A weakness is that this treatment doesn’t work on all types of fears for example the fear of the dark or dangerous animals which are not affected by systematic desensitisation as they may be too ingrained in our survival instincts. Furthermore, this treatment is only effective regarding specific situations and objects for example, it is less effective when treating people with a generalised anxiety disorder who have worries about imprecise situations. In order for SD to be seen as effective, it must work on curing all types of phobias and not just some.