Mohammed T. Abou-Saleh

404 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYof the serotonin system showed a number of interestingassociations. A SPECT study of the brain serotonin transportreceptor reported reduced density in depression 17 , whilst a PETstudy of the serotonin type 2 receptor function showed a decreasein receptor density following treatment with desipramine,particularly in the frontal region 18 . Studies of the 5-HT 1A systemshowed a reduction in receptor density in the mesiotemporalcortex in bipolar patients, and in unipolar patients with bipolarrelatives 19 and an association between widespread reduction of5-HT 1A receptor binding and depression in medicated and nonmedicateddepressed patients 20 . Finally, studies of MRS depictingbiochemical changes have detected an association betweendepression and reduced glutamine and glutamate, using proton-MRS 21 , and increased phosphomonoesters and decreased ATPvalues in the frontal lobes of patients with major depression using31 P-MRS 22 .In summary, the findings of neuro-imaging studies in depressionadd credence and support to the biological basis ofdepression, refine its diagnostic subgroups and inform itstreatment with more specific pharmacological treatments.REFERENCES1. Videbech P. MRI findings in patients with affective disorder: a metaanalysis.Acta Psychiat Scand 1997; 96: 157–68.2. Krishnan KRR, McDonald WM, Escalona PR et al. Magneticresonance imaging of the caudate nuclei in depression. Arch GenPsychiat 1992; 49: 553–7.3. Drevets WC, Price JL, Simpson JR Jr et al. Subgenual prefrontalcortex abnormalities in mood disorders. Nature 1997; 386: 824–7.4. O’Brien JT, Desmond P, Ames D et al. A magnetic resonance imagingstudy of white matter lesions in depression and Alzheimer’s disease. BrJ Psychiat 1996; 168: 477–85.5. O’Brien JT, Chiu E, Schweitzer I et al. Severe deep white matter lesionson MRI brain scan predict poor outcome in elderly patients with majordepressive disorder. Br Med J 1998; 317: 982–4.6. De Groot JC, de Leeuw FE, Oudkerk M et al. Cerebral white matterlesions and depressive symptoms in elderly adults. Arch Gen Psychiat2000; 57: 1071–6.7. Soares JC, Mann JJ. The functional neuroanatomy of mood disorders.J Psychiat Res 1997; 31(4): 393–432.8. Hickie I, Ward P, Scott E et al. Neo-striatal rCBF correlates ofpsychomotor slowing in patients with major depression. Psychiat Res1999; 92: 75–81.9. Galynker II et al. Hypofrontality and negative symptoms in majordepressive disorder. J Nucl Med 1998; 39: 608–12.10. Upadhyaya AK, Abou-Saleh MT, Wilson K et al. A study ofdepression in old age using single photon emission computerisedtomography. Br J Psychiat 1990; 9: 76–81.11. Sackeim HA, Prohovnik I, Moeller JR et al. Regional cerebral bloodflow in mood disorders. 1. Comparison of major depressives andnormal controls at rest. Arch Gen Psychiat 1990; 47: 60–70.12. Baxter LR Jr., Schwartz JM, Phelps ME et al. Reduction ofprefrontal cortex glucose metabolism common to three types ofdepression. Arch Gen Psychiat 1989; 46: 243–50.13. Abou-Saleh MT, Al Suhaili AR, Karin L et al. Single photonemission tomography with 99m Tc-HMPAO in Arab patients withdepression. J Affect Disord 1999; 55: 115–23.14. Shah PJ, Ogilvie AD, Goodwin GM et al. Clinical and psychometriccorrelates of dopamine-D2 binding in depression. Psychol Med 1997;27: 1247–56.15. Larisch R, Klimke A, Vosberg H et al. In vivo evidence for theinvolvement of dopamine-D2 receptors in striatum and anteriorcingulate gyrus in major depression. Neuroimaging 1997; 5: 251–60.16. Laasonen-Balk T, Kuikka J, Viinamaki H et al. Striatal dopaminetransporter density in major depression. Psychopharmacology (Berl)1999; 144: 282–5.17. Malison RT, Price LH, Berman R et al. Reduced brain serotonintransporter availability in major depression as measured by [123I]-2b-carbomethoxy-3 b-(4-iodophenyl) tropane and single photonemission computed tomography. Biol Psychiat 1998; 44: 1090–8.18. Yatham LN, Liddle PF, Dennie J et al. Decrease in brain serotonin 2receptor binding in patients with major depression followingdesipramine treatment: a positron emission tomography study withfluorine-18-labeled setoperone. Arch Gen Psychiat 1999; 56: 705–11.19. Drevets WC, Frank E, Price JC et al. PET imaging of serotonin 1Areceptor binding in depression. Biol Psychiat 1999; 46: 1375–87.20. Sargent PA, Kjaer KH, Bench CJ et al. Brain serotonin 1A receptorbinding measured by positron emission tomography with [11C]WAY-100635: effects of depression and antidepressant treatment. Arch GenPsychiat 2000; 57: 174–80.21. Auer DP, Putz B, Kraft E et al. Reduced glutamate in the anteriorcingulate cortex in depression: an in vivo proton magnetic resonancespectroscopy study. Biol Psychiat 2000; 15: 305–13.22. Volz HP, Rzanny R, Riehemann S et al. 31 P magnetic resonancespectroscopy in the frontal lobe of major depressed patients. Eur ArchPsychiat Clin Neurosci 1998; 248: 289–95.Is Imaging Justified in the Investigation of Older People?D. McWilliamRibbleton Hospital, Preston, UKDementia is still diagnosable only by clinical examination, but afurther battery of diagnostic tests may then be required to clarifythe aetiology and identify potentially treatable cases. Anyassessment of the cost-effectiveness of these further tests,including neuro-imaging, must compare the relative value ofroutine testing in all patients against selective testing in caseswhere there is a high index of suspicion or diagnostic doubt.Routine testing will detect the small number of patients (about1%) with a reversible cause for their dementia, but is burdensome,especially in the elderly, and may raise false expectations and leadto false-positive results. It would also identify early cases suitablefor drug therapy. Selective testing will result in some treatablecases being missed, but causes less general risk and discomfort andmay be more cost-effective, especially in those countries whereneuro-imaging remains expensive and difficult, or even impossible,to access 1,2 .Providing cost-effective and accurate diagnosis of dementiatherefore presents the clinician with a dilemma. Can neuroimagingbe included in a battery of ancillary investigations devisedfor routine use in all cases of dementia, or need such tests becarried out only as clinically indicated? The fact that definitivedata on the sensitivity, specificity and cost-effectiveness of various