BritishJournal of Psychiatry(1992),160, 257—260

Anorexia

Nervosa

of Late Onset

N. BOAST, E. COKER and A. WAKELING Forty-two female anorexia nervosa patients, with onset of first illness at 25 or more years

of age, are described and compared with 143 patients with onset of first illness between

the ages of 15 and 20 years. The data support the view that the older group forms part of

the total population of anorexia nervosa patients, but that age exerts a pathoplastic influence on psychopathology and psychosocial stressors. Older patients lost more weight, but did not have significantly

higher rates of concurrent

mood disorder.

Anorexia nervosa occurs characteristically in females during adolescence. Thus, whereas the disorder can develop in pre-pubertal children (Fosson et al, 1987), and there have been case reports of illness beginning after the menopause (Hsu & Zimmer, 1988), most published studies report peak onset during adolescence. Age of onset has been incorporated into diagnostic criteria; for example, Feighner et al(1972) insist on onset before the age of 25. DSM—III—R (American Psychiatric Association, 1987), however, acknowledges that cases can commence in the subject's early 30s, although this is regarded as rare. Theander (1970) and Garfinkel & Garner (1982) have calculated that 3-5% of all cases of anorexia nervosa develop after the age of 25. There is recent evidence to suggest that the incidence of anorexia nervosa is increasing (Szmukler,

1985) and that it is now occurring

across a wider social and cultural base than hitherto (Robinson & Anderson, 1985). As part of this process, Hsu & Zimmer (1988) have suggested that the rates of eating disorder in older patients may be increasing. However, other than in relationship to marriage (Daily, 1984), subjects with anorexia nervosa

with a later onset have received little detailed scrutiny.

The pathoplastic influences of age might be expected to affect the mode of onset, clinical features and outcome of anorexia nervosa, but specific knowledge in this area is lacking. Follow-up studies have suggested that the subject being older at onset is an indicator of poorer outcome (Morgan & Russell, 1975; Hsu et al, 1979). Clinical impression suggests that late-onset cases present with more depressive features than those cases with onset during adolescence. This study presents data on a group of patients with an onset of anorexia nervosa after the age of 25. A comparison is made with patients with an age of onset between 15 and 20.

Free Hospital between 1971and 1987.Diagnosis of anorexia

nervosa was established on the basis of Russell's (1970) criteria: patients exhibited self-induced weight loss brought

about by food restriction, a distinctive psychopathology of

a morbidfearof weightgainand ofattaining an appropriate

weight, and amenorrhoea. Other types of behaviour aimed at maintaining weight loss, such as excessive exercise, vomiting and laxative abuse, were frequently associated. Two groups of female patients were selected for study. A late-onset group comprised all female patients with a clearly defined first illness and an onset at or after the age of 25; recurrent

or chronic unremitting

cases with an early

age of onset were thus excluded from this group. A peak onset group included those female patients with a first onset of illness between the ages of 15 and 20 who had consulted

before the age of 25.

Cases were identified as follows. Out of 491 eating-disorder cases seen between 1971 and 1982, 69 cases failed to meet

Rusell's (1970) criteria for anorexia nervosa, 72 cases met

criteria

for bulimia

specific

aspects

nervosa,

47 had other diagnoses

and data

were missing for five cases. The remaining 298 cases met Russell's (1970)criteria for anorexia nervosa. These 298 cases included 143 peak-onset and 33 late-onset cases as defined above. There were 14male patients and in 10cases data were insufficient for analysis. The other 98 cases had onset below age 15or between ages 20 and 25, or peak age of onset with consultation after age 25. The late-onset group thus consti tuted ll°lo(33/298) of patients with a specific diagnosis of anorexia nervosa seen between 1971and 1982at the Royal Free Unit. A further nine late-onset cases seen between 1983 and 1987did not differ fundamentally from the other late onset cases and were therefore included in the analysis. The case notes were systematically assessed using a stan dardised recording and coding sheet. Demographic details, of history,

psychopathology,

physical

examination, treatment and outcome were elicited. Data were not available for every patient on each of the items studied. Data programs and analysis were undertaken

utilising the spss software package. Statistical tests used

were the unpaired 1-test for quantitative data (weights) and

the x2 test for qualitative (categorical) data.

Resufts

Method The study was of retrospective design using case records of patients referred to the eating disorders unit at the Royal

257

Data were collected on 185 patients. There were 143 patients

in the peak-onset group and 42 in the late-onset group. The

258

BOAST ET AL

Table 1 Means and standard deviationsof important clinicalfeatures

in late- and peak-onset anorexia nervosa groups onset

VariablesLate

(n=42) mean

s.d.Age (years):at eating-pattern change29.7 1.8at onset of anorexia nervosa32.1 1.5at first consultation35.4 2.5Age 1.4Height: atmenarche: years12.9

metres1.62

onset (n=143)

s.d.Peak mean

Table 3 A comparison of previous physical and psychiatric illness

(data transformed to percentages after analysis)

VariableLate

onset: onset:

%Peak

%x2pPrevious

illness532012.2