I've always interpreted Marx's concepts of alienation as talking about mental health issues. More recently people have definitely began to link the material conditions of capitalism with mental health issues, although a specifically Marxist writing on the topic doesn't spring to mind right now. It's also clear to me, both from lived experience as well as various things I've read, that dealing with this alienation labour is almost entirely the same as dealing with common mental health issues such as depression/anxiety, loneliness, and the existential question of what the purpose of my life is.

capitalist alienation is a significant cause/worsener of mental health issues, and he certainly did write about that (although the Solution is Revolution(TM) so there's no individual solution there)

Since very good answers already been done I just go with an anecdote from a therapist. Therapy is good but money really makes a difference..