Management of obesity in the psychiatrist's office
Obesity is an epidemic in the developed countries, and the rest of the world is quickly catching up. Patients with severe mental illness (SMI) suffer from two to three times higher rates of obesity , and this has translated into much higher rates of obesity-related morbidity and premature mortality in this population . This raises the question if obesity management should be added to the expanding responsibilities of psychiatrists. Our answer to this question is a resounding “Yes”.
First, obesity is a behavioral problem that involves eating too much and moving too little. The most robust evidence for effective management of obesity is for behavioral interventions, usually referred to as lifestyle interventions. These are typically based on principles of cognitive behavioral therapy and social cognitive change. Psychiatrists are experts of behavioral change and are equipped with the tools to employ against this disease.
Second, it has become abundantly clear that psychiatric medications, especially antipsychotics, play an important role in the increased rates of obesity among patients with SMI . While it is preferable to prevent the excess weight gain due to psychotropic medications, this is not always possible. Many patients will already be overweight or obese at the initial visit to a psychiatrist. Management of overweight and obesity is therefore as much a part of psychiatrists' duty as the management of other medication side effects, ranging from movement disorders to impaired sexual function. Obesity is also associated with increased rates of depression, decreased quality of life, and increased stigma in this population. Obesity is a calamity that needs to be managed in the psychiatrist's office.
OBESITY AS A MEDICATION SIDE EFFECT
The first task of weight management is not to exacerbate the problem through medication side effects. There is abundant evidence that switching from a weight-inducing medication to one that has lower weight gain liability or is weight neutral can produce clinically significant weight loss. A switch should be considered for any patient who is obese or who has gained a clinically significant amount of weight (>5% of body weight), or who has other evidence of severe metabolic dysfunction (e.g., poor diabetes disease control). Such switching between antipsychotic medications can result in weight loss of 2-3 kg after 24 weeks, and also clinically significant changes in non-high-density lipoprotein (non-HDL) cholesterol, triglyceride and glucose levels. In the context of close clinical monitoring, switching can be tolerated without increased risk of psychiatric hospitalization or significant psychiatric symptom exacerbation .
There are several straightforward principles of management of the side effect of weight gain. Any medication that blocks central histamine-1 (H1) receptors can increase appetite and produce weight gain. Such medications include the antipsychotics olanzapine and quetiapine; the antidepressants mirtazapine and several older tricyclic antidepressants; and central antihistamines that are used to treat anxiety, such as hydroxyzine. These medications should be avoided as initial treatments, or switched to alternatives with lower weight gain liability whenever possible. Many of these medications also block serotonin 2c (5HT2c) receptors, which also induces appetite (though to a lesser extent than H1 blockade). This may explain why some second-generation antipsychotics which are not antihistaminic may cause significant weight gain in some patients.
Dopamine-2 (D2) receptor blockade has also been associated with significant weight gain, especially among treatment-naïve patients presenting with a first episode of psychosis . Since all antipsychotic medications in current use are D2 blockers, it is essentially impossible to avoid D2 blockade when prescribing pharmacotherapy to patients with schizophrenia and other psychotic disorders. However, newer antipsychotic agents are increasingly used for augmentation or as first line medications in the treatment of bipolar disorder and other mood disorders. There are more weight neutral strategies for treatment of these conditions, and such options should be tried first, especially among patients who are already overweight. Mood stabilizers such as lithium and valproate, although weight inducing themselves through unknown mechanisms, are associated with less weight gain than antipsychotic agents. Many newer antidepressants are weight neutral, or may even be associated with weight loss, as in the case of bupropion.
Weight loss through a healthy lifestyle (increased physical activity and decreased caloric intake) can prevent or delay the onset of type 2 diabetes and cardiovascular disease, particularly among high-risk individuals. Even small reductions in body weight can lead to substantial improvements in a metabolic risk profile: weight loss of as little as 5% of initial body weight can prevent or delay the onset of diabetes, hypertension, hyperlipidemia, and cardiovascular disease .
Routine weight monitoring provides the opportunity for psychiatrists to counsel patients about nutrition and physical activity. Scales are available around the world and are a cheap tool that should be a mainstay in every psychiatrist's office. Several minutes of every psychiatric visit should be reserved for weighing the patient, which is itself an effective weight loss tool. Patients (and their families) should be educated about healthy lifestyles. This education does not need to be administered by a nutritionist or other specialist; it can effectively be provided by mental health clinic staff. Brief counseling by primary care clinicians can lead to changes in patient health behaviors (e.g., increased exercise or vegetable consumption) . Similar risk assessment and brief advice about behavioral risk should be incorporated into routine psychiatric practice. The patient's nutritional status and previous weight loss efforts should be reviewed. Suggestions should be offered at every visit, and might include: a) identifying one high calorie dietary component such as a sugared beverages or fried chicken, and suggesting healthier alternatives (diet soda or baked chicken); b) incorporating increased physical activity into daily routine, such as taking stairs instead of elevators, or walking to work; c) alerting patients against non-hunger related calorie intake, such as snacking or emotional eating or eating in response to stress; d) stimulus reduction, such as storing high calorie foods out of sight and out of reach.
An obesity medication should not be started without first trying a structured lifestyle program, and lifestyle programs need to be continued after any obesity medication is started. Manualized lifestyle interventions, such as the Diabetes Prevention Program, have substantial evidence of effectiveness in promoting weight loss and can be delivered in community settings by lay persons . Such interventions have been adapted for patients with SMI, and several large randomized controlled trials have demonstrated their efficacy . At least seven interventions are ready for implementation, but to date, they have not been widely disseminated. As up to 40% of participants can lose a clinically significant amount of weight (5% of baseline weight) through participation in such programs , their implementation may represent a tremendous return on a small investment for public mental health agencies. These evidence-based interventions to promote weight loss and decrease diabetes risk must be made available at community mental health centers.
Among individuals who are not able to lose or sustain sufficient weight loss to improve health with lifestyle interventions alone, adjunctive pharmacotherapy can help . But pharmacotherapy options for weight loss for persons with schizophrenia or other psychotic disorders are very limited. Orlistat (a pancreatic lipase inhibitor) blocks fat absorption in the intestines but does not appear to be effective among patients with schizophrenia. Sympathomimetics (diethylpropion and phenteramine) are associated with a risk for psychosis exacerbation, and are relatively contraindicated. The use of topiramate, an anti-seizure medication that has been associated with weight loss when used in patients with schizophrenia, may be limited by the neurocognitive side effects and the risk of metabolic acidosis.
The safety and efficacy of promising newer agents (lorcaserin and the combination of naltrexone and bupropion) among patients with schizophrenia are unknown . Lorcaserin, a 5-HT2c agonist, is marketed with a warning for neuroleptic malignant syndrome and serotonin syndrome when used in combination with psychotropic medications, although no such cases have been reported in the literature to date.
The medication with the strongest evidence for diminishing the adverse effects of obesity among patients with schizophrenia is metformin, a medication without a Food and Drug Administration (FDA) indication for weight loss. Like with lifestyle interventions and antipsychotic switching, typical weight loss with metformin is 3 kg at 16 weeks, which is relatively modest and similar to its effect for non-psychiatric patients . Metformin, however, also reduces other risk factors for cardiovascular disease, such as triglyceride levels, and may prevent or delay the onset of type 2 diabetes.
Given that metformin appears to be well tolerated by most patients, it should be considered for clinically stable overweight outpatients with schizophrenia or schizoaffective disorder, titrated up to 1000 mg twice daily if tolerated. There are factors that limit its widespread use, however. Care must be taken to minimize the risk of lactic acidosis, and metformin should not be prescribed to patients at increased risk: those with congestive heart failure, renal impairment, hepatic disease, or current alcohol abuse or dependence. Second, treatment duration has not been well defined. FDA labels recommend discontinuation of lorcaserin or phenteramine plus topiramate after 12 weeks if the threshold of less than 5% weight loss is not met, so this might guide the management of metformin. But patients may need longer treatment (than the 16-24 weeks of typical clinical trials) if they do have an initial weight loss. Concerns have been raised recently, however, about the risks of metformin use over longer periods. The evidence suggesting that its chronic use increases the risk of Alzheimer's disease  suggests that more work is needed to define an algorithm for weighing this risk with that of cardiovascular disease in any individual or subgroup of patients.
Bariatric surgery is indicated for patients with severe obesity (body mass index ≥ 40 kg/m2) or medically complicated moderate obesity (body mass index ≥ 35-39.9 kg/m2) and who fail lifestyle and pharmacologic intervention. Long-term studies show that the procedures result in significant weight loss (more than 50% of baseline body weight), recovery from diabetes, improvement in cardiovascular risk factors, and a 23% reduction in mortality .
The limited data about the efficacy and tolerability of bariatric surgery among patients with SMI suggest that outcomes are comparable to individuals without SMI . Psychiatrists need to understand how (and when) to advocate for their patients to be considered as surgical candidates. We often know our patients better than any other medical providers, and are in the best position to assess motivation, adherence, and the impact of psychiatric illness on the ability to sustain complex self-care regimens. Moreover, we can provide longer-term follow-up for monitoring of psychiatric symptoms that might emerge after the immediate post-operative period and surgical follow-up.
Persons with SMI represent a health disparities population with respect to obesity and other cardiovascular risk factors. Obesity represents the obvious starting point for an expansion of the scope of practice of psychiatrists to address these health disparities, given the ease of monitoring outcomes (weight and body mass index), the availability of effective treatments, and the large potential impact on outcomes of changing health behaviors.
Obesity is a chronic illness. Even among patients who lose weight, long-term weight maintenance is difficult. Weight regain is the norm, even with continued lifestyle modification. There is a need for constant vigilance to sustain behavior changes in the face of environmental pressures to regain weight. Patients with SMI may additionally face biologic factors that increase weight regain, including second-generation antipsychotic medications. Psychiatrists need to do more than acknowledge the poor health outcomes among these vulnerable patients; they need to work actively to prevent and address them.