Background: Late-onset depression (after age 60) has more frequently been reported to be associated with brain abnormalities compared to early-onset depression. Consistent with the hypothesized role of frontolimbic circuits in the etiology of depression, the preponderance of cross-sectional studies of late-life clinical depression have revealed structural and functional changes in the frontal lobes.
Case report: NK was 70 years old female patient. She had a psychiatric history of five years with these symptoms. She had used several different antidepressants and benzodiazepines at adequate doses and some times low-dose atypical antipsychotics but she never had a full recovery. In this hospitalization, she was diagnosed as Major Depressive Disorder according to SCID-I. In MRI, we found generalized cortical atrophy especially in the frontal region. In neurocognitive tests, we realized that her minimental test score was 25. Wisconsin Card Sorting Test and Stroop test (main card reading time 54 seconds) showed disability in the executive functions such as cognitive flexibility, planning, decision making, overcoming of a strong habitual response or resisting temptation and in focused attention and working memory. The other cognitive domains evaluated with Rey Auditory learning test, Auditory trigram test, digit span test, trial making test, word association test were found to be normal.

Conclusion: Treatment-resistant depression (TRD) is usually conceptualized as a failure to respond to several courses of adequate antidepressant treatment. Our findings can be suggested that cortical atrophy in especially frontal lobes can be consistent with a treatment resistance and neurocognitive impairment.