This is, to our knowledge, the first paper in Asia to explore the prevalence of psychiatric disorders in Asian patients who seek obesity treatment. We retrospectively reviewed 841 patients who received different obesity treatments, including non-surgical procedures and bariatric surgery. The patients underwent a standardized clinical evaluation using two questionnaires, and psychiatric referral when needed. Clinical evaluation revealed that 42% of patients had at least one psychiatric disorder. Mood disorders and anxiety disorders were the most prevalent.
Kalarchian et al.
 evaluated 288 bariatric surgery candidates. They found high prevalence rates of lifetime psychiatric disorders (66.3%) in these patients, even before surgery; 37.8% of patients had at least one psychiatric disorder. Rosenburger et al.
 in the US and Muhlhans et al.
 in Germany also found that patients had a high prevalence of psychiatric disorders before bariatric surgery (36.8%, and 72.6%, respectively). Our prevalence of any psychiatric disorder (54.1%) in the surgical group was lower than that of Kalarchian and Muhlhans, but higher than that of Rosenberger. Of all our patients receiving surgical or non-surgical treatment, the prevalence of any psychiatric disorder was 42%. This is not so different from the findings among Caucasians. We also found that mood disorders and anxiety disorders were the most prevalent classes of disorders, similar to the other studies. Eating disorders were the third most prevalent. We had a low frequency of substance abuse disorders (0.6%), and some patients had adjustment disorder and sleep disorders, which were not mentioned in the other three studies.
The differences in findings between our study and the other studies may be due to race, social factors and different study designs. The evaluation tool in the above three studies in the US and Germany was the structured interview, performed by well-trained psychologists. In our study, all psychiatric diagnoses were confirmed by board-certified psychiatrists. Our psychiatric evaluation is a part of the standardized pre-treatment evaluation process. However, patients might be worried about disclosing psychiatric problems if they thought it would affect their treatment, which may have lowered the prevalence of psychiatric disorders, as Muhlhans et al.
In our study, about 70% of patients were female. Females had a higher prevalence of mood disorders and eating disorders than males, but the males had more sleep disorders. There was no difference in anxiety disorder between the men and women. Similar outcomes were noted in our logistic regression models in Table
4. A previous community-based study, an international study in 13 areas worldwide involving 62,277 cases from the World Mental Health Survey
, found that obesity increased the odds ratio of depression and anxiety, especially in females. The possible mechanism may be that women have more psychological stress from the stigma of obesity, greater dissatisfaction with their body image, and more eating problems
Our finding is similar to that of Muhlhans’ study
, in which women had more prevalent psychiatric disorders than men, but inconsistent with that of Kalarchian’s study. In Asia, the criteria for obesity are lower than in Europe and the US, which means that people are generally thinner in Asia. No matter whether physical or socio-cultural factors are involved, women in Asia whose BMI is the same as that of men may have more psychological stress when dealing with obesity. In our study, patients in the surgical group were younger and had higher BMI than those in the non-surgical group. Eating disorders, especially binge eating disorder, is prevalent in bariatric surgery patients
 and has affected the outcome of weight loss after surgery
[27, 28]. Postoperative binge eating disorder can predict a poor surgical outcome. However, in our study, there were no differences between the two groups in terms of the prevalence of the other two important psychiatric disorders: mood and anxiety disorders. These two disorders may be affected by many different and complex psychosocial factors, not only BMI. Patients in the surgical group had a higher prevalence of several specific psychiatric disorders (adjustment disorder, binge eating disorder, and sleep disorders) than their non-surgical counterparts, but overall, psychiatric disorders were prevalent in both groups. This implies that people who seek obesity treatment, no matter the treatment they receive, suffer from similar psychopathological processes, with some exceptions.
The mood disorders, including bipolar disorder and depressive disorder, were the most prevalent class of disorders in our study. Patients with bipolar disorder are at a higher risk of being overweight and obese. The possible risk factors for weight gain in bipolar disorder patients include comorbid binge-eating disorder; the number of depressive episodes, treatment with medications associated with weight gain, low rates of exercise
, age, comorbid anxiety disorders, duration of depressive episodes, and history of hospitalization for depression
. The interventions used with obese bipolar patients should include better metabolite profile medication, adjunctive pharmacotherapy for weight loss, and the integration of lifestyle factors and weight-management counseling in the long-term care plan
[30, 31]. Depression may lower the patient’s level of energy and motivation, or change their appetite, making them less careful about their health. The relationship between depression and obesity is bi-directional, as seen in the meta-analytical evidence. Researchers found that obese persons had a 55% increased risk of developing depression over time, whereas depressed persons had a 58% increased risk of becoming obese (26). The possible etiology of the association between obesity and depression may be biological and psychological, but this requires further evaluation.
In this study, we found that higher BMI was associated with sleep disorders. Sleep disturbance in obese people may be related to anatomical factors, endocrinological factors, and metabolic circadian abnormalities of the physical condition
. About 70% of people with obstructive sleep apnea are obese. On the other hand, the prevalence of sleep apnea disorder among obese people is approximately 40%
. In previous research, attention deficit hyperactivity disorder (ADHD) was reported to be associated with obesity, binge eating behavior and sleep/alertness problems
. Cortese et al. proposed that obesity might be one of the factors associated with the sleep/alertness problem and manifest as ADHD-like symptoms. The association of obesity with ADHD is a novel area in need of attention and further study.
Our study had an adequate sample size (841 subjects, including 455 surgical patients and 368 non-surgical patients). We compared the characteristics and clinical correlates of psychiatric disorders in obese patients. Few studies have explored the differences before. The psychiatric disorders in this study were diagnosed by board-certified psychiatrists and hence had good reliability. However, some limitations of our study should be noted. The high rates of refusal of psychiatric evaluation may affect our results. One of the explanations may be that people in Taiwan do not understand that obesity is not only a physical disease, but also a possible mental disorder. They may worry about the stigma and are unwilling to visit a psychiatrist. All patients in our study were recruited from one university hospital. The community hospitals in Taiwan do not provide bariatric surgery, though some community hospitals treat obese people with non-surgical interventions. No known demographic difference between patients in community hospitals and university hospitals has ever been reported.
In recent years, many studies have focused not only on pre-treatment psychiatric problems, but also on post-treatment follow-up. Obesity treatment, including bariatric surgery, is still under development in Asia, and psychiatric involvement is imperative for a comprehensive treatment. Future studies should focus on the effects of ethnicity and culture, which are diverse in Asian countries.