I sincerely don’t think our discussion are really useful for the guy that has started the conversation, but just to clarify: if you are referring about brain serotonin levels, the relation is not so clear, and a lot of the time (depending on the methods used in the study) it can be mediated by conversion to estradiol. The only thing of we can be sure, is that estrogen increase serotonin levels and serotonin 5-ht2a. Studies of pure androgens on brain chemistry are less clear, mixed and sometimes contradictory, they suggested a more responsive serotonin system by upregulating some type of receptors (like 5-ht1a) or the response to releasing agents, increasing synthesis and degradation. But the net result is another story, given the effect on other neurotransmitters with opposing effects. Here the effects of testosterone (without manipulation on the natural aromatization) is well predictable, and translate in an opposing effect between testosterone and serotonin. You can read some references here, but there are a lot more
Moreover, it doesn’t require to cite these studies to know the opposing effects of testosterone and serotonin: I fly over the pro-anxiety and pro-depressive effect of having high serotonin levels via SERT dysfunction, given that it is a too big argument to treat in a discussion like this, but all the other effects of high serotonin, like low sexual drive and low impulsivity, are clearly the opposite of those of testosterone.
Regarding aerobic training, the argument seems a nonsense for me: I imagine that he even drinks water daily, and the fact the this has not helped with his condition, does not mean that he should stop drinking water. A little aerobic is a must for all people, especially for depressed ones or for people that like him need to have healthy balanced routines.
Same for coffee: what are you talking about with this attempt at irony? He has clearly stated having a huge problem with insomnia, that in itself brings a lot of trouble: how can you recommend drinking more coffee, only for an alleged lack of catecholamines which, if so, should be treated differently?
I too often find myself at odds with the dominant thinking, and I appreciate this side of your arguments, but try to be cautious in suggestions







