Treatment with selective serotonin reuptake inhibitors and mirtapazine results in differential brain activation by visual erotic stimuli in patients with major depressive disorder

Abstract

Objective: The objective of this study was to identify patterns of brain activation elicited by erotic visual stimuli in patients treated with either Selective Serotonin Reuptake Inhibitors (SSRIs) or mirtazipine.

Methods: Nine middle-aged men with major depressive disorder treated with an SSRI and ten middle-aged men with major depressive disorder treated with mirtazapine completed the trial. Ten subjects with no psychiatric illness were included as a control group. We conducted functional brain magnetic resonance imaging (fMRI) while a film alternatively played erotic and non-erotic contents for 14 minutes and 9 seconds.

Results: The control group showed activation in the occipitotemporal area, anterior cingulate gyrus, insula, orbitofrontal cortex, and caudate nucleus. For subjects treated with SSRIs, the intensity of activity in these regions was much lower compared to the control group. Intensity of activation in the group treated with mirtazapine was less than the control group but grea-ter than those treated with SSRIs. Using subtraction analysis, the SSRI group showed significantly lower activation than the mirtazapine group in the anterior cingulate gyrus and the caudate nucleus.

Conclusion: Our study suggests that the different rates of sexual side effects between the patients in the SSRI-treated group and the mirtazapine-treated group may be due to different effects on brain activation.

Keywords: Functional MRI; Mirtazapine; Selective Serotonin Reuptake Inhibitor; Sexual dysfunction.

FIGURE 1

A: Axial view of activated brain areas by erotic visual stimuli in healthy controls. B: Axial view of activated brain areas by erotic visual stimuli in patients with depression who treated with SSRI. SSRI: selective serotonin reuptake inhibitor. C: Axial view of activated brain areas by erotic visual stimuli in patients with depression who treated with mirtazapine.

FIGURE 2

A: Differences of activated brain regions in response to sexually explicit stimuli between control and patients with SSRI treated depression (substraction images: normal healthy control minus patients with depression who treated with SSRI). SSRI: selective serotonin reuptake inhibitor. B: Differences of activated brain regions in response to sexually explicit stimuli between normal healthy control and patients with mirtazapine treated depression (substraction images: normal healthy control minus patients with depression who treated with mirtazapine). C: Differences of activated brain regions in response to sexually explicit stimuli between patients with mirtazapine treated depression and SSRI treated depression (substraction images: patients with depression who treated with mirtazapine minus patients with depression who treated with SSRI). SSRI: selective serotonin reuptake inhibitor