Serotonin transporter binding is reduced in seasonal affective disorder following light therapy

    loading  Checking for direct PDF access through Ovid



To investigate the effects of light therapy on serotonin transporter binding (5-HTT BPND), an index of 5-HTT levels, in the anterior cingulate and prefrontal cortices (ACC and PFC) during winter in seasonal affective disorder (SAD). 5-HTT BPND fluctuates seasonally to a greater extent in SAD relative to health. We hypothesized that in SAD, 5-HTT BPND would be reduced in the ACC and PFC following light therapy.


Eleven SAD participants underwent [11C] DASB positron emission tomography (PET) scans to measure 5-HTT BPND before and after 2 weeks of daily morning light therapy.


The primary finding was a main effect of treatment on 5-HTT BPND in the ACC and PFC (repeated-measures MANOVA, F(2,9) = 6.82, P = 0.016). This effect was significant in the ACC (F(1,10) = 15.11 and P = 0.003, magnitude of decrease, 11.94%) and PFC (F(1,10) = 8.33, P = 0.016, magnitude of decrease, 9.13%). 5-HTT BPND also decreased in other regions assayed following light therapy (repeated-measures MANOVA, F(4,7) = 8.54, P = 0.028) including the hippocampus, ventral striatum, dorsal putamen, thalamus and midbrain (F(1,10) = 8.02–36.94, P < 0.0001–0.018; magnitude −8.83% to −16.74%).


These results demonstrate that light therapy reaches an important therapeutic target in the treatment of SAD and provide a basis for improvement of this treatment via application of [11C]DASB PET.

Related Topics

    loading  Loading Related Articles