Study | Ligand | Subjects | Medication | Regions | Main finding |
---|---|---|---|---|---|
Pirker et al30 | [123I]β-CIT SPECT | 11 MDD, 1 BD, between subject design | Citalopram 20–60 mg/d; duration unclear | Hypothalamusthalamus-midbrain only 1 region | 46% occupancy* |
Meyer et al34 | [11C]DASB PET | 12MDE, within subject design | Paroxetine 20 mg/d; citalopram 20 mg/d; 4 wk tx; 6–13 h after last dose | Whole striatum; also caudate, putamen, thalamus, prefrontal cortex, insula, anterior cingulate | 80% occupancy in whole striatum and other regions |
Kent et al32 | [11C](+)McN5652 PET | 5 social phobia, within subject design | Paroxetine 20–40 mg/d; 3 to 6 mo tx | Striatum, thalamus, cingulate, hippocampus, midbrain, amygdala | Average occupancy 82% |
Suhara et al33 | [11C](+)McN5652 PET | 27 healthy; 10 patients | Fluvoxamine clomipramine healthy-acute dosing: 5 h after dose; patients: long-term dosing 1–10 h after last dose | Thalamus | 80% occupancy at clinical dose Low-dose clomipramine has considerable occupancy Acute occupancy not very different from chronic |
Meyer et al35 | [11C]DASB PET | 37 healthy; 29 MDD; 16 MDD and anxiety disorder | Citalopram 1–60 mg/d; fluoxetine1–60 mg/d; sertraline 5–200mg/d; paroxetine 5–60mg/d; venlafaxine XR 2.4–225 mg/d; 4 wk tx; 6–13 h after last dose | Striatum, thalamus, anterior cingulate, prefrontal cortex, midbrain, bilateral cuneus | 80% striatal occupancy at minimum clinical dose for SSRI; dose and plasma concentration highly predictive of 5-HTT occupancy; Regional occupancy in multiple regions correlated with striatum; significantly lower in thalamus and higher in midbrain; Striatal occupancy < 90% regardless of dose |
Erlandsson et al36 | [123I]ADAM SPECT | 16 healthy | Citalopram 10–60 mg over 2–7 d | Midbrain | Maximum occupancy 84% |
Takano et al189 | [11C]DASB PET | 15 healthy | Duloxetine 5–60 mg/d acutely (n = 12); 60 mg/d 1 wk (n = 3) | Thalamus | 80% occupancy at 40 mg single dose 84 per occupancy after 1 wk, 60mg/d half-life of brain occupancy apx. 78 h |
Takano et al48 | [11C]DASB PET | 6 healthy | Fluvoxamine 50 mg acutely | Frontal cortex, thalamus, striatum, hippocampus, amygdale | 72% occupancy 5 h postdose 50% occupancy 26 h postdose 24% occupancy 53 h postdose |
Parsey et al190 | [11C]DASB PET | 17 healthy | Sertraline 25–100 mg/d; 4 d, 24 h after last dose | 15 regions | Methods mostly dissimilar to other investigations Average occupancy 107% (large SDs) |
Herold et al169 | [123I]ADAM SPECT | 13 MDD | Citalopram 10mg/d; 1 wk, 6–7 h after last dose | Midbrain | 61% occupancy |
BD = bipolar disorder; MDD = major depressive disorder; MDE = major depressive episode; SD = standard deviation; tx = treatment.
↵* [123I]β-CIT was once the only method to image the serotonin transporter but it is probably not selective. This 5-HTT occupancy measure is believed to be a significant underestimate.