Earlier quoted context omitted.
Again, the author cited him as "the psychiatrist Scott Alexander". If he did verify credentials, he ought to have mentioned the name is an alias.
He could have mentioned it, but I don't understand why you think it's important? The authors of the actual scientific study are Richard Border and his co-authors. Scott Alexander is just a well-known blogger who gets credit for writing about it in a vivid way that got people's attention. He's not a primary source, so for the purposes of this article, it doesn't really matter whether he's using an alias or even whethe…
Scott Alexander is a pseudoynm. Journalists referencing that name should note this, along with the fact that his credentials as a psychiatrist are not publicly verifiable.