The present disclosure relates to a method for generating a parameter related to a psychiatric disorder, comprising: displaying to a user a first image set, the first image set comprising a first image having a first trigger image and a second image different from the first image, such that the first image and the second image are displayed to each eye of the user; detecting a first movement of the user whilst the first image set is displayed; displaying to the user a second image set, the second image set comprising a third image having a second trigger image and a fourth image different from the third image, such that the third image and the fourth image are displayed to each eye of the user; detecting a second movement of the user whilst the second image set is displayed; and generating a parameter related to the psychiatric disorder in the user based on user activity data that is indicative of the first movement of the user and the second movement of the user.