[Alexithymia, depression and drug addiction].

Alexithymia is a multidimensional concept associating an emotional component focused on the difficulty in identifying and describing feelings and a cognitive one centred on the use of a concrete and poorly introspective way of thinking. Alexithymia can be assessed by self-assessment instruments and in particular by the 20 items version of the Toronto Alexithymia Scale (TAS-20). Depressive disorders have complex relationships with the construct of alexithymia and there exist few experimental works on the subject. Epidemiological studies frequently raise an overlap between alexithymia and depression, in particular in the context of addiction. The main aim of this study was to confirm the high prevalence of alexithymia among drug addicted patients taking into account socio-demographic variables (sex, age, social and economic categories). The second aim of the study was to investigate the relationships between alexithymia and depression among drug addicted patients. A sample of 128 drug addicted patients answering DSM IV criteria of dependence to a psycho-active substance (alcohol excluded) was paired according to socio-demographic variables to a control sample of 128 normal subjects. Diagnostic assessment was made using the Mini International Neuropsychiatric Interview (MINI). Alexithymia and depression were assessed with the TAS-20 and with the short version of the Beck Depression Inventory (BDI-13). The results confirm the high prevalence of alexithymia among drug addicted patients (43.5%) compared to controls (24.6%). This difference is based namely on the emotional component of alexithymia, the cognitive component failing to show any difference between the two samples. Moreover, alexithymia appears to be independent from socio-demographic variables in our sample of drug addicted patients; 66.4% of drug addicted patients presents a depressive symptomatology (which is significantly more important in female patients), compared to 26% of the controls. Studies using the TAS and the BDI with 21 items have shown that from 10 to 20% of the variance of alexithymia is explained by depression. Our own results show a shared variance of 20% between the TAS-20 and the BDI, going in the direction of a moderated correlation between alexithymia and depressive symptomatology. Moreover, when we retain only subjects without depressive symptomatology at BDI, drug addicted (n=42) are not any more alexithymic than controls (n=114). Our results plead for a positive association between depression and alexithymia in drug addicted, depressed or healthy subjects. Alexithymia and depression would be two associated dimensions, the emotional component explaining alone this association. The emotional component of the alexithymia would be thymo-dependent, whereas the cognitive component (externally oriented thought) would be independent and constitute a stable clinical feature. These results are concordant with other studies in the literature suggesting that alexithymia in its emotional component is supported by depression. Alexithymia thus did not appear as an autonomous dimension which would discriminate between drug addicted and controls, independently of the absence of a depressive state. The Authors discuss the complexity of the relationships between alexithymia and depression and the correlations between TAS and BDI scales especially for the factor Difficulty Identifying Feelings. These results deserve further studies. The cross-sectional nature of this study do not allow to establish if alexithymia is a subjacent and preexistent in the form of a psychopathological dimension in addictive behaviours, so supporting its emergence, and/or if it develops once the dependence is installed and chronicized. Longitudinal studies remain to be realised.