[Hypothetical model of serotonin deficit in the aged subject. Development and validation of a clinical scale]

Few works exist about specific abnormalities of neurotransmission, therefore noticeable and with important clinical consequences in elderly patients. Specially serotonin, which neurotransmission is lower, seems to have a wide influence. The symptomatology of the serotonin shortage is well known in the young adult (Asberg and Van Praag). The aim of this study is to apply those hypothesis and to look for a particular clinical expression of symptoms usually related to a low level of serotonin in an older population, and this in a transnosographic way. We built up a clinical scale gathering different symptoms supposed to be related to a defect in the serotonin transmission in elderly subjects. From a first factor analysis, a dimensional scale of ten items as been settled and validated in 75 inpatients over 60 years old; each patient has also been assessed by a series of tests (MMS of Folstein, Hamilton Depression Rating Scale, Jouvent mood scale, Widlöcher Retardation Scale). Factor analysis results show an homogeneous factorial structure and highly selective items and had a three factors dispatching (a "main" factor, a "depression" factor, and "sleep" factor). Those subgroups of symptoms have a clinical meaning and fit the litterature. We also find a good specificity: the factor analysis on added items of depressive semiology (Hamilton scale) and serotonin related semiology shows the splitting of the Hamilton items, whenever the 5-HT- Scale items keep a steady factorial repartition. Those preliminary results deserve further studies; and external validation of the scale remains to be done. Nevertheless, the structure of this scale shows a beginning of internal validation and seems to be interesting in the elderly clinical evaluation.