Hi, What is happening with your friend is quite uncommon. There are very few case reports of dettol addiction in medical literature, mainly because of the presence of isopropyl alcohol which has high addiction potential and harm too, especially to central nervous system, oral and GI mucosa. The salience of the case are worth noting and learning. Based on the information provided by you, It can not be concluded if he is actually addicted to/dependent on dettol. One similar case in history' found to be obsessed with cleaning which led to the onset of dettol consumption. We need to go in to the detailed explanations and assess his experiences & thought process regarding initiation and maintenance of the substance use. Accordingly a management plan can be formulated which will benefit him for sure. Remember it requires a multimodal approach to tackle such case where an addiction psychiatrist works in close collaboration with an skilled psychologist (if needed)

Hello any kind of addiction when it crosses certain beyond limits then it become harmful and mostly people who are either depressed or anxious they e just started taking substances for reduced anxiety n relieving from their conflicts  but this is not solution. You hould take your friend to psychiatrist he needs proper treatment