Menza M, Dobkin RD, Marin H, et al. A controlled trial of antidepressants in patients with Parkinson disease and depression. Neurology. 2009;72:886-892. [PubMed]

As many as half of all patients with Parkinson’s disease (PD) suffer from depression, which leads to more rapid progression of physical symptoms, greater decline in cognitive skills, and diminished quality of life. Despite this high prevalence and considerable impact, few well-designed trials have evaluated antidepressant therapies specifically in individuals with PD. This lack of data has deprived clinicians of the opportunity to practice informed, evidence-based management of depression in this population. A recent report from the largest placebo-controlled trial conducted thus far in this setting has shed light on the relative efficacy of 2 medications: controlled-release paroxetine (a selective serotonin reuptake inhibitor [SSRI]) and nortriptyline (a second-generation tricyclic antidepressant [TCA] that inhibits the reuptake of norepinephrine and, to a lesser extent, serotonin).

Among 52 randomized patients with PD and depression, nortriptyline significantly improved scores on the Hamilton Depression Rating Scale (HAM-D) compared to placebo at 8 weeks (P<0.002) but paroxetine did not. Moreover, the rate of response (defined as a 50% improvement in the HAM-D score) was significantly superior with nortriptyline vs paroxetine (P=0.034). These findings are of particular interest in light of the fact that SSRIs are known to be the most commonly prescribed antidepressants in patients with PD. In fact, one recent analysis found that 63% of patients with PD and depression were taking SSRIs, whereas only 7% were taking TCAs.

“While preliminary, this trial yielded results that are perhaps surprising and may have significant clinical implications,” the authors commented. “While nortriptyline, given its potential for cardiac conduction delay, needs to be used cautiously, the emerging evidence suggests that its benefits are substantial.” They noted that trials of non-TCA dual reuptake inhibitors are ongoing and will hopefully provide further insights into the management of depression in PD patients.

Di Giorgio FP, Boulting GL, Bobrowicz S, et al. Human embryonic stem cell-derived motor neurons are sensitive to the toxic effect of glial cells carrying an ALS-causing mutation. Cell Stem Cell. 2008;3:637-648. [PubMed]

A great deal of interest has focused on the possibility that human embryonic stem cells (ESCs) might provide a renewable supply of differentiated cell types for use in studying specific disease processes. Such an approach would be particularly attractive for research into diseases for which the relevant cells cannot be obtained from patients (as is the case with human motor neurons). To date, however, little evidence has been available to confirm the feasibility of using human ESC-derived cells in this fashion.