I'm not the other "unregistered" poster, and I doubt that she'll be back given the savage and unwarranted attacks on her comments.
Lithium and newer drugs are often used for mild mood swings that are more associated with transitional anxiety and depression than major psychosis. Federal guidelines allow lithium with appropriate Dr's recommendations for commercial truck and bus licenses, by the way.
Only a qualified physician with an active patient relationship can determine whether auto, large truck or recreational aviation was a safe activity, and the possibility of psychosis if the meds weren't taken (i.e. worst case) would be a factor. Given that a primary reason that pilots don't take meds or seek care is to avoid draconian, illogical FAA medical mandates it's reasonable to believe that mildly medicated pilots with mood swings would perform better than those who ignore or try to hide medical conditions from the FAA, which I'd estimate to be 100% of pilots of 40 at one time or another.
Keep in mind that all psychiatric conditions are "normal"---in some individuals and in some circumstances the behaviors exceed the norm, and often can be treated like any other type of disease. The ability of AMEs and FAA bureaucrats to make complex medical decisions about patients they have no relationship with is laughable, and sets up a conflict relationship that's contrary to flight safety.
I wouldn't ride with a pilot (other than a safety pilot) who couldn't see, or was suffering from dementia, or who had serious heart problems. I have no reservations about ATPs who have treatable psychological conditions---it's a fair assumption that most pilots who suffer pschotic breaks, fly into the IRS, etc. are those eligible for medicals because they don't (and are discouraged from) seeking appropriate treatment.
FAA employees and MDs are caught regularly falsifying their medical conditions, and if they believe that some of the restrictions are BS why wouldn't we? The referral to GP and chemist opinions in this string are false representations of authority, if/when non-FAA psychiatrists start posting up I'll listen more closely to their opinions.
Until then, the FAA's position that recreational pilots prove a negative (i.e. that they're not a menace to the skies) with no reasonable opportunity offered to do so (like, say, a flight or series of flights with a Dr and check pilot) makes as much sense and is as ignorant and mean-spirited as locking up young minority males because stats say they could be a greater-than-average danger, and there's no way for them to prove the null. History warns us that any approach that deals with people in non-individual ways is an invitation to bureaucratic abuse and draconian enforcement.
In closing, I find it embarrassing to the entire aviation community that the Dept of Commerce is far more forward-looking and intelligent about managing the medical issues of 80,000lb semi-drivers than the FAA. I don't know if the relative absence of medical-related accidents in Sport Pilot is due to pilots getting needed treatments and choosing not to fly when their personal physicians advise them not to, but it's a reasonable theory.