Contrary to popular belief, depression does not usually lead to weight gain in the early stages, and depression is not more common among obese subjects than among the remainder of the population.

In cases of either depression or obesity, patients will benefit most and accept better any drawbacks after they are explained the goals and limits of treatment by their physician.

Weight gain is often associated with depression in the general and medical subconscious, whereas obese individuals are perceived to have a jovial personality that finds pleasure in overeating. What are the facts behind these contradictory pictures ?

Depression is not accompanied by weight gain, at least in the early stages. On the contrary, its main features are a characteristic triad of symptoms: insomnia, anorexia and weight loss. A weight loss of at least 5% over one month is one of the diagnostic criteria for depression. However, the signs and symptoms may be reversed. The incidence of the triad associating hypersomnia, overeating and weight gain was unknown until recently, and the triad itself has been reported primarily in particular forms of atypical depression, such as bulimia and especially seasonal depression (see box).

In response to a self-administered questionnaire, 8116 inhabitants of the province of Ontario, Canada, aged 15 to 64, showed that fewer than 10% had signs of depression. Among these patients, only 17% reported a reversed symptom triad, which was either permanent (11%) or intermittent (6%), and associated with weight gain. No distinct clinical feature, and in particular no specific psychological characteristic, could be found to identify this category of patients. Their comorbidity rate was much higher, as was their use of drug treatment and psychological therapy rate. The study did not provide a breakdown of the incidence of depression by type (in particular seasonal depression).

Although weight gain is not the rule during the initial phase of depression, it is nevertheless frequently observed when antidepressant therapy is initiated (Table 1), especially with tricyclic or similar antidepressants. For example, a placebo-controlled study showed a weight gain of 9 kg following a six-month treatment with amitriptyline. Some monoamine oxidase inhibitors (MAOI) may also cause overeating and consequently lead to weight gain. Recent inhibitors of serotonin recapture such as fluoxetine do not affect weight, but may promote transient weight loss at high dosage.

Most anti-psychotics cause weight gain as well. A weight gain of 5 kg has been reported in schizophrenic patients following the initial 12-week phase of chlorpromazine treatment, but weight returned to normal following the end of treatment.

Furthermore, Lithium too may be associated with an average weight gain of 10 kg over 2 to 6 years, while being unrelated to secondary treatment-induced hypothyroidism.

However, most sedatives or anti-anxiety agents do not affect weight.

Antidepressants probably act on the hypothalamus and nerve centres regulating hunger and appetite. It has been suggested that tricyclic antidepressants may cause intracerebral serotonin depletion. Indirect mechanisms such as dryness of the mouth, reduced physical, social and professional activity, may also contribute to weight gain.

Yet, most important is to choose the appropriate antidepressant on the basis of the patient's psychological status. The risk of gaining weight should remain a secondary consideration and may be prevented by recommending that patients avoid foods with a high sugar or high-calorie content. Once the patient's psychiatric condition is under control, discontinuing treatment is usually not enough to return to a satisfactory weight and a low-calorie diet is often necessary (Table 1).

* From Berstein J.G.
Table 1

Obese individuals were long thought to have a depressive personality or to suffer from psychiatric disorders that could explain why they were overweight, and overeating was seen as a reaction to psychological stress.

This concept did not withstand the test of the many recent controlled studies that failed to show a higher incidence of depression and psychiatric disorders among obese individuals than among people of normal weight. The apparent contradiction with previously reported data can be explained by improvement in assessment scales and also by the use of control groups.

Nevertheless, being overweight is experienced as very negative by patients and their family.

Rand and McGregor have shown that 47% of patients who lost weight following a surgery would rather become deaf, blind, dyslexic, diabetic, develop coronary heart disease or acne rather than regain all the weight lost. This extremely negative experience is further reinforced by the family environment that sees obesity as a sign of laziness, lack of will and cheating. Professionally, obese subjects often find themselves rejected by prospective employers; even the medical profession has a negative attitude towards their problems. Despite this unhelpful environment, severe depression is not more common among obese subjects than among the remainder of the population, but how they are perceived by others undoubtedly alters the mood of obese subjects. A common situation, especially in women nearing 50, it requires both psychological and nutritional support.

Studies conducted in the 50s and 60s suggested a link between dieting and depression. These results can be partly explained by poorly designed studies and the widespread use at the time of thyroid extracts and anorectics known to cause depression. Many recent controlled studies have invalidated the results of previous research. Indeed, contemporary studies have shown that not only is dieting not detrimental to psychological well-being, but it may even improve it as excess weight is shed. Neither cyclical variations in weight or putting on lost weight are associated with increased frequency of depression. There are of course some exceptions: chronic restrictive dieting and especially binge eating (see box). Highly restrictive diets (less than 1000 kcal/day) or massive weight loss secondary to surgical treatment may not be entirely harmless, especially among psychological fragile patients. Under these circumstances, and given the absence of data on the topic, caution is required when resorting to such exceptional treatments.

Beyond the information provided by studies and statistics, the search for the most appropriate therapeutic approach to a given patient must always consider potential adverse effects that should be anticipated and detected. Overlooking depression in a subject who gains weight or advising excessive caloric restriction to someone who shows disturbed eating behaviour may have disastrous results. These effects will be easier to control if they are first looked for and discussed with the patient at the initial consultation.

Professor Michel Krempf

Seasonal depression, the most common subtype of depression, is associated with a triad of reversed symptoms (hypersomnia, overeating and weight gain). First described by Rosenthal in 1984, it is characterized by depressive episodes that occur in the fall and winter and disappear in the spring and summer. Depression may be severe (6% of cases) and is accompanied by anxiety, irritability, loss of libido and social interactions.

Weight gain is primarily due to overeating of sweets. The syndrome is more common in women and its incidence increases with distance from the equator and shortened duration of daylight: 3% of New Yorkers suffer from the syndrome to varying degrees during winter. The only reported contributing factors are an increased incidence of family depression (80%) and the reduction in sun exposure (less then 10 hours per day). The syndrome cannot be explained by any hormonal abnormality. Serotonin deficiency, melatonin overproduction or abnormally low retinal sensitivity to sunlight have all been suggested. This has led to the use of phototherapy, with a consequent 30 to 40% reduction in weight gain, primarily due to a reduced intake of sweets.

Binge eating is a transient loss of control over food intake. It affects 4 to 5% of obese individuals (20 to 30% of those seeking specialized treatment) and may be a consequence of severely restrictive dieting. The disorder is diagnosed on specific criteria (Table 2), and may be accompanied by secondary depression due to the distress caused by the eating behaviour or attempts to control it. Restrictive dieting is always ineffective under such circumstances and often makes the depression worse. Only cognitive and behavioural therapies have demonstrated some efficacy in treating this disorder.

A. Recurrent episodes of binge eating An episode of binge eating meets the following two characteristics:
	1. Rapid consumption in a discrete period of time usually less than 2 hours, of a larger amount of food than most people ingest over the same period and under the same circumstances. 2. Feeling of a loss of control over eating behaviour during the episode (for example, feeling of not being able to stop eating or of not being able to control what is eaten or the amount eaten).

B. The episodes of binge eating are associated with at least three of the following features:

1. Eating more quickly than usual 2. Eating until unpleasant abdominal fullness develops 3. Eating small amounts of food in the absence of hunger 4. Eating alone (hiding to eat )because of the shame over the amount of food eaten 5. Eating large amounts of food on days when no meal has been planned 6. Self-depreciating thoughts, depression or guilt after having eaten too much 7. Eating large amounts of food when tired, anxious, lonely, depressed or feeling bored.

C. Binge eating is a cause of marked distress.
D. Binge eating occurs at least two days per week on average, over six months.
E. In contrast to bulimia, inappropriate compensatory purging behaviour (such as self-induced vomiting, use of cathartics, fasting or excessive physical exercise) is absent in binge eating.

Department of Endocrinology and Nutrition
University Hospital Centre, Nantes

* From: American Psychiatric Association DSM-IV Diagnostic and Statistics Manual of Mental Disorders - 4th Edition (International Edition, Washington, DC© 1995).