Yeah the cognitive symptoms are horrendous, I remember thinking at one point I must have developed ADD as my ability to concentrate on tasks was so bad, constant brain fog and had trouble getting my words out while talking to people.
I actually didn't take anything when I came off the HCG. I would just stop cold turkey, I actually found my test levels would bounce back fairly quickly this way. I know this goes against everything we have been told with regards to PCT but for me personally it worked better than clomid/tamoxifen. When I would take clomid/tamoxifen after HCG my numbers where very high on the drugs (sitting around 35/36 nmol/L) however it never felt like I had test in my system and as soon as I stopped them my numbers would plummet all the way down to 9/10 nmol/L and literally take 6 months to crawl back up to baseline of around 19/21 nmol/L with good free test numbers. When coming off HCG cold turkey my numbers would bounce back to baseline in a matter of weeks, I tested this with bloodwork multiple times both with the clomid/tamoxifen and with HCG only. I watched a YouTube video by the Anabolic Doc who talks about this, he said something along the lines of that aslong as testicle Leydig cells are switched on your LH/FSH will fire up very quickly in response to external androgen levels leaving your body, the reason it doesn't work after steroid cycles is due to leydig cells shutting down when hcg is not being used and coming off cold turkey would result in relying on your own lh/fsh production trying to switch them on, which is a very slow process. If you wanted to you could use tamox/clomid as a bridge inbetween the HCG blasts, I didn't though as I'm not a fan of these drugs, I personally think they are poisonous to the body, Derek from MPMD has also talked about not being a fan of them as they are not good for the body and block a whole host of other important things your body needs.
Last night I read the reddit post/pdf that was posted on this forum about the guys theory for PSSD being a result from estrogen resistance, I think he may actually be onto something as this would explain why my high dose HCG blasts worked for me as my body would of been producing ridiculously high levels of estrogen with that HCG dose.