Major depressive disorder is a risk factor for low bone mass, central obesity, and other medical conditions.

Major depressive disorder (MDD) is one of the most common psychiatric illnesses in the adult population. It is often associated with an increased risk of cardiovascular disease. Osteoporosis is also a major public health threat. Multiple studies have reported an association between depression and low bone mineral density, but a causal link between these two conditions is disputed. Here the most important findings of the POWER (Premenopausal, Osteoporosis Women, Alendronate, Depression) Study, a large prospective study of bone turnover in premenopausal women with major depression, are summarized. The endocrine and immune alterations secondary to depression that might affect bone mass, and the possible role of poor lifestyle in the etiology of osteoporosis in subjects with depression, are also reviewed, as is the potential effect of antidepressants on bone loss. It is proposed that depression induces bone loss and osteoporotic fractures, primarily via specific immune and endocrine mechanisms, with poor lifestyle habits as potential contributory factors.