Comparison with Other Studies

The instrument used in this study to examine personality change allows respondents to record either an increase or a decrease in a range of traits. This is unlike the majority of studies discussed in the literature review, where most instruments only record either an increase in, or the occurrence of, specific personality characteristics. Three studies, however, did use instruments which allow the informant to report either an increase or a decrease in personality traits. Each of these studies asked informants to complete a personality questionnaire about their relative before they developed dementia and again, as they are currently. Petry et al. (1988) found that for each characteristic, all their informants reported change in the same direction. Both Siegler et al. (1991) and Chatterjee et al. (1992), using the NEO-PI, found that the rank order of their subjects' personality characteristics were usually the same before and after developing dementia. In the current study, some characteristics were reported as changing in either direction. While for most of the clusters almost all informants have reported change in the same direction, some clusters show a more 2- sided distribution. These include inhibition, passivity, thoughtlessness, caution, emotionality and imperceptiveness. While every effort was made to remove any ambiguous clusters, thoughtlessness and imperceptiveness still contain negative adjectives which may have made interpretation difficult and would explain the 2-sided

distribution. The remaining clusters may, however, genuinely indicate that some informants are reporting an increase in these traits while others are reporting a decrease.

6.3.1 Apathy

The clusters of aloofness, inhibition and passivity would most closely equate with the characteristic of apathy. Aloofness was reported to increase in 50% of the DAT patients and 66% of the NSW Alzheimer's Association sample. For the clusters,

inhibition and passivity, about 40% of informants reported increases, while a similar percent reported decreases. These clusters contain the adjectives restrained, docile, submissive and passive and it would seem possible that those who show a decrease in these characteristics are showing increased restlessness, agitation and possibly aggression. These behavioural characteristics were not assessed in this study as they were considered to fall outside the range of normal personality traits. Only two other studies have looked at change in these characteristics. Rubin et al. (1987a) found a lower occurrence of passive behaviours than the current study, while Bozzola et al. (1992) found that 61% of informants reported an increase in apathy. This latter Figure was similar to that found in the current study. Other studies looking at the occurrence of behaviours found that apathy was reported in between 20% and nearly 50% of cases (Teri et al., 1989; Bums et al., 1990b; Lachs et al., 1992; Cohan et al.,

1993).

6.3.2 Underactivity

The clusters, energy level and lethargy fall into this category. This study found that around 70% of the DAT sample and 80% of the NSW Alzheimer's Association sample showed at least some decrease in energy and increase in lethargy. Other studies looking at personality change, while not reporting the percentage showing change, have all found a significant decrease in energy and physical activity. Studies reporting the occurrence of underactivity vary from 7% to 43% (Teri et al., 1989; Sultzer et al., 1992; Ballinger et al., 1982), which is considerably less than this study. In the current study, 41% of the control group were thought to have decreased energy level, suggesting that this may be, not unexpectedly, a normal part of ageing.

6.3.3 Stubbornness

In this study, 50% of the DAT patients and 62% of the NSW Alzheimer's Association sample were reported to have shown some increase in stubbornness. This is more than that reported by either Rubin et al. (1987a) for whom 21% were reported to show an increase in this trait, or Bozzola et al. (1992) who reported that 41%

showed an increase. However, Gustafson (1975) found that 58% showed some evidence of stubbornness which is very close to that reported in the current study.

6.3.4 Self-centredness

In the current study, the cluster thoughtlessness contains the single adjective,

inconsiderate. This negative adjective may account for the 2-sided distribution of

this cluster, with an almost equal number reporting a decrease as reported an increase. About 25% reported an increase in thoughtlessness for both the DAT and the NSW Alzheimer's Association samples, which is similar to the number reporting such changes in the studies by Rubin et al. (1987a) and Bozzola et al. (1992). It is possible that informants misunderstood the negative adjectives in this cluster and most if not all, intended to report an increase in this trait. This would have resulted in about 50% reporting an increase which is high compared to other studies.

6.3.5 Coarse / Crude Behaviour

The clusters, empathy and courtesy have been included under this section as it was considered likely that decreases in such traits could be reflected in coarse, crude or socially inappropriate behaviour. This study found that around 30% of the DAT patients were reported to show some decrease in empathy, although the NSW Alzheimer's Association sample reported some decrease in this trait in nearly 50% of cases. This level of occurrence is similar to a number of the studies discussed earlier, with Bozzola et al. (1992) reporting this characteristic in 36% of subjects and Sultzer et al. (1992) noting a mild level in 34% during clinical interviews. Ballinger et al. (1982) and Gustafson (1975), however, reported higher levels of over 50%.

6.3.6 Irritability / Volatility

Forty four percent of the DAT sample and 53% of the NSW Alzheimer's Association sample reported some increase in irritability. This is a much higher percentage than most other studies that have looked at irritability in dementia. It is, however, in close agreement with the study by Bums et al. (1990b) in which they used a five item scale and found that 58% reported some degree of irritability.

6.3.7 Suspicion

A higher percentage of informants reported suspicion in the current study (approximately 60%) than has been reported by other studies. Rubin et al. (1987a) found that only 5% of their sample were reported as showing a change in suspicion. Rating scales measuring the occurrence of suspicion yielded levels of between 25% and 50%. Suspicion is often studied in association with psychiatric symptoms in dementia, extreme suspicion being viewed as a paranoid state (Mendez et al., 1990).

It is likely, however, that many demented people show greater levels of suspicion than previously without being classed as paranoid.

6.3.8 Callousness

Only Petry et al. (1988) have also looked at this trait. They found that the mean change in this trait was significantly greater in their DAT patients than in their controls, as was found in this study. The current study found that 22% of the DAT sample and 45% of the NSW Alzheimer's Association sample reported some change.

6.3.9 Emotional Lability

Emotionality was reported as increasing in about 30% of both DAT patients and the NSW Alzheimer's Association sample. About a half of this number were reported to show a decrease in this trait. The 30% increase is similar to the levels reported by those studies where clinicians have completed checklists of current behaviour (Gustafson, 1975; Bucht and Adolfsson, 1983; Sultzer et al., 1992).

6.3.10 Anxiety

In the current study, fear (which included the adjective, anxiety) was reported as having increased in approximately 65% of the subjects in both the demented samples. This is higher than that reported by most other studies. Gustafson (1975), however, reported some evidence of anxiety in 58% of demented subjects and Ballinger et al. (1982) the occurrence of anxious behaviour in 58% of their subjects.

6.3.11 General Comment on Comparison with Other Studies

For many of the traits investigated in the current study, the percent of informants reporting change is higher than found in many other studies. This may have occurred partly because this study has reported some change rather than much change. Also, information has been gathered from informants, usually carers, who know the subject well and who have ample opportunity to observe changes. Many of the studies looking at the occurrence of behaviours used clinician reports or extract behaviours mentioned by relatives at interview. The major difference in this study compared to others is the observation that changes may occur in the opposite direction to that usually encountered. Many researchers studying behaviour or personality change in dementia are interested in those changes which are distressing to carers and, as a result, the instruments used may only include such changes, neglecting other changes which may not cause distress.