The association of weight gain with mood symptoms and functional outcomes following a first manic episode: prospective 12-month data from the Systematic Treatment Optimization Program for Early Mania (STOP-EM)

Objectives: Up to 75% of patients with bipolar I disorder (BD-I) are overweight or obese. Obesity is associated with an increased liability for mood episodes in patients with established BD-I, but data from early in the illness are lacking. Obesity in the general population is also consistently associated with functional impairment, but the relationship between weight gain and functional outcomes in BD-I has received little attention. Methods: We measured rates of clinically significant weight gain (CSWG), defined as gaining >= 7% of baseline weight, over 12 months in 46 patients with BD-I who recently recovered from their first manic episode. We compared patients with and without CSWG for (i) the amount of time spent with mood symptoms, assessed using standard clinical rating scales and National Institute of Mental Health Life Charts, and (ii) functioning at 12 months, measured using the Multidimensional Scale of Independent Functioning (MSIF). Results: A total of 41% of patients (n = 19) experienced CSWG by 12 months. We did not detect an association between CSWG and the number of days with mood symptoms. Patients with CSWG had significantly poorer 12-month global functioning than those without CSWG [MSIF score = 2.26 (SD = 1.24) versus 1.74 (0.98); p = 0.011]. Functional impairment was independent of recent or current mood symptoms, which were entered as covariates in our analyses. Conclusions: Weight gain may be an overlooked, but potentially modifiable, cause of functional impairment in BD-I. Clinicians should consider the possibility of weight gain when making the earliest treatment decisions in BD-I.