The study involves an experimental medicine trial carried out with healthy volunteers. It mirrors a previous trial undertaken with a similar group of participants. Both trials have investigated medications that are widely used to treat heart diseases, by lowering cholesterol and inflammation in the blood, atorvastatin and simvastatin. Whereas atorvastatin was linked to perceiving emotions as more negative, in contrast, simvastatin led to perceiving emotions as more positive. However, simvastatin was also seen to slightly increase subjective anxiety scores, perhaps mimicking what happens with commonly used antidepressants: an initial worsening of anxiety, later followed by an improvement in depressive and anxious symptoms.
Taken together, these findings suggest the possibility that atorvastatin might worsen depression and anxiety, while simvastatin might improve symptoms of depression, although at the expense of some increase in anxiety at the beginning of treatment.
Atorvastatin, used in the previous trial, is a highly potent statin that can reach the brain. Giving atorvastatin for seven days to healthy volunteers was associated with worse emotional perceptions, linked to later development of depressive and anxiety symptoms.
Simvastatin, used in the current trial, is a less strong statin, but it is also capable of entering the brain. Giving simvastatin for seven days to healthy volunteers was associated with a small improvement of emotional perceptions, which could in time lead to a reduction of depressive symptoms.
Dr Riccardo De Giorgi, study author and Wellcome Trust Doctoral Training Fellow, University of Oxford, said:
'Our findings are intriguing because they show that two similar medications, generally used to treat heart conditions, can not only affect the brain, but also do so in opposite ways. This provides some important insights about the effects of statins on common mental disorders, such as depression and anxiety. The ability of statins to reduce excessive inflammation could eventually lead to the development of better treatments. Further clinical studies, especially in patients currently suffering from depressive illness, are needed.'
Read the full study, An experimental medicine study of the effects of simvastatin on emotional processing, reward learning, verbal memory, and inflammation in health volunteers, published in Psychopharmacology.