Early in the novel, it is revealed that both Anna and Molly have experience undergoing psychoanalysis. This plot point becomes more important as readers see several scenes where Anna interacts with her analyst, Mrs. Marks, who is informally known as "Mother Sugar." Psychoanalysis is a type of therapeutic treatment that developed as a precursor to modern psychology and psychiatry. Psychoanalysis was first developed as a practice by Sigmund Freud in the 1890s, although other practitioners later developed different schools of thought and approaches to the practice.
Psychoanalysis relies on a theory of the unconscious, in which someone's thoughts and actions are rooted in instinctual impulses of which they are not consciously aware. Moreover, when those drives surface, most individuals will respond with defense mechanisms to prevent themselves from becoming truly aware of them. The conflict between the conscious mind and the repressed unconscious, according to this theory, can lead to problems such as anxiety, depression, neurosis, and hysteria. It is worth noting that some of the conditions psychoanalysis was developed to treat have since been analyzed through newer scientific models of mental illness, while others have been largely debunked or otherwise reconceived by the scientific community.
Practitioners of psychoanalysis believed that the unconscious was revealed through dreams and unintentional actions, such as accidentally saying something other than what was intended ("Freudian slips"). If this material could be surfaced and brought into the conscious mind, the tension between consciousness and unconsciousness could be resolved. Treatment was typically frequent and involved the patient articulating his or her thoughts, dreams, and fantasies so that the analyst could probe further and help them to understand what might be being revealed about their subconscious.
The role of psychoanalysis in Lessing's novel explains Anna's interest in her dreams: both she and Mother Sugar believe these reveal something about the workings of her unconscious mind. The idea of a repressed unconscious that is both difficult to access and essential to self-actualization is also reflected in Anna's struggle to say what she means and write in an authentic way. Anna's writer's block seems to be connected to her repression. Psychoanalytic theory is also reflected in Anna's description of her sexuality since she is concerned with having different types of orgasms and what this might reveal about her. Freud had theorized several stages of sexual development and identified them with different types of sexual gratification.