Midbrain serotonin and striatum dopamine transporter binding in double depression: A one-year follow-up study

• Published in: Neuroscience letters 2008-08, Vol.441 (3), p.291-295
• Main Authors: Lehto, Soili M., Tolmunen, Tommi, Kuikka, Jyrki, Valkonen-Korhonen, Minna, Joensuu, Mikko, Saarinen, Pirjo I., Vanninen, Ritva, Ahola, Pasi, Tiihonen, Jari, Lehtonen, Johannes
• Format: Article
• Language: English
• Subjects: Adult; Binding, Competitive - drug effects; Biological and medical sciences; Biomarkers - analysis; Biomarkers - metabolism; Citalopram; Corpus Striatum - diagnostic imaging; Corpus Striatum - metabolism; Corpus Striatum - physiopathology; DAT; Depressive Disorder, Major - diagnostic imaging; Depressive Disorder, Major - metabolism; Depressive Disorder, Major - physiopathology; Disability Evaluation; Dopamine - metabolism; Dopamine Plasma Membrane Transport Proteins - metabolism; Double depression; Down-Regulation - physiology; Dysthymia; Dysthymic Disorder - diagnostic imaging; Dysthymic Disorder - metabolism; Dysthymic Disorder - physiopathology; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Humans; Iodine Radioisotopes; Male; Mesencephalon - diagnostic imaging; Mesencephalon - metabolism; Mesencephalon - physiopathology; Neuropsychological Tests; Positron-Emission Tomography; Predictive Value of Tests; Prognosis; Psychotherapy; Serotonin - metabolism; Serotonin Plasma Membrane Transport Proteins - metabolism; Serotonin Uptake Inhibitors; SERT; SPECT; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2008.06.042

Data on neurobiological differences between major depression (MD) and double depression (DD) are scarce. We examined the striatum dopamine (DAT) and midbrain serotonin transporter (SERT) binding of [ 123I] nor-β-CIT in DD patients ( n = 8) and compared it to that in MD patients ( n = 11) and healthy controls ( n = 19). Drug-naïve patients and controls were imaged by single-photon emission computed tomography at baseline, and the patients also after one year of psychodynamic psychotherapy. Both DD and MD groups had lower midbrain [ 123I] nor-β-CIT binding compared with the controls. Baseline 17-item Hamilton Depression Rating Scale (HAM-D-17) scores significantly decreased in both groups after one year of psychotherapy (DD: t = 3.55, p = 0.009; MD: t = 5.86, p < 0.001). No differences between the DD and MD groups were observed in age-adjusted baseline striatum or midbrain [ 123I] nor-β-CIT binding or its change during psychotherapy. Age-adjusted baseline striatum [ 123I] nor-β-CIT binding correlated inversely with the duration of both dysthymia (rho = −0.76, p = 0.03) and MD (rho = −0.83, p = 0.01) in the DD group. No such finding was observed in the MD group (rho = 0.26, p = 0.44). Baseline HAM-D-17 did not correlate with the change in striatum or midbrain [ 123I] nor-β-CIT binding in either group. In conclusion, our findings suggest that when using midbrain [ 123I] nor-β-CIT binding as a marker of SERT binding, no differences are detectable between patients with DD and MD. However, low striatum [ 123I] nor-β-CIT binding, a marker of DAT binding, may be associated with a longer illness duration in dysthymia.