Michael Wm. MacGregor

The role of defense mechanisms in borderline and antisocial personalities.

We examined whether borderline personality disorder (BPD) and antisocial personality disorder (APD) could be differentiated based on defense mechanisms as measured by observer (Defense-Q; MacGregor, Olson, Presniak, & Davidson, 2008) and self-report (Defense Style Questionnaire; Andrews, Singh, & Bond, 1993) measures. We conducted 2 studies whereby nonclinical participants were divided into borderline and antisocial groups based on scores from the Personality Assessment Inventory (Morey, 1991). Multivariate analysis of variance results revealed significant overall group differences in defense use. Univariate analyses further showed group differences on several individual defenses (e.g., acting out, denial, and turning against self). Together, the findings suggest that in BPD, the defenses may emphasize interpersonal dependency and a tendency to direct aggression toward the self; whereas in APD, the defenses may emphasize egocentricity, interpersonal exploitation, and a tendency to direct aggression toward others. Overall, this study demonstrates important differences in defense use between borderline and antisocial personality groups across both observer and self-report measures.

Gender differences in the relation between tnterview-derived hostility scores and resting blood pressure

We examined the correlations between Structured Interview (SI)-derived hostility scores and resting blood pressure (BP) to see if they would be the same or different for healthy men and women. Standard risk factor information and resting BP measures were obtained from 193 undergraduates (109 men, 84 women), who underwent the SI. Subjects were rated for Potential for Hostility, Hostile Style, Intensity and Content, and completed Antagonism and Neuroticism scales. As expected, SI hostility scores were related to higher resting SBP in men, however, in women, they were related to lower resting SBP and Neuroticism. Regression analyses controlling for standard CHD risk factors indicated that SI-derived hostility predicted resting SBP and hypertensive status in both men and women, though in opposite directions. Thus, SI-derived hostility may assess a different construct in women than in men.

The relation between defense use and adaptive behavior

Abstract In two studies we examine the association between a person’s pattern of defense use, assessed by a new measure called the Defense-Q, and their adaptive behavior. We compare each person’s Defense-Q profile to a theoretical Adaptive Defense Profile (ADP) to obtain an ADP similarity score. In Study 1 we show in a student sample that ADP similarity scores are positively related to observed empathy and competence and negatively to hostility. In Study 2 we demonstrate in a population-based community sample that ADP similarity scores are positively related to nurse’s ratings of competence and nutritional based weight control programs and negatively related to hostility, depression, alcohol use, and weight control through the use of pills. These results suggest that defense use is related to adaptive behavior in a theoretically consistent manner, and that the Defense-Q shows promise as an observer-based instrument to assess defenses.

Adaptive defense use and resting blood pressure in a population-based sample.

OBJECTIVES There is an accumulating body of research related to the psychosomatic study of blood pressure. One variable that has received attention is defense use. We examined the relation between defense use and blood pressure in men and women of different ages. METHODS A random sample of 667 participants was selected from a population-based study. Resting blood pressure was obtained, and each participant was rated for defense use by a trained observer using Defense-Q. An Adaptive Defense Profile (ADP) score was calculated for each participant, and this score was related to blood pressure. RESULTS Regression analyses revealed a significant main effect for the ADP score for both diastolic and systolic blood pressure. Those persons with higher ADP scores had lower diastolic and systolic blood pressure. As well, a significant Age x Sex x ADP score interaction was found for diastolic blood pressure. Older women with a less ADP score had higher diastolic blood pressure. CONCLUSIONS These findings suggest the continued investigation of defense use and blood pressure.

Coder gender and potential for hostility ratings.

This study examined the effects of coder gender on Potential for Hostility ratings. Six trained coders (3 men and 3 women) who were unaware of the coder gender effect hypothesis coded 30 male and 30 female undergraduates for Potential for Hostility. Although reliability estimates as calculated by Cronbachs alpha suggested that all coders were consistent, an analysis of variance revealed a significant main effect for coder gender, wherein female coders rated participants as displaying significantly less Potential for Hostility than did male coders. This significant difference was also meaningful, as coder gender accounted for 32% of the variance in Potential for Hostility scores. Thus, future Potential for Hostility investigations need to consider the gender of those coding, as this factor both significantly and substantially influences reported Potential for Hostility ratings.

Differentiation of Depression and Anxiety Groups Using Defense Mechanisms

We examined whether participants in depressed and anxious groups could be classified correctly using observer and self-report measures of defense mechanisms. A sample of 1182 university students completed the Personality Assessment Inventory and those scoring in the clinical range on either depression or anxiety indices were selected for participation. In total, 25 participants met criteria for the depressed group and 94 met criteria for the anxious group. Individual defense scores from the Defense-Q and the Defense Style Questionnaire were separately entered into 2 stepwise discriminant analyses. After cross-validation, the Defense-Q and Defense Style Questionnaire analyses classified participants with 75.0% and 71.3% accuracy, respectively. The results indicated that depression and anxiety groups can be significantly differentiated by defense use alone. Important differences in defensive functioning between these groups were confirmed and differences between observer and self-report measures of defenses mechanisms and current challenges in defense research were highlighted.

Personality Assessment Inventory profiles of university students with eating disorders

BackgroundEating disorders are complex disorders that involve medical and psychological symptoms. Understanding the psychological factors associated with different eating disorders is important for assessment, diagnosis, and treatment.MethodsThis study sought to determine on which of the 22 Personality Assessment Inventory (PAI) scales patients with anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified (EDNOS) differed, and whether the PAI can be used to classify eating disorder subtypes. Because we were interested in both whether the PAI could be used to differentiate eating disorder subtypes from each other, as well as from other disorders, we also included a group of patients with major depression.ResultsThe three eating disorder groups did differ significantly from each other, and from the patients with depression, on a number of the PAI scales. Only two PAI scales (Anxiety and Depression), however, exceeded a T-score of 70 for the patients with anorexia nervosa, no scales exceeded a T-score of 70 for the patients with bulimia nervosa or EDNOS, and only two exceeded a T-score of 70 for the patients with depression (Depression and Suicide). A discriminant function analysis revealed an overall correct classification between the groups of 81.6%.ConclusionsThe PAI helps to understand the psychological factors associated with eating disorders and can be used to assist with assessment. Continued investigation using the PAI in an eating disordered population is supported.