AN EXPERIMENTAL INVESTIGATION OF SIMULATION AND PSEUDO‐DEMENTIA PART II

Summary Eighteen normal subjects were asked to simulate mental disorder following which each was submitted to a standardised psychiatric examination. The clinical pictures simulated by these subjects are described and discussed. The results of formal mental testing were contrasted with those obtained by a similar examination of a normal non‐simulating group, a group of patients with organic dementia and a group exhibiting pseudo‐dementia. In relation to the number and quality of the errors made, certain differences are demonstrable between these four groups. The main differences observed were: 1. The highest number of negative or omission errors were committed by the pseudo‐dements, followed in order of frequency by simulants, organics and normal non‐simulating subjects. This can probably be construed as a measure of non co‐operation or unwillingness to answer even when the correct answer was known. 2. Simple approximations or “near miss’ answers (e. g. 2 + 2 = 5) were given more frequently by patients with pseudo‐dementia than by simulants, normals or those with organic dementia, though were given at times by subjects from all groups. 3. Although examples of vorbeireden occurred frequently in the replies given by both simulants and patients with pseudo‐dementia, similar gross confabulations occurred with almost equal frequency in the responses of organic patients. So far as the simulants were concerned, some insight into the mechanism of production of the responses was gained by retrospective inquiry. This mechanism is probably analogous to that governing some of the responses of those with pseudo‐dementia, though not those of organic patients. 4. Transposition and reversal errors (e. g. of given digits, the order of months etc.) are not the particular prerogative of simulants or those with pseudodementia, but were committed also by organic patients and in the latter case resulted either from defect of attention or perseveration. 5. Perseveration was a marked feature in the responses of organic subjects and was not observed to any substantial degree in the responses of subjects in the other three groups. 6. So far as simulants are concerned, the length and thoroughness of examination is an important factor in revealing the spuriousness of simulation. Because the simulant's role is difficult to sustain there is a tendency for fatigue to increase the pull of reality and to result in responses becoming more and more normal. In pseudo‐dementia the same process may be at work, but in this case the patients respond with increasing unco‐operativeness. 7. Certain other differences observed between the performance of patients with pseudo‐dementia and that of normal volunteer simulants indicate that the clinical picture of experimental simulation is not qualitatively completely similar to that observed in pseudo‐dementia. For this reason assumptions cannot safely be made on this topic in the light of information gained from an experimental investigation of simulation.