From a scientific perspective, existential psychotherapy:

Existential psychotherapy is characterized by its focus on individual experiences, subjective realities, and the inherent complexities of human existence. This therapeutic approach prioritizes understanding personal meaning, values, and the client’s unique context, which makes each psychotherapy experience distinct. As a result, research in this field poses significant challenges, since standardizing the therapeutic process or generalizing outcomes can overlook the nuances essential to each individual's journey.

The nature of existential therapy typically resists quantifiable measures that can easily be applied or interpreted uniformly across different clients, as the therapeutic relationship is built on personal, often existentially profound themes such as freedom, isolation, and mortality. Therefore, the difficulties arise from the personalized nature of the therapy and the varied subjective experiences of clients, making it challenging to fit into traditional empirical research models that seek consistency and replicability.