A 2018 study by Kupferstein found that 46% of autistic people exposed to ABA, as an adult or as a child, met the diagnostic criteria for Post-Traumatic Stress Disorder. In addition, the severity of post-traumatic stress symptoms correlated positively with the length of time spent in ABA. The results of this study suggest that short-term benefits of ABA are outweighed by the long-term costs. This study was not accepted without critique: a follow-up study by Leaf et al. critiqued many aspects of Kupferstein’s study design, including hypothesis testing bias, vague operational definition of ABA, and for not confirming the diagnoses of its participants before running the study. However, others have critiqued the follow-up study as well, noting that Leaf et. al were funded by donors who support the use of ABA therapy for autistic individuals. Given the deep controversy around the issue of ABA and post-traumatic stress symptoms, there is ample room for further follow-up studies.