Also see Bulimia

Anorexia nervosa may occur after age 25 in females [41, 42, 43]. The oldest reported patient was a 68-year-old woman with no prior history of eating disturbance. While the incidence of anorexia in the general population is 0.37 per 100,000 [44] the incidence of anorexia nervosa in old age is unknown. Less than 100 older patients, both male and female, have been reported in the world’s literature [25, 41, 43, 45, 46, 47]. Adult-onset causes usually come from upper-middle class families [41]. Anorexia nervosa in susceptible patients include those with multiple surgical procedures or illnesses [45], stress secondary to childbirth or marriage [46], or death of a spouse [42]. Sloan and Leichner [48] recently described six anorectic women, first hospitalized as adults, who were sexually abused in childhood or adolescence. In married anorectics whose dependency needs have been shifted to their children, the child’s absence resulting from moving or marriage has been associated with an acute onset of anorexia [41].

Numerous onset patterns have been described. The most common pattern is one in which the patient has a chronic eating disturbance or peculiar eating habits and a stress produces a full-blown clinical expression of anorexia nervosa. In other patients, an anorexia episode may have occurred as an adolescent, followed by a long remission, with stressful events serving to precipitate anorexia at a later time in young adulthood. The most uncommon pattern is an adult patient who develops anorexia nervosa de novo [43]. The therapist must obtain a very detailed history of the patient’s early eating patterns to determine if a prior episode occurred.

Some patients who exhibit pure restrictive anorexia develop bulimia during or after treatment. Failure of symptomatic restraint may first be manifested in bulimic episodes. Vandereycken [43] suggests that some anorectics who fail treatment develop vomiting, purging, or frank bulimia. Kellett [46] described a 52-year-old woman who purged and vomited in addition to the anorexia.

In a study of fifty married patients, Dally [41] divided anorectics into four groups. In group I, onset of anorexia started during the engagement period prior to marriage. In group II, onset occurred while subjects were married and prior to pregnancy. Onset in group III occurred within three years of becoming pregnant. The period after menopause marked the onset of anorexia in group IV. Dally felt that the anorexia that developed in groups I and II was a maladaptive solution to an emerging marital crisis. Dally [41] notes that group IV post-menopausal-onset anorectics are markedly depressed and suicidal and may have a more ominous course than their younger counterparts.

The course of anorexia nervosa in later life is variable. Crisp [49] notes that some chronic anorexic patients who have the illness throughout their reproductive life (puberty to menopause), shed the illness at menopause, while others remain ill, surviving as "isolated, eccentric and wizened old ladies." Vandereycken [43] conceptualizes anorexia as an incurable illness in some patients with spontaneously occurring remissions and exacerbations. This chronic course seen in older patients is a form of "process" anorexia nervosa, as differentiated from a more "reactive," self-limited disorder seen in younger, mainly adolescent patients.

Though some patients with late onset or chronic anorexia nervosa may recover after intensive treatment, patients failing to maintain their weight at four- to eight-year follow-ups may have to inevitably recognize their decision to remain anorectics. In these cases, the goal of treatment is to minimize the physical and emotional handicaps of the disease. Vandereycken [43] raises ethical questions concerning treatment of chronic anorectics and bulimics. Although the patients may feel life is barren with anorexia, life may become even more barren and painful without it. Furthermore, chronic bulimics can organize their life around the bulimia, with bulimic episodes becoming "institutionalized."