Hello Kiseki Thanks for your question First of all I would like to advise you to check clinically that whether you are having hypothyroidism, as it is a very common co-morbid condition with depression. Check if you are having intolerance to cold, dry skin, decreased sweating, poor appetite, weight gain, oligomenorrhea etc. Secondly you can visit any good lab and get you Thyroid Function Tests done (T3/T4/TSH) Usually in hypothyroidism in early stages TSH levels are in higher range and T3/T4 levels either normal or decreased. Secondly get your Vitamin B12 and Folate levels checked as low Vit b12 ( Vitamin D levels of yours are presently in normal range so you need not to worry. So as per my advise continue taking good antidepressant line Sertaline for long to increase the period of normality in between episodes. Thyrodi supplementation like Eltroxin in lower doses always improve symptomatology. Vit B complex capsules are also very beneficial. So first of all ask you attending doctor for reports of your thyroid and Vitamin B12 levels and then you can ask him to modify or add new medicines. Thanks hope I cleared your doubt kindly rate