How did mysticism change August Strindberg's later writing?

Following a period of intense mental instability and a religious crisis, August Strindberg’s embrace of mysticism—fueled by his studies in theosophy and alchemy—fundamentally transformed his creative output. This new faith re-created him as a writer, shifting his focus from the stark Naturalism of his earlier works to a more symbolic and phantasmagoric style.1

His later writing was characterized by:

• Spiritual Exploration: In works like To Damascus, he depicted himself as a wanderer seeking spiritual peace, reflecting his belief that life is governed by punitive yet righteous "Powers".1
• Expressionist Development: By moving away from stage realism, he incorporated elements such as ghosts and spirits, which helped usher in Expressionist drama.12
• Symbolic Narrative: Plays such as A Dream Play and The Ghost Sonata utilized fantastic and macabre imagery to explore themes of sin, suffering, and the hidden realities behind human appearances.12

Ultimately, this mystical turn allowed Strindberg to evolve his dramatic technique, moving beyond the brutal realism of his earlier period toward a symbolic, visionary style that significantly influenced modern European theater.1