[Frontal lobe dysfunction and depressive state: relation to endogenous character of depression]

A dysfunction of dorsolateral prefrontal cortex (DLPF) in major depression is suggested by functional imagery and comparative neuropsychology. However, assessment of frontal lobe syndrome with DLPF-dependent tests led to controversial results. To clarify these findings, we administered 5 of these tests (Wisconsin Card Sorting Test, Stroop Test, Trail Making Test, Tower of Toronto, verbal fluency) to 16 major depressive subjects and their 16 controls, before and after 21 days of treatment. Furthermore, we tried to assess the prognostic value of frontal lobe dysfunction, and its relation with the endogenous or exogenous nature of the depression on the one hand, the severity of the depression on the other hand. Our results suggest that the presence of a frontal lobe syndrome (defined by impaired performances at 3 tests or more) is only noted in endogenous depression; after treatment, no impairment is detected. No correlation is found with the severity of the depression. Frontal lobe syndrome does not seem to indicate poorer prognosis for current depressive episode.