Personality disorders cluster

The prevalence of the Cluster B disorders parallels that of the other personality disorders. Rates range from 1% to 2% of the general population for each of the Cluster B disorders. Despite these rates that parallel the other personality disorder clusters. Cluster B patients command a considerable bulk of our clinical resources. In particular, BPD is the most common of the personality disorders receiving care in most psychiatric settings. The dramatic nature of the Cluster B disorders leads to severely disruptive and erratic behavior that commands clinical attention as opposed to the quiet and unobtrusive psychopathology seen in the Cluster A and Cluster C disorders. 

Like the other personality disorders. Cluster C disorders occur at a rate of about 1-2% in the general population. APD appears to be evenly distributed between men and women. DPD is somewhat more common in women, but OCPD is slightly more common in men. 

Zwier, K.J. and Rao, U. (1994) Buspirone use in an adolescent with social phobia and mixed personality disorder (cluster A type). J Am Acad Child Adolesc Psychiatry 33 1007—1011. 

In some cases, Narcissistic Personality Disorder can cluster with both drug abuse and antisocial behavior. People with this disorder typically display grandiosity, selfishness/self-centeredness, exploitation of others, beliefs about being gifted and special, arrogance, an excessive preoccupation with self and personal appearances, and the need to have others affirm how special they are. Sometimes these qualities are difficult to separate from antisocial behavior, but key differences center around the criminal behavior and the ability to inflict physical cruelty found in antisocial behavior. Effective treatment for Narcissistic Personality Disorder includes cognitive behavioral therapy as well. 

Bipolar Syndromes. There are three distinct bipolar syndromes described in DSM-IV BRAD I, BRAD II, and cyclothymic disorder. The most severe subtype, BRAD I, is comprised of episodes of mania and/or depression. BRAD II, in contrast, is defined by episodes of hypomania and/or depression. BRAD II is arguably the most difficult to distinguish from the mood instability of patients with Cluster B personality disorders. Cyclothymic patients fluctuate between phases of hypomania and those of mild depression reminiscent of dysthymia. Although the symptoms of cyclothymia produce significant morbidity and impairment, the disability falls far... 

Cluster A Personality Disorders (Schizotypal PD, Schizoid PD, Paranoid PD). These are the odd and eccentric personality disorders. They all share certain features in common with schizophrenia, but schizotypal PD in particular appears to be most closely related to schizophrenia. The schizophrenia-like symptoms of these personality disorders (e.g., magical thinking, paranoia, social withdrawal) are less severe and generally don t impair social or employment function as severely as schizophrenia. 

The symptoms during this phase of illness are not particularly specific to schizophrenia. They often resemble, in many respects, depression or even one of the Cluster A personality disorders. The decision to initiate antipsychotic medication at this stage depends on the degree of certainty of the diagnosis, the severity of the symptoms, and the risk and benefits of the medication. 

DSM-IV divides the personality disorders into three clnsters, and within each of the three clusters, the respective disorders have a number of overlapping characteristics. To some extent, the medications that are snitable for one personality disorder are likely to be helpfnl treatments for the other disorders within the same clnster. This is an important consideration, becanse several of the personality disorders have been overlooked altogether in the treatment literatnre that has accumulated to date. For this reason, we will discnss treatment recommendations not for each individnal personality disorder bnt for each of the three clnsters. 

The rates of the Cluster A personality disorders range from 1% to 3% of the general population. STPD appears to be somewhat more common than its counterparts. Of the three, the rate for SPD is probably the hardest to determine. Schizoid patients are least likely to seek treatment on their own, and their unobtrusive (although eccentric) life style seldom leads others to insist they seek treatment. So it is difficult to be entirely certain just how many people have schizoid personalities. 

Research into the risk factors for Cluster A personality disorders has focused on genetic factors. In particular, many researchers have looked for a shared genetic linkage between these disorders and schizophrenia. Only schizotypal personality appears to be genetically linked to schizophrenia. It may be that STPD exists on a biological continuum with schizophrenia. In other words, STPD could theoretically be a far milder variant of Axis I schizophrenia. There is less evidence linking PPD or SPD to schizophrenia nevertheless, certain characteristic symptoms of these other disorders also overlap with schizophrenia. 

Other research has studied how childhood experiences may contribute to the development of a Cluster A personality disorder. Psychosocial explanations revolve around the observation that there is a degree to which distrust is a rational response to certain experiences. Some have theorized that cold and indifferent parenting can contribute to the disinterest in relationships that characterizes Cluster A disorders. It is in fact likely that a genetic predisposition to subclinical personality traits that mirror the positive and/or negative symptoms of schizophrenia may combine with certain developmental experiences that conspire to the development of a Cluster A personality disorder. 

Major Depressive Disorder with Psychotic Features. One severe subtype of depression is characterized by both depressive and psychotic symptoms. Unless a longitudinal history is available, it can be difficult to distinguish a patient with a psychotic depression from a depressed patient who has a comorbid Cluster A personality disorder. Some qualitative features may be helpful, but these are not wholly reliable. The most prominent psychotic symptoms of a psychotic depression tend to be delusions and auditory hallucinations, but these sometimes present in an attenuated form more reminiscent of Cluster A symptoms. 

The key to distinguishing a Cluster A personality disorder from a psychotic depression is to obtain a history of the patient prior to the acute episode of depression. This includes both the past history from medical and psychiatric records and... 

Obsessive-Compulsive Disorder (OCD). The obsessions and compulsive rituals of OCD can sometimes resemble the odd behavior of a Cluster A personality disorder. The most helpful difference may be that the rituals of OCD are ego-dystonic while the eccentricity of Cluster A personality disorder tends to be ego-syntonic. Usually, the OCD patient is aware of the excessive nature of the obsessions and wishes to be rid of them. The Cluster A patient tends to embrace the odd behavior and draw comfort from it. 

Avoidant Personality Disorder (APD) and Social Anxiety Disorder. These illnesses share the tendency toward social withdrawal and isolation with the Cluster A disorders. There is, however, a critical difference that can help make the distinction. The patient with social anxiety disorder is greatly troubled by the fact that (s)he may have so few friends or feel uncomfortable around them. (S)he would, in general, much prefer to feel more at ease in a social setting. This differs from the Cluster A personality disorders. The patient with SPD is indifferent to the fact that (s)he has few friends in fact, (s)he prefers to not have any. The patient with STPD is in a somewhat more intermediate position, feeling very anxious around others and perhaps preferring to have more friends, but also finds it easy to withdraw into a life of isolated fantasy. 

Schizotypai Personaiity Disorder (STPD). Patients with STPD most closely resemble those with schizophrenia. They have parallels to both the positive and negative symptoms of schizophrenia. Of the three Cluster A personality disorders, most medication research has been conducted in STPD though it is also quite limited. 

Clnster B includes the so-called dramatic and emotional disorders. This group is comprised of antisocial personality disorder (ASPD), borderline personality disorder (BPD), narcissistic personality disorder (NPD), and histrionic personality disorder (HPD). In each of these disorders, the person is attention seeking, is emotionally unstable, and finds it difhcnlt to conform to social norms. Unlike the odd and eccentric Cluster A patients and the anxious and withdrawn Cluster C patients, those with Cluster B personality disorders seldom escape clinical attention for very long. The disruptive nature of these personality disorders often leads them to psychiatric or legal intervention no later than their early adult life. 

Of particular interest is the gender distribution of the Cluster B personality disorders. Three out of four patients diagnosed with BPD are women. Likewise, most patients diagnosed with HPD are females as well. In contrast, ASPD is much more common among men. There has been considerable discussion as to whether these are true differences or whether they result from diagnostic biases. 

Even more emphasis has been placed on psychological and sociological theories of Cluster B personality disorders. Much of this centers on the frequent observation... 

Patients with Cluster A disorders may go unnoticed for years until some crisis leads to the need for acute psychiatric treatment. By contrast. Cluster B patients more often come with an extensive history dating back to childhood of encounters with mental health professionals, school counselors, and legal authorities. However, like other personality-disordered patients. Cluster B patients typically present for treatment when in crisis. 

Delusional Disorder and Schizotypal Personality Disorder. In onr experience, patients with BPD at times resemble those with Clnster A personality disorders or those with an Axis 1 psychotic disorder. Psychotic symptoms in the BPD patient, although intense, tend to arise in the context of some stressor and to be relatively short-lived. This usually takes the form of a brief psychotic disorder. Placing the BPD patient in a structured and supportive environment usually hastens the resolution of these psychotic symptoms. By contrast, the psychotic symptoms of a patient with a delusional disorder or a Cluster A personality disorder are long-term and potentially intractable even with antipsychotic treatment. 

Substance Use Disorder. Patients abusing alcohol or other substances may be prone to erratic behavior reminiscent of the Cluster B personality disorders. If these behaviors occur exclusively in a context of intoxication or during periods of heavy substance use, then the diagnosis of a Cluster B personality disorder is not warranted. Instead, treatment should be focused on the substance use disorder. This is not to say, however, that substance use disorders and Cluster B personality disorders cannot occur together. In fact, the difficulty that these patients have in self-soothing leaves them especially vulnerable to substance abuse. 

Of the Cluster B personality disorders, only BPD has received any significant degree of attention in terms of psychopharmacology research. However, the implications of that research as well as other studies into the treatment of nonspecific aggression may be applicable to antisocial, narcissistic, and histrionic personalities as well. 

The so-called anxious disorders of Cluster C include avoidant personality disorder (APD), dependent personality disorder (DPD), and obsessive-compulsive personality disorder (OCPD). Like the Cluster A disorders, these personality disorders are typically unobtrusive and may escape clinical detection for many years. Over time, patients adapt their life styles to these illnesses by decreasing their social contacts in an effort to minimize anxiety. In so doing, they further decrease the likelihood of encountering mental health professionals. 

Genetic studies of these disorders have focused on the likelihood that introversion is an inherited character trait. There does appear to be a considerable genetic component to introversion that in turn increases the risk of developing a Cluster C personality disorder. In addition to introversion, the obsessionality seen in OCPD also appears to have an inherited basis that may contribute to the risk of developing that disorder. 

These patients will often present with complaints of depressed mood or anxiety. The depression frequently takes the form of dysthymic disorder although these patients are at increased risk for major depressive disorder as well. Anxiety is often a symptom of the personality disorder itself, though comorbid Axis 1 anxiety disorders are occasionally present. Similar to the other personality disorders, there is a differential diagnosis that should be considered in patients who have a Cluster C personality disorder. 

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