If you can create a reference to a book, you are also able to create a reference to a book chapter. You should cite a chapter in the event that you did not read the whole book and you draw information from just one chapter.
Budson AE, Solomon PR. Memory loss, Alzheimer's disease, and dementia. 2nd ed. Edinburgh: Elsevier; 2016. Chapter 23, Non-pharmacological treatment of the behavioral and psychological symptoms of dementia; p. 218-225.