Social media tends to be very addictive, and TikTok is no different. TikTok's special algorithm analyzes what a person has viewed and liked and focuses content that's related to that to keep users coming back. Also, TikTok's specific format of short videos and ease of scrolling causes what research refers to as being "caught in an entertainment spiral." In short, TikTok is undoubtedly addicting.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11710882/
I used the primary source of a qualitative study by the National Library of Medicine, who collected data through in-depth interviews and surveys of 56 mixed-gender participants. It found that people who used TikTok excessively, for instance 6 hours or above, showed real addictive signs such as attention deficits and procrastination.
https://www.addictioncenter.com/behavioral-addictions/social-media-addiction/tiktok-addiction/
I used the secondary source of an article published by the Addiction Center, who specializes in what causes something to be addictive. This source highlighted the "entertainment spiral" and TikTok's special algorithm.
There shouldn't be much of a bias in either of these sources, neither has much of a stake in whether TikTok is successful or not. Both sources are just focused on providing accurate information for the public.
There have been a number of highly qualified individuals who've openly advocated for less TikTok use. James A Roberts, PH.D. says the opportunity cost of social media(TikTok) is huge. The more time we spend scrolling, the less time we have for the activities that build real connection and meaning."
There's not much evidence that TikTok isn't addicting, the only counter is that the benefits of TikTok, such as quick access to information and opportunity for public growth, outweigh the costs.