Eli Lilly said it will acquire clinical-stage drug developer AtaiBeckley in a deal valued at up to $3.8 billion, signaling a major move deeper into neuroscience and mental health treatment research. The transaction reflects Lilly’s growing interest in therapies aimed at depression and other psychiatric conditions.

Investors reacted quickly to the announcement, with AtaiBeckley shares surging about 30% in pre-market trading on Thursday. The sharp gain suggested optimism around the takeover terms and the strategic value Lilly sees in the company’s pipeline.

The acquisition points to a broader industry push to find new approaches for hard-to-treat mental health disorders. By targeting a biotech focused on psychedelic-related drug development, Lilly appears to be betting that emerging neuroscience treatments could open a new avenue in psychiatric medicine.

For Lilly, the proposed purchase adds to its efforts to strengthen its pharmaceutical portfolio beyond its existing businesses. For the biotech sector, the deal highlights continued interest from large drugmakers in earlier-stage companies developing next-generation therapies for depression and related disorders.