Hi. I appreciate your concern for your sister. Anti-tubercular drugs are known to cause psychiatric side effects. You have not mentioned about what exact symptoms she has developed, so it will be difficult to comment on it. Usually medications taje a few days to show effect and since it's only 3 days since the medications has been started, it would be recommended to wait for days. In the mean while you can discuss further course of action both with her treating physician as well as the psychiatrist.