Double Burden of Obesity and Depression (Women's Health Matters article) (Web resource; WHM resource) Author: Patricia Nicholson Organization: Women's College Hospital, Women's Health Matters Obesity is a complex disease with many health consequences, and can be difficult to manage. As researchers take a closer look at this condition, they have begun to explore possible links between obesity and depression. It can be difficult to tease out the roots of this relationship. Dr. Ahmed Hassan, who recently completed his University of Toronto psychiatry residency at Women’s College Hospital, discussed the overlapping causes and mechanisms of depression and obesity at a recent presentation at the hospital. The economic burden of obesity in Canada is now $4.3 billion per year, Dr. Hassan said. Its prevalence has doubled in the last three decades. In women, obesity risk increases with age and with chronic physical conditions. Low income levels and low education levels may also boost obesity risk. Clinical studies have suggested that not only does obesity increase the risk of depression, but depression may also increase the risk of obesity. It’s not unusual for patients to have both conditions, Dr. Hassan said. Energy balance The body stores fat when it takes in more energy (calories) than it burns through activity and exercise. The imbalance between caloric intake and output does not have to be huge to result in substantial weight gain over time. Dr. Hassan pointed out that a 10 per cent increase in caloric intake or a 10 per cent decrease in calories burned can result in a 30-pound weight gain in one year. There are several factors that can combine to cause those differences in intake or output that, over time, can result in obesity Being physically inactive means the body expends less energy: it’s not burning all of the calories it takes in. Just slowing down to a walking speed of under three miles per hour can make a difference: at that speed, walking burns fewer than four calories per minute. How much an individual eats depends on many things, including satiety: the sense of feeling full and not wanting to eat any more. But different individuals need different amounts of food in order to feel satiated. ‘Why do some people have room for dessert after a big meal?’ Dr. Hassan asked. The answer lies in a combination of psychological and hormonal factors that can influence metabolism. Neurotransmitters such as serotonin, dopamine and norepinephrine help regulate eating behaviour. Disruption in those neurotransmitters can result in abnormal appetite and abnormal eating patterns. Hormonal factors can also affect metabolism and eating habits. Some of the hormones implicated in metabolism include corticotrophin releasing factor, neuropeptide Y, gonadotropin-releasing hormone and thyroid-stimulating hormone. People can also become vulnerable to external cues, such as stressful situations or emotions, that make them reach for food. This behaviour eventually becomes self-sustaining. Dr. Hassan noted that recent research suggest that several elements in food – sugar, fat, flavour – all contribute to addictive food behaviours. Intertwined risks, shared causes Some studies have shown that obese people may have a higher risk of depression than people with a healthier BMI. Other studies suggest that depression may increase the risk of obesity. While it isn’t clear how this relationship works, the two conditions do share several common mechanisms and effects. Both conditions may involve a complex array of contributing causes, including genetic and behavioural issues. The close interplay of the brain’s hypothalamus and pituitary gland with the adrenal glands (known as the hypothalamic-pituitary-adrenal axis) is responsible for the regulation of a number of important hormones. Both obesity and depression can upset this system. Serotonin, dopamine and norepinephrine – the same neurotransmitters that help regulate eating behaviour – may play a role in obesity and in depression. In addition to their role in eating behaviour, these substances have also been implicated in mood disorders. Both obesity and depression can also interfere with the body’s control of the stress hormone cortisol, with glucose regulation and with how the body controls inflammation. In fact, both depression and obesity are considered ‘proinflammatory’ states. While inflammation is a natural response to injury and a part of the healing process, not all inflammatory responses are helpful. Many serious conditions – from diabetes and heart disease to cancer and rheumatoid arthritis – are linked to proinflammatory states. Treating two conditions The convoluted relationship between the two conditions means that treating patients who are both obese and depressed can be tricky. Sometimes the treatment for one condition can aggravate the second condition. For example, some drugs used to treat major depression, bipolar disorder and psychotic symptoms may induce weight gain. Medication adherence is often a problem with psychiatric drugs, and obese patients may be more than twice as likely as other patients to stop taking these medications. Similarly, some medications used to treat obesity are not recommended for use in patients with psychiatric illnesses or who are taking psychiatric drugs such as SSRIs (selective serotonin reuptake inhibitors, a class of antidepressant), MAOIs (monoamine oxidase inhibitors, another type of antidepressant) and antipsychotics. Screening is a key element in treating patients who are both obese and depressed, Dr. Hassan said. This should include exploring the following elements: the patient’s eating behaviour any history of eating disorders or related behaviours such as binge eating or purging body image body mass index (BMI) family history Treatment is dependent on a combination of diet and exercise, and often includes other elements such as prescription medication or psychotherapy to help clarify causes of eating habits. Behaviour modification therapy such as cognitive behavioural therapy (CBT) has been the most successful psychotherapeutic approach, Dr. Hassan said. Principles of healthy eating are a cornerstone of obesity treatment, but factors such as meal planning, mindful eating and understanding food labels can be keys to success. Exercise is an essential component, and may require looking at physical activity from a different perspective. The good news is that when an obese person exercises, she expends more energy and burns more calories for the same activity than someone with a lower BMI. Depression and obesity share common elements, and often occur in the same patient, Dr. Hassan concluded. Whatever combination of treatment options is used, it is imperative to address both conditions in the treatment plan. Version française :  Cliquez ici pour voir la description en français Purpose:  Consumer information/support; Health information Information Source:  Hospital/Clinic Geographic Origin:  Canada Language of Resource:  English Date Published:  July 20, 2010 Last Reviewed by Women's Health Matters:  July 23, 2010