No, not much study was "permitted" by mainstream academia, and what little was published of course went with globohomo orthodoxy that it's all horrible and evil. Attempting to study it today from a "neutral" or even "hey maybe it does work" position gets you tossed out of academia and branded a "homophobe" for life.
Effective gay conversion therapy exists, and it's practically no different from traditional (and recognized) abuse therapy techniques -- it just focuses on a different kind of trauma. As it happens, practically all homosexually ultimately stems from early-life sexual abuse by a same-sex abuser. Gay people are made, not born. As it turns out, conversion therapy doesn't beat people over the head with bibles and encourage them to "pray the gay away." It provides legitimate therapy to help abuse victims identify and come to terms with their abuse, explore why they behave the way they do because of it, examine how their current behaviors put them at greater risk for an assortment of "poor outcomes," and finally figure out what they actually want for themselves (not just what the "queer community" cult surrounding them wants).
In other words, people turn gay because Uncle Bob touched them when they were young and it fucked up their idea of sexuality. Then hormones kick in, and the gay community -- always in search of fresh meat -- is all too happy to provide the young all the sexual debauchery they could ever ask for. "Conversion" therapy is really just "sexual trauma" therapy, with the uncomfortable conclusion that "you're likely straight, just fucked up because Uncle Bob touched you when you were younger and his friends then took turns railing your virgin ass repeatedly during your teenage years."