In 2016, over 1.9 billion adults aged 18 years and older were overweight, of which over 650 million were obese. Studies show that two in five people with overweight or obesity are diagnosed with psychiatric disorders and that those with obesity are more likely to be diagnosed with mood disorders than those who are not obese.
While evidence exists for a bidirectional relationship between obesity and mental health, which diagnosis tends to come first remains a matter of debate. A better understanding of the timing at which both conditions occur could inform prevention strategies and treatments.
For the current study, researchers from Austria analyzed national health data from 2003- 2014. The data included over 3 million patients without obesity and 161,000 with obesity. Those with obesity received an average of 10.3 diagnoses during the study period, while those without received an average of 4 diagnoses. Obese individuals were also more likely to have more and longer hospital stays.
Ultimately, patients who received an obesity diagnosis were significantly more likely to receive diagnoses for multiple psychiatric disorders, including depression, psychosis, anxiety, eating disorders, and personality disorders. And crucially, for all co-diagnoses apart from psychosis, an obesity diagnosis was most likely to be received first.
The researchers further found that women with obesity were at a higher risk for all mental health disorders apart from schizophrenia and nicotine addiction. Younger people aged 30 and under with obesity were also more likely to develop mental health disorders than older groups.
"From a clinical point of view, these results emphasise the need to raise awareness of psychiatric diagnoses in obese patients and, if necessary, to consult specialists at an early stage of diagnosis," said one of the study’s authors, Michael Leutner of the Department of Medicine Division of Endocrinology and Metabolism at Medical University of Vienna, in a press release.
Sources: Science Daily, Nature