Assessing suicide ideation in patients with traumatic brain injury (TBI) by using depression scales.

I IS with great interest that we read the special issue on “Perspectives on Suicide and Traumatic Brain Injury” and we particularly appreciated the paper by Tsaousides et al. entitled “Suicidal ideation following traumatic brain injury: prevalence rates and correlates in adults living in the community.”1 In this paper, the authors explored the rates of suicidal ideation (SI) in a cohort of 356 community-dwelling adults with mild to severe TBI. One particular issue raises discussion. To date, three of the key studies investigating SI following TBI have made use of items from the Beck Depression Inventory (BDI-II,2),1,3,4 while only one group has used Beck’s Scale for Suicide Ideation (SSI5).5–7 Investigating SI by BDI-II was proposed by Wenzel, Brown and Beck,8(p.29) but was never validated. Fortunately, we recently validated this approach in a cohort of 281 suicide attempters aged between 18 and 83 years without any neurological condition.9 We (1) extracted the score of the sole “suicide” item from the BDI and from the Hamilton Depression Rating Scale (HAM-D) and, (2) using principal component analysis, we extracted several orthogonal components across the 17 items from the HAM-D. The second component, accounting for 7.36% of total HAM-D variance, loaded mainly for the “suicide” item. We then correlated these measures to the gold standard SSI. These findings suggest that the use of a single “suicide” item or a dimensional factor (i.e. the second orthogonal component) derived from a depression scale might be a valid approach to assess suicidal ideation. Moreover, results suggest that clinician-rated scales as well as self-report questionnaires are equally valid to do so. Of course, a limitation remains that an evaluation of SI by a single item derived from depression scales