Sub Genres

Within the thriller genre there are many differnt themes within the films which make the seem completely different to one another in terms of mise-en-scen characters and narrativfe. To differentiate these differnt types from one another is to have sub-genres.
Sub-genres are a genre within a genre that helps classify the specific themes of that film. 
Some examples of sub-genres within thriller are psychological thriller. 
The similarities of these two films that both come under the psychological thriller genre is that in the narrative events they both towards the end come to the realization of disturbed thoughts and alteration of reality to themselves. both these characters are the main characters within the film therefore we feel empathy towards them so when, at the end, the come to realization of mental problems is shocks the audience and adds surprise to the original pre-emptions of the events in the film. This is my favorite sub genre of thriller as it shocks you and makes you reconsider previous events watched in the film therefore changing your thoughts and making you re think you feelings created originally by the other characters.