I read a book by a famous psychiatrist who interviewed dozens of doctors doing cutting edge research into the field for the treatment of various conditions. Mostly nuero-motor conditions but essentially they all proved that brain cells can regrow and also adapt to changing neurological conditions. The didn’t go much into depression but he did discuss how they had shown that during some depression treatments they believed it wasn’t actual meds that made patients recover but by induced brain cell regrowth that helped them recover.
It struck me immediately; since we don’t seem to see much resolution for other side effects, but the brain being vital to our survival must adapt into its new environment to function. Even years later we all have low neurosteroids, but our brain cells (especially the newer ones) may be more sensitive to the neurosteroids we do still have. Most likely with a higher number of receptors for the neurosteroids.
Found the link, here is the book in-case your interested: