The Enchiridion of Epictetus, is written by Arrian of Nicodemia, but often attributed to Epictetus himself. Arrian was his student in philosophy who adapted the Discourses of Epictetus for this book, adding his own emphasis. Essentially Enchiridion is an ancient self-help book. In keeping with the philosophy of his master, Arrian describes stoicism through the lens of personal improvement and mental health, although he obviously does not employ these terms.
Arrian's take on his master's teachings is one of personal reconciliation on behalf of the individual to the reality of the external world. He begins the book with an explanation of what is within the individual's control and what is not. Basically only the mental sphere is open for the individual's manipulation. Everything else exists outside of the control of the individual and must be accepted as is.
Arrian is interested in helping his readers make sense of their realities in regards to control. If he had been writing in a post-Freudian world, he likely would have described his pursuit as the systematic elimination of psychosis and neurosis -- both of which are misunderstandings of the extent of the individual's control. Psychosis occurs when a person ignores the arenas which are under their control, believing that they have no control there. To Epictetus, the individual must control their own mental faculties. Neurosis, on the other hand, is a misconception of the limits of one's control, often leading to delusions and extreme frustration. Epictetus outright denies the validity of this error. He argues that a person must control their mind and nothing else. Everything external and physical is outside the domain of the individual.
