I mean, depends how far back into the dark ages you want to go. The Frankfurt school used state of the art psychology at the time, the beautiful, the accurate: Fruedianism
In the 60s, the developmental Psychologist Erik Erikson was friends with Huey Newton
More recently? IDK, I'm a humanities major
Zizek is essentially a Lacanian psychologicist who knows enough other shit to do a philosophy. Otherwise Lacan is pretty interesting.
Zizek's published critiques of broader psychology, though alas it's been so long I don't remember the works offhand
Adding to this, while this article isn't written by Zizek, I think he would agree with this critique of ego psychology https://www.lacanonline.com/2010/10/what-does-psychoanalysis-have-to-do-with-psychology/
You've probably already heard of Industrial-Organizational psychology. Although it's a field that's more about shit like productivity and helping to further benefit employers, I think there's potential there to promote leftist policies like worker co-ops, workplace democracy, less work hours, and more.
Here are some articles:
NephewAlphaBravo has a great recommendation with It's Not Just in Your Head. Both hosts are therapists and leftists, one is in their thirties and the other has been an activist since the 60s.
Episode 30: Are DSM-5 Mental Disorders A Construct Of Capitalism?
Great episode to start with. They mention authors frequently and often have very cool guests like the recent episode 50 where they interview Dr. Lucy Johnstone, one of the lead authors of the Power Threat Meaning Framework (PTMF), which is intended as a replacement to the DSM that acknowledges the ill effects of neoliberalism and how they directly impact mental health.
You could actually straight up message them about this on their website, they say they respond to everything people send them.
Only thing I know of offhand is this , maybe you'll find a rabbit hole from there
I always recommend Wilhelm Reich's The Mass Psychology of Fascism.
Two great podcasts, Red Library and The Regrettable Century, deal a lot with the conjunction of Marxism and psychology. Now that I think about it, there's also Machinic Unconscious Happy Hour and Why Theory.
Based on this article I'd say it's worth checking out Carl Ratner
Oddly enough I came across a book recently that you may be interested in. I was going to give you a libgen link for it, but apparently it's down at the moment. Luckily the Internet Archive has a copy of it here. It's called Mind and Tissue: Russian Research Perspectives on the Human Brain - it's about psychology research conducted by the Soviets.
The author really puts it out there in his preface as well:
If the Cold War in science is to end, I think we must achieve clarity and self-consciousness by impugning the scientists who have built their careers on loyalty oaths and silence in the face of McCarthyism or other forms of censorship, mind-control, or fascism. We should remember that hundreds of German scientists who condoned "racial hygiene" and murder-experiments are still contributing to the atmosphere of the scientific community.