Hello and welcome to Healthcare Magic. Thanks for your query. I understand that you are concerned about the behavioural changes that you are noticing in your borother. The symptoms that you have described such as acting strange, being withdrawn and isolated, and having erratic sleep patterns could indicate that he is having a psychiatric disorder. These symptoms can be seen in a psychotic disorder or a mood disorder like depression. However a detailed history and psychological assessment is necessary to pin-point the diagnosis. Since you have mentioned that these symptoms are significant and that even his friend have noticed him behaving strangely, it is essential that he needs a psychiatric evaluation. So, I will suggest that you take him to a psychiatrist as early as possible. Earlier the problem is diagnosed, better will be the treatment outcome. There are effective treatment options - in the form of medication and psychotherapy, which will help you overcome your problems. So, please take him to a psychiatrist for further evaluation and treatment. Wish you all the best. Regards, Dr. Jonas Sundarakumar Consultant Psychiatrist