Personality Disorders: Description, Aetiology, and Epidemiology Victor Molinari and Daniel L. Segal

AETIOLOGY

Because personality disorders and personality disorder features begin relatively early in life and have a generally persisting impact across the lifespan, it can be assumed that the aetiology of personality disorders includes psychosocial and biological factors³. Concerning personality disorder among older adults, it is helpful to focus on dimensional aspects of personality as well as the categorical diagnosis of personality disorder.

Psychosocial Factors

Freud noted the importance of Axis II traits in the aetiology of Axis I symptoms. He embedded the idea of personality within his psy-chosexual schema regarding oral, anal, oedipal, latency and genital stages. Inborn temperamental traits combine with parental influences in these early developmental periods to shape an individual’s personality. How early figures react to the growing child’s bio-psycho-social needs forges a rigid template that is operative throughout the person’s life, and reflects whether the person will satisfy his or her intrapsychic and interpersonal needs in an adaptive manner or in an exaggerated repetitious fashion. Acute symptomatology erupts when current stressors intersect with the psychosocial dynamics and interpersonal sensitivities laid out in early childhood forming this hard bedrock of personality traits. Working from this grand model, Freud erroneously concluded that by the age of 40 personality patterns were invariably set, and advised psychoanalysts to spend their time with younger analysands.

Erik Erikson⁴ enhanced the Freudian framework to include three stages of adulthood that were yoked to specific life challenges. Those in young adulthood are faced with the crisis of deciding on a career and achieving intimacy; those in middle adulthood raise their family, maintain a career and hopefully become generative; those in late adulthood are confronted with preparing for death, gaining wisdom and achieving ego integrity. Unfortunately, the heuristic value of these conceptualizations has not been realized because limited research has been conducted to validate these stages.

Coming from a more empirical tradition, Costa and McCrae⁵ conducted both cross-sectional and longitudinal research with their well-validated NEO Personality Inventory (which measures five broad lexically derived personality factors of neuroticism, extraversion, openness, agreeableness and conscientiousness) and concluded that there is general continuity of personality across the life span. However, other researchers have argued that Costa and McCrae’s five-factor model tends to minimize personality change in adulthood, particularly with respect to environmental factors⁶. Indeed, in his 50-year follow-up study of Harvard undergraduates, Vaillant⁷ discovered that significant change can occur for certain individuals, related either to specific negative or positive adult life events (e.g. alcoholism; supportive spouse). Consistent with these formulations, Identity Process Theory⁸ postulates that older adults tend first to assimilate and (if assimilation is non-successful) then to accommodate discrepant experiences to maintain self-esteem via a consistent sense of self. Those with rigid understandings of themselves that characterize personality disorders may be less able to employ these more mature coping mechanisms and negotiate the vagaries of ageing. From this conceptual basis, too much or too little stability in personality as we age may become maladaptive.

Finally, a well-researched cognitive model of psychopathology suggests that personality disorders may be characterized by cognitive distortions which are derived from biases in information processing and dysfunctional schema or core beliefs that influence people’s perceptions and thoughts at the conscious level⁹. Examples of cognitive distortions include all-or-none thinking (seeing personal qualities or situations in absolutist ‘black and white’ terms, and failing to see shades of grey), catastrophizing (perceiving negative events as intolerable calamities, commonly referred to as ‘making mountains out of molehills’), magnification and minimization (exaggerating the importance of negative characteristics and experiences while discounting the importance of positive characteristics and experiences) and personalization (assuming one is the cause of an event when other factors are also responsible). Schemas are often expressed as unconditional evaluations about the self and others. Some examples include beliefs that: ‘I am incompetent’, ‘I am defective’, ‘I am unlovable’, ‘I am special’, ‘Others are hurtful and not to be trusted’, ‘Others need to take care of me’, and ‘Others must love and admire me’. Schemas are generally thought to be formed early in life but to persist if no conscious effort is made to identify, examine and challenge them.

Some examples of cognitive distortions and schema relevant to specific personality disorders include:

an individual with paranoid personality disorder is prone to habitually and chronically perceive others as deceitful, abusive and threatening;
an individual with borderline personality disorder is prone to sort people into categories of either ‘all good’ or ‘all bad’;
an individual with obsessive-compulsive personality disorder tends to be a slave to the belief that he or she must be perfect and always in control;
an individual with dependent personality disorder sees him- or herself as weak, incompetent and inadequate, requiring constant reassurance, nurturance and direction.

Whereas a few studies have attempted to validate the specific relationships between core beliefs and personality disorder pathology¹⁰, notably lacking are studies that specifically examine these relationships in older adult samples.

Genetic Factors

A growing literature base has focused on the genetic factors that contribute to personality disorders. In a study of 483 adult twin pairs, Jang et al.¹¹ found a median heritability of 0.44 for 66 of 69 personality disorder facet traits. Similar data were reported by Coolidge et al.¹² who found a median heritability coefficient of 0.75 for 12 specific personality disorders in their sample of 112 child twin pairs. Interestingly, Jang et al.¹³ found in their cross-sectional twin study that genetic contributions to personality disorder traits actually increase with age. Torgersen et al.¹⁴ used a structured interview to diagnose the full range of personality disorders, finding an overall heritability estimate of .60. Finally, a very recent study with a large sample of young adult Norwegian twins found one genetic factor reflecting a broad vulnerability to personality disorder pathology and negative emotionality whereas two other genetic factors more specifically reflected high impulsivity/low agreeableness and introversion¹⁵. In summary, there is clear evidence of heritability for some personality disorders but much that remains unexamined. Perhaps the best conclusion from this data is that heritable traits play a significant role in the formation of personality disorders but heritability alone does not directly cause an individual to develop a specific personality disorder.

DIAGNOSIS

The diagnosis of personality disorders is known to be particularly challenging across the lifespan. Specifically, in adulthood, it is generally difficult to distinguish one personality disorder from another¹⁶. Later life adds further complications to diagnosis. There are, for instance, problems in obtaining a reliable diagnosis and, at present, there is no ‘gold standard’ of diagnosis for personality disorder in older adults. Molinari et al.¹⁷ studied geropsychiatric inpatients with depression, and found general discordance between patient self-report, family informant ratings, social worker evaluations and consensus case conference categorical diagnosis of personality disorder. It appears that there are varied perceptions of an individual’s personality, all of which should be taken into account for a comprehensive evaluation of Axis II pathology.

Personality disorder is commonly seen in practice settings yet seldom formally identified. Mental health professionals are loathe to diagnose it, particularly in old age, due to concerns over pejorative bias, pessimistic beliefs about the prospects of therapeutic change for personality disorder pathology, managed care reimbursement biases, and focus on medical or Axis I pathology (particularly cognitive impairment) in old age. Often the patient with personality disorder presents in a demanding, blaming manner with an inappropriate, rigid interpersonal stance and limited insight. Unfortunately these same features are sometimes erroneously interpreted as part of the natural ageing process¹⁸. Perhaps it is most important to recognize that ‘either/or’ thinking is often incorrect in the diagnosis of older adults. Comorbidity is the rule rather than the exception, with research consistently finding that older adults with depression also may have longstanding maladaptive personality disorder traits^18–20.

Another factor that impacts identification and diagnosis of personality disorders in later life is that, in some cases, there is an emergence of personality disorder symptoms that were ‘hidden’ earlier in life³. For example, consider a highly dependent woman who was supported by a caring, perhaps dominating, spouse who did not mind making all of the decisions for the couple and essentially took care of his wife throughout much of their adult lives. It would not be until she struggled to take care of herself after becoming a widow that the extent of her ‘disorder’ would become recognized and perhaps diagnosed. A final diagnostic challenge is that the sets of diagnostic criteria do not fit older adults as well as they do younger adults³. In an empirical investigation of potential age-bias using item analysis, Balsis et al.²¹ found evidence of age-bias in 29% of the criteria for seven personality disorders. In this study, some diagnostic criteria were differentially endorsed by younger and older adults with equivalent personality disorder pathology, suggesting a bias.

EPIDEMIOLOGY

Some early anecdotal reports suggested that personality characteristics become uniformly less harsh with age^22,23

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