Please pause a moment to collect your own thoughts on how it happened.
If you had asked me, I would have said that Gustavus W. Smith suffered some sort of breakdown and Davis then assigned Lee to take over from Smith (who had taken over from Johnston). Was that your recollection too?
I never looked deeply into this. The record gets very thin when addressing what the malady was and how it was manifested. It is most odd for our beloved storytellers to pass up juicy gossip or vivid anecdotes in constructing their tales.
I gave one formulation of the legend but there are variations. Consider these:
Wiki: ... he suffered what was likely a nervous breakdown upon taking command and Jefferson Davis replaced him with Robert E. Lee the following day, June 1."
Comment: Wiki speculates about nervous breakdown ("likely") and gives the malady date as May 31 (working backward from June 1, the "following day"). It presents in one sentence, breakdown > replacement. It does not source the breakdown.
In The Civil War: a History, Harry Hansen, Gary Gallagher, and Richard S. Wheeler take a crack at it: "... command devolved on Major General G.W. Smith. But Smith, who was near a nervous breakdown, made a poor start ... On this Sunday morning, June 1 ... At noon President Davis appointed General Robert E. Lee to the command of Johnston's army."
Comment: At noon on June 1, 1862, Davis appointed Lee to the command; this is quite a distinction from Lee taking command subsequent to an appointment. Please note it. This follows "a poor start" by Smith with the reader invited to draw a causal inference. Smith is "near a nervous breakdown," something the reader cannot picture without help, and no details are given.
Now The Seven Days by Cliff Dowdey: "When on June 1 the army devolved on Gustavus Smith ... [he] suffered a total collapse of his faculties. Smith was removed from the field in a state he called paralysis, and which today would probably be diagnosed as traumatic shock."
Comment: Note Dowdey makes the odd point that the army did not devolve on him on May 31, when Johnston left the field wounded, but the next day. Note also the sequence: assumes command on the 1st, suffers immediate collapse.
Let's work backwards from Dowdey, for despite the lack of notes, he gives Smith as his source and in his bibliography he has only one of Smith's books, the Battle of Seven Pines. So Smith is his source.
I have not yet found any other source on the malady aside from Smith himself. If you have one please advise.
Here is what Smith says in his Century article, "Two Days of Battle at Seven Pines":
I was completely prostrated on the 2nd of June by an attack of paralysis, no symptom of which was manifested within eighteen hours after Lee relieved me of command of the Army.Smith is stricken on June 2nd! He uses a specific word in two sources: paralysis. No nervous breakdown, no "collapse of faculties" or "trauma." If Smith is the sole source on this, the judicious historian cannot swap out the word paralysis for another of his own choosing. He has recovered by the night of the 2nd (within eighteen hours after Lee assumed command).
Elsewhere, Smith wrote that Lee was promised command of the army by Davis the night of the 31st when Johnston was wounded. This separates Smith's performance and health from the command decision. It also separates the appointment to command from the assumption of command.
These are matters that should interest the Civil War historian but apparently do not.
Moreover, in the Century piece Smith quotes a letter from Lee approving of Smith's own attack plans for June 1st. In the afternoon of the 1st, after the change of command, he says Lee gave him no orders. Smith directed the fight all day. Smith's postwar writings detail how he fought Seven Pines on June 1 and refute Longstreet's and Johnston's criticism of his conduct of the battle on June 1.
Smith (1) fought the battle and then (2) suffered "paralysis." If Smith is the sole source of our knowledge of the affliction, that has to be the sequence.
Meanwhile, have some medical fun:
Paralysis: "A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function."
Nervous breakdown: "...a popular term - it is not a clinical term - that is often used to describe a mental disorder that a person experiences. It is used for a number of reasons, including: to hide a diagnosis; to avoid the stigma of a diagnosis; not understanding the reasons for certain loss of function..."
So "nervous breakdown" takes us away from the specific - "paralysis" - to the nonspecific. It interjects ambiguity into the record where there was specificity.
Psychological trauma/shock: "Psychological shock can occur after a physically or emotionally traumatic experience but it effects [sic] your state of mind (although this can give you symptoms such as palpitations and feeling faint, it doesn’t usually lead to serious physical collapse)."
The matter of the "madness" of G.W. Smith is again one of many signs of the quality of love our ACW writers have for their readers.