Question: I am a 28 year old male, otherwise in good health. About 7 months ago I was prescribed clindamycin for a skin infection, since then I have developed IBS. I got tested for cdiff twice (4 samples in all) and it was negative each time. To deal with the IBS, I have started probiotics which have helped. About two months back, I took a multi-strain probiotic for about two weeks, it contained ( L. rhamnosus, L. helveticus, Bifidobacteria Longum, L. Casei, L. Plantarum, Lactococcus Lactis, B. Breve, Pediococcus acidilactici, 5Billion CFU in all). Since then I have been occasionally experiencing what can be described as brain fog. I also feel a slight heaviness at the top of my head and a slight fatigue. It makes it difficult to concentrate on mentally challenging work, but not to the point where I am forgetting stuff. Also, when the fog is strong I get a slight feeling derealization and depersonalization. Also it seems to be present some days or some times of the day. It tends to be more severe on days when I have slept less. I stopped the probiotic about six weeks ago but the condition persists. I have had a CBC and thyroid (T4 and TSH) testing done in relation to the IBS about a month back and that was completely normal. Since this started after taking the probiotic and some people have mentioned such side effects from probiotics, I am quite sure that this is due to the probiotic. My GI symptoms have improved considerably since then and I would say that I am close to normal as far as GI problems are concerned, however I have been left with this brain fog. My GI doctor referred me to a neurologist whom I will visit next week. Currently, I have increased my sleep and rest and started meditation, to reduce stress or anxiety and I am planning to start fish oil capsules and a multi-vitamin. Please advise.

Thanks for your reply. My IBS was caused due to antibotics killing the good bacteria and not due to anxiety and my symptoms have greatly reduced over the last two months and I would say that I am 90% cured of it. During my IBS, I was under stress and anxiety and worrying whether I had Crohn's disease etc. but all those worries have greatly reduced as my IBS symptoms have significantly improved and hence I am a bit sceptical of the anxiety diagnosis.

I have also taken steps to reduce anxiety/stress by sleep/rest, exercise and yoga, though it is early to tell if there is an improvement. However, I find it hard to believe that the brain fog and fatigue is being caused by anxiety alone, especially when my IBS related worries have greatly reduced. Also while I had stress/anxiety, I never had any panic attacks. While anxiety might be exacerbating the problem, I thing there is some other underlying cause.