Mohammed T. Abou-Saleh

NOSOLOGY AND CLASSIFICATION OF MOOD DISORDERS 373illness renders it difficult to determine whether older persons dorecover from the depressive episode, which often accompanies aphysical illness within the 6 months required by the diagnosticcategory of adjustment disorder.DEPRESSED MOOD ASSOCIATED WITHDEMENTIA OF THE ALZHEIMER’S TYPE ANDVASCULAR DEMENTIADSM-IV provides for the classification of dementia of theAlzheimer’s type (both early and late onset) as ‘‘with depressedmood as well as vascular dementias’’. The frequency of co-morbiddepression and cognitive impairment renders this classification acommon one among dementia patients. As the actual pathophysiologicaland psychopathological relations between depressionand cognitive impairment are unclear, the simple recognition ofthe co-morbidity is sufficient. For example, the depression may bea reaction to cognitive decline or an actual symptom of theunderlying disease process, which also causes the cognitiveproblems. Some recent studies have suggested that a separatecategory of vascular depression be introduced. This condition ispresent when individuals meet the criteria for major depressionand have MRI-confirmed vascular brain changes. Persons withvascular depression appear to have more symptoms of apathy(perhaps due to disruption of prefrontal systems or theirmodulating pathways) and may be at increased risk of nonrecovery.CONCLUSIONIn general, the current classificatory system of both DSM-IV andICD-10 work relatively well for classifying older persons sufferingfrom mood disorders. A number of distinct exceptions must berecognized, however. Categories such as dysthymic disorder,adjustment disorder and minor depression in DSM-IV do notappear to be adequate, and therefore more exploration of theICD-10 construct of mild depression (but possibly not utilizingthe specific diagnostic criteria of ICD-10) would appear in order.A major problem with the current classification systems is theinability to take into account co-morbidity, especially co-morbiddepression and physical illness. Co-morbid depression andphysical illness is a grossly unstudied area, compared to theclinical relevance of the condition. To what extent do our currentclassification systems accommodate individuals suffering mild oreven severe depressive symptoms in the midst of physical illness?In addition, depression is often co-morbid with other psychiatricsymptoms, especially anxiety disorders and somatic complaints.Neither ICD-10 nor DSM-IV adequately accommodates the comorbidpsychiatric syndromes that are frequently seen in olderadults.Finally, when classifying mood disorders, many individualssuffer a depressed mood in late life that is not disordered.Uncomplicated bereavement is an expected accompaniment ofolder persons who experience a significant loss in old age. Inaddition, other older persons may become demoralized, given thecurrent circumstances in their lives. Such persons should not beclassified in a disease-orientated classification system. Nevertheless,these human experiences are not to be ignored by theclinician working with the older adult suffering a mood disorder.REFERENCES1. ICD-10. 1986 Draft of Chapter 5 (Categories FOO-F99). Mental,Behavioral and Developmental Disorders. Clinical Descriptions andDiagnostic Guidelines. Geneva: World Health Organization, Divisionof Mental Health, 1987 (1986 draft for field trials).2. Diagnostic and Statistical Manual of Mental Disorders, 4th edn.Washington, DC: American Psychiatric Association, 1994.3. Akiskal HS. The clinical management of affective disorders. In MichelsR, ed., Psychiatry, vol 1. Philadelphia, PA: Lippincott, 1989; chapter61.4. Dunner DL, Patrick V, Fieve RR. Rapid cycling in manic depressivepatients. Comp Psychiat 1977; 18: 561–6.5. Berman E, Wolpert EA. Intractable manic-depressive psychosis withrapid cycling in an 18 year-old woman successfully treated withelectroconvulsive therapy. J Nerv Ment Dis 1987; 175: 236–9.6. Wolpert EA, Goldberg JF, Harrow M. Rapid cycling in unipolar andbipolar affective disorders. Am J Psychiat 1990; 147: 725–8.7. Krishnan KR, Hays JC, George LK, Blazer DG. Six-month outcomesfor MRI-related vascular depression. Depression Anxiety 1998; 8:142–6.