COPENHAGEN – The tantalizing prospect that statins could be repurposed as adjunctive antidepressant drugs in a defined subgroup of patients with major depression is finally about to undergo rigorous testing.
Several lines of preliminary evidence, including large observational cohort studies as well as three small, short-duration randomized trials, suggest that this might indeed be the case. It’s an extremely attractive possibility, since patients and physicians wish that antidepressant therapy were more effective, statins are among the most widely prescribed drugs worldwide, and their safety profile is thoroughly established. The expectation is that a definitive answer as to whether repurposing of statins as antidepressants is worthwhile will be provided by the SIMCODE trial, recently approved for funding by the German Federal Ministry of Education and Research,, announced at the annual congress of the European College of Neuropsychopharmacology.
SIMCODE is a multicenter, double-blind, placebo-controlled randomized trial to be conducted at eight German academic medical centers. Participants, all of whom must have major depressive disorder and comorbid obesity, will be randomized to simvastatin or placebo on top of standard antidepressant therapy with escitalopram, an SSRI which, like simvastatin, is available as a relatively inexpensive generic, explained Dr. Otte, professor and vice director of the department of psychiatry and psychotherapy at Charite University in Berlin.
For Dr. Otte, SIMCODE will close a circle he helped open with his 2012 report from the Heart and Soul Study, a prospective longitudinal study of nearly 1,000 San Francisco Bay Area patients with coronary heart disease who were assessed annually for depressive symptoms for 6 years. The 65% of patients who were on statin therapy, albeit in nonrandomized fashion, had an adjusted 38% lower risk of developing depression ().
His was one of seven observational studies involving more than 9,000 patients included in a subsequent meta-analysis showing that statin users were 37% less likely to develop depression than were nonusers ().
All agreed that the verdict isn’t in yet as to statins’ effectiveness as adjunctive antidepressants, and that the subgroup of patients with major depression who are most likely to gain added antidepressive effect from a statin are those with what the speakers variously described as comorbid cardiometabolic disease, immunometabolic disease, or simply, as in SIMCODE, obesity. These are patients with a high degree of systemic inflammation, which often makes their depression less responsive to standard antidepressant therapies. The working hypothesis is that the pleiotropic anti-inflammatory effects of statins will result in a greater response to conventional antidepressants.
Animal studies point to multiple potential mechanisms by which statins might have antidepressant efficacy in clinical practice, according to Dr. Otte. Beyond their anti-inflammatory effects, these include the drugs’ documented effects on glutamatergic N-methyl-D-aspartate (NMDA) receptors, dopamine receptors, brain-derived neurotrophic factor, glucocorticoid receptors, and hippocampal serotonin 2A receptors.