Is there any psychological journal that is written in Esperanto?

My guess: no.

If anyone would have written articles in an Esperanto psychological journal, that would have been the late Claude Piron, who lectured in psychology, and who also wrote a psychoanalysis of people’s attitude to international languages. (No, I’m not endorsing that kind of thing.)

I’ve looked through his now defunct fan page at Pironejo , Claude Piron: Bibliografio . Not seeing any evidence he published in anything such.

I’m not sure there have been academic journals in Esperanto about anything other than Esperanto (including Esperantologio and Planlingvistiko, which were pretty good).