Assessment of depression in multiple sclerosis: development of a "trunk and branch" model.

The objective of the present investigation was to improve the detection of depression in multiple sclerosis (MS). It has been hypothesized that the overlap of MS symptomatology and neurovegetative depression symptoms may lead to an over-diagnosis of depression in MS. Discerning what is depression and what is more attributable to the disease renders a complicated picture when assessing depression in medically ill people. Given this, "trunk and branch" models have been proposed. In such models "trunk" symptoms are purported to be the symptoms common to the medical condition and less likely reflective of depression. "Branch" items are those symptoms that are independent of the medical condition and likely reflect depression. In the present investigation we compared depressed individuals with MS, non-depressed individuals with MS, and non-depressed controls, to devise a "trunk and branch" model for use with individuals with MS. By identifying which symptoms are typical in MS, which exceed what is typical in MS, and which symptoms are independent of MS, but more often present in depressed individuals with MS, we hoped to present a better understanding of the nature of depression in MS.