The Use of Non-directive Therapy for Adolescents with Autism Spectrum Disorder: A Systematic Review Autism Spectrum Disorder (ASD) is defined as 'persistent difficulties with social communication and social interaction' and 'restricted and repetitive patterns of behaviours, activities or interests' (this includes sensory behaviour), present since early childhood, to the extent that these 'limit and impair everyday functioning' (DSM-5, 2013, sect. II). Recent research suggests one in 54 children in the US (Centers for Disease Control and Prevention, 2020) and one in 100 in the UK (British Medical Association, 2019) hold an ASD diagnosis; implying ASD prevalence is increasingly annually. Throughout this article I will refer to adolescents/children with ASD and autistic children/adolescents interchangeably, to reflect the range of terminology within the UK autism community (Kenny et al., 2015). Large scale research in the U.S conducted by Cardinal et al., (2020) sought to understand the increase in prevalence rates. The findings suggest a wider understanding of the Autism spectrum and behaviours from both lay people and professionals, resulting in higher diagnosis rates. Cardinal et al., (2020, p.135) noted a 'diagnostic migration' which has resulted in children who would have been given an alternate (and possibly incorrect) diagnosis, being identified with ASD. This research made clear that the number of children with ASD is not increasing rather diagnosis has improved. Autism has become a focus for policy makers and healthcare providers due to the high economic cost attached to support required and increasing rates of diagnosis. Cakir et al. (2020) suggests an approximate lifetime social cost of $3.6 million per ASD individual in the USA. The NHS Long-term plan (2019) identified individuals with autism and learning disabilities as a priority group and have promised investment into moving care into the community and stopping the over medication to manage behaviours of this population