Wednesday, March 6, 2013

Tridimensional Personality Theory Psychology: Reward Dependence

From yee Wiki:

Reward dependence is characterized as a tendency to respond markedly to signals of reward, particularly to verbal signals of social approval, social support, and sentiment, and learning to maintain and pursue behaviors which were previously associated with such rewards. When reward dependence levels deviate from normal we see the rise of several personality and addictive disorders.

In psychology, reward dependence is considered a moderately heritable personality trait which is stable throughout our lives. It is an inherited neurophysiological mechanism that drives our perception of our society and the environment. Even though we are born with these personality traits, their expression during our life span can be modulated throughout our development.

Origin and definitions

Reward dependence is one of the temperament dimensions from the “tridimensional personality theory”, which was proposed by C. Robert Cloninger as part of his “unified bio-social theory of personality.”

His personality theory suggested the hypothesis that specific neurochemical transmitters in our brain determine how we respond to a specific stimulus we may experience.

These innate personality traits can play a significant role not only in an individuals' predisposition to certain disorders, but also in their maintenance of those disorders.

By understanding the specific temperamental traits that are common among individuals with specific disorders, clinicians can form a more targeted, informed approach to treatment and look to newer psychotherapies for guidance.

The relationship between temperament and individual clusters of DSM personality disorders is often investigated. According to the DSM-IV, the tridimensional structure allows up to nine major personality disorders to be identified, the theory thereby making a great contribution to the understanding of psychiatric disorders.

Relationship to personality disorders

Social reward dependence is hypothesized to be related to behaviors that represent the RD personality dimension sub-scales of social sensitivity and attachment. It is suggested that the brain substrates that are involved in the response to simple primary rewards stimuli are also implicated in the response to complex social rewards stimuli.

The RD sub-scale from the TCI inventory measures how sensitive individuals are to social rewards. High RD scores on the test correlate to increased attachment and an increased need for social relationships. Low RD scores show a movement towards social detachment and insensitivity.

According to Cloninger’s model, the early life onset of neuropsychiatric disorders lead to personality disorders, with individuals having low RD scores. Antisocial Personality Disorder (ASPD) is characterized in behavioral terms by childhood or adolescent onset of recurrent antisocial behavior.

Cloninger had predicted from his biosocial theory that individuals most at risk of aggressive, antisocial behavior, will be those with lower RD scores and these individuals are equated with the primary psychopaths who show aloofness and social detachment.

 Particular research conducted on childhood behavior has tested this theory and researchers have shown that children with lower RD scores have more of an anti-social profile as defined in the DSM, and are at highest risk for early onset of frequent delinquent behavior.

When Reward Dependence goes wrong

Lower scores of RD were also seen in Obsessional Personality, Attention Deficit Hyperactivity Disorder (ADHD) and in Borderline Personality Disorder (BPD) individuals, who exhibit symptoms leading to self-harm due to social detachment and feelings of rejection, whereas higher scores of RD were shown in Histrionic Personality Disorder (HPD) and Dependent Personality Disorder individuals who exhibit behavioral instability and poor emotional control.

Studies in autistic disorder and Asperger syndrome have shown results, where lower oxytocin levels and lower RD scores were reported in these children leading to their abnormal social behaviors. The direction of the effect i.e. whether reduced oxytocin leads to decreased affiliation or vice versa has not been clearly established. Recent animal studies would, however, suggest that changes to oxytocin lead to changes in behavior.

Also a significant positive correlation between plasma oxytocin levels and RD personality dimension was found by researchers in New Zealand.

Considerable evidence from animal studies has shown oxytocin to be involved in the processing of
social information and the regulation of social affiliative behavior.

Results from studies measuring plasma oxytocin levels in patients with a diagnosis of major depressive episode according to DSM III-R has shown decreased oxytocin levels in these patients and lower RD scores on the TCI, leading to an assumption that lower reward dependence leads to depression.

Lower RD scores and decreased plasma oxytocin levels have also typically been associated with paranoid, schizoid and schizotypal personality disorders.

In another study conducted with patients with Above-normal Plasma Vasopression (AVP) depression, it was found that these patients had lower RD scores than controls and other patients with depression disorders.  In this case a directional relationship was found in which the low reward dependence is a state-dependent characteristic of patients with AVP depression, and not vice versa.

Research has also found a low expression of reward dependence in suicide attempters. These findings and the negative correlation between reward dependence and the number of suicide attempts may suggest the implication of the noradrenergic pathway in suicide behaviors. Low scores of RD have also been implicated in showing criminality in adult age.

At the 2010 Annual meeting of the American Psychological Association (APA), a study looking at treatment methods of personality disorders was presented in which it was found, that panic disorder patients with higher RD scores were more resistant to Escitalopram treatment.

Since long-term pharmacotherapy is needed for treatment of panic disorder, the present results suggest that development of therapeutic strategy for panic patients with high reward dependence is needed.

Other clinical disorders

In response to a lack of social reward, individuals with high reward dependence are more likely to have increased noradrinergic activity.

These individuals experience feelings of depression, agitation and extreme discontent, leading them to indulge in habits that reinforce reward-seeking, such as increased sexual activity or overeating.

Individuals with higher reward dependence also look for more social approval, and are more inclined to succumb to peer-pressure. They often become overly concerned with their body image and maybe prone to eating disorders, such as Bulimia nervosa. Whereas restricting anorexia, in particular, tends to reflect low reward dependence.

Reward dependence is not consistently associated with diagnosis but can also significantly affect treatment issues, such as Therapeutic alliance.

Persistence in completing weight-loss programs were related to high RD scores during pre-treatment. This demonstrates that, having higher reward dependence enhances an individual's disposition to being more dedicated and sociable, making them increasingly respond to societal pressures, thereby reducing their risk of dropping out from weight-loss programs.

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