Early 20th century; earliest use found in The Academy: a monthly record of literature, learning, science, and art. From psycho- + therapeutical, after psychotherapy.
Definition of psychotherapeutical in US English:
psychotherapeutical
adjectiveˌsʌɪkəʊˌθɛrəˈpjuːtɪkl
Psychotherapeutic.
Origin
Early 20th century; earliest use found in The Academy: a monthly record of literature, learning, science, and art. From psycho- + therapeutical, after psychotherapy.