight rapidly during the first six weeks of treatment with olanzapine were more likely to gain significant weight over the long term.6
Managing the problem
The aim of a weight management programme is to improve health by reducing the morbidity and mortality associated with obesity rather than simply lowering weight and adiposity.7 Prevention of antipsychotic induced weight gain is also important because weight gain during treatment may lead to poor compliance.5
Any pharmacological intervention for obesity is second line to lifestyle modification. However, orlistat has been successful in treating antipsychotic induced weight gain in some cases.8,9 Sibutramine is contraindicated in people with severe mental illness.
Lifestyle modification has been neglected in the past in people with severe mental illness because of concerns that any intervention was doomed to failure.
But this therapeutic nihilism is unjustified as recent studies show that achieved weight loss is at least as great among this patient group as in the general population.10
Individuals should be advised to avoid extreme eating restraints and dieting, but type of food eaten and portion size should be addressed.
Reducing fat intake alone will lead to modest weight loss, while low energy foods may cut energy intake.
Exercise is important
Exercise plays a vital part in any weight management programme. People with severe mental illness should be encouraged to decrease the amount of time they spend sitting or occupied in sedentary activities. The total time spent active is more important than exercise intensity.
Advise patients to think of ways to include physical activity in their everyday lives, for example disembarking the bus one stop early. Physical activity should fit in with their daily life and ideally it should be pleasurable. The most appropriate type of exercise is one that will still be pursued a decade later.
Programmes that incorporate nutrition, exercise and some degree of behavioural intervention within a group setting are both pragmatic and inexpensive.2
It is possible that a one-to-one approach may be superior, but a group setting allows patients with severe mental illness to benefit from the support and motivation of others.
RESOURCES
??? National Obesity Forum:
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www.nationalobesityforum.org.uk
??? SANE:
www.sane.org.uk
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http://www.sane.org.uk/public%5fhtml...oE%5fReport%5f FINAL.pdf
REFERENCES
1. National Audit Office. Tackling obesity in England. London: TSO; 2001.
2. Ohlsen RI, et al. Schizophr Bull 2005;21:S567.
3. McCreadie R, et al. BMJ 1998;317:784-5.
4. Brown S, et al. Psychol Med 1999;29:697-701.
5. Haddad P. J Psychopharmacol 2005;19:16-27.
6. Kinon BJ, et al. J Clin Psychopharmacol 2005;25:255-8.
7. Holt RIG. J Psychopharmacol 2005;19:6-15.
8. Anghelescu I, et al. J Clin Psychopharmacol 2000;20:716-7.
9. Hilger E, et al. J Clin Psychopharmacol 2002;22:68-70.
10. Bushe C, et al. J Psychopharmacol 2005;19: 28-35.
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By Richard IG Holt
Dr Richard IG Holt works at the developmental origins of health and disease division at the School of Medicine, University of Southampton
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