They retain no human memory or consciousness and simply behave like animals. Usually the animals are more bloodthirsty than usual and particularly large or powerful, but they are entirely bestial. There are two main change conditions for a lycanthrope. The first is temporal. For example, from the rise until the set of a full moon.
Lycanthropic disease mediated by such conditions are often the result of secondary infections.
For instance, a helpless victim of the disease may change into a horrible beast at night whether they want to or not. Admittedly, some individuals come to relish the change. However, they still work their lives around it as opposed to controlling when it occurs. In the latter case the lycanthrope is almost always of the fusion variety and thus retains the ability to remove the item and become human again when they wish it. These are lycanthropes whose animal form is unlike a normal animal.