[Imitation and utilization behavior in major depressive states].

Imitation and utilization behaviour (IB ; UB) have been described in lesions or deafferentations of the frontal lobes. Both reflect a loss of the patients' autonomy. IB and UB having been encountered in a case of melancholia, a systematic study has been undertaken in psychiatric departments. Sixty patients have been examined among whom 18 had a major depressive episode and 19 a dysthymic episode. IB or UB or both were present in every case of the first group, in 3 cases of the second one. Such data show first an unexpected focal specific neurological sign in a psychiatric disease. Second, they suggest a relationship with the frontal hypoactivity shown by PET studies in major depressive episodes. Such frontal hypoactivity should not be viewed as the cause of major depression but as a concomitant disorder. Its role in the awareness and expression of the thymic disturbance is discussed.