Obesity and suicide risk in adults--a systematic review

There is evidence from prospective studies that obesity is positively associated with depression. In contradiction to this, however, a number of studies have revealed that the number of completed suicides decreases with increasing BMI. The objective of this systematic review is to elucidate this ambiguous research field, providing an overview of literature examining the relationship between obesity and risk of suicide in adults (>18 years).

Literature searches of the databases PubMed/Medline, PsychInfo, and Web of Sciences were conducted. Fifteen studies concerning completed suicide, suicide attempts and suicidal ideation met the inclusion criteria (seven prospective and eight cross-sectional studies).

Eight studies evaluating completed suicide reported an inverse relationship between BMI and suicide, meaning that obese people are less likely to commit suicide than people of low or normal weight, whereas one study showed no association and one showed a positive association. Studies about suicide attempts and ideation, on the other hand, found results that differed depending on gender. While obese woman reported more suicide attempts and suicidal ideation, obese men reported less attempts and thoughts.

The role of confounding variables such as age or psychiatric illness on suicide risk are discussed and remaining research questions are outlined, especially regarding the role of different underlying biological pathways and consideration of different classes of obesity.