«by Amy Lynn Byrd, Ph.D. B.S. in Psychology, College of Charleston, 2006 M.S. in Clinical Psychology, University of Pittsburgh, 2010 Submitted to the ...»
developmental considerations relevant to the current dissertation are highlighted. This dissertation will then offer a rationale for the utility of examining the basic neural circuitry associated with reward and punishment processing and review emerging neuroimaging work that demonstrates abnormalities in youth with CP. Finally, research on treatment of CP in youth will be presented, highlighting the proposed contribution of reward and punishment processing and how abnormalities within this domain may impact the effectiveness of intervention. Following the presentation of background information, Chapter 3 provides the details of study design, methods, and analytic strategy utilized to examine the proposed hypotheses. Chapter 4 provides the aim specific results and a brief summary of the findings. Finally, a general discussion, implications and future directions are presented in Chapter 5.
CP refers to a set of problematic behaviors encompassed within the diagnostic categories of oppositional-defiant disorder (ODD) and conduct disorder (CD) set forth in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5; American Psychiatric Association, 2013). Symptoms associated with ODD reflect a recurrent pattern of behaviors that tend to be irritable and defiant in nature while CD is associated with a more severe cluster of behaviors such as aggression towards people and animals, destruction of property, deceitfulness or theft, and status offenses. Prevalence estimates for CP peak higher than 10% across childhood and adolescence (Hinshaw & Lee, 2003; Maughan, Rowe, Messer, Goodman, & Meltzer, 2004), with CP representing one of the most common reasons youth are referred for mental health
behaviors to increased risk of persistent CP throughout childhood and adolescence as well as serious antisocial and delinquent behavior in adulthood (Broidy, et al., 2003; Byrd, Loeber, & Pardini, 2012; Loeber, Farrington, Stouthamer-Loeber, Moffitt, & Caspi, 1998). While many youth desist from these behaviors over time, there is consistent evidence to suggest that a small proportion of those children demonstrating early CP will show persistent levels throughout development (Broidy, et al., 2003; Loeber, et al., 1998).
Given the noted heterogeneity that exists among youth exhibiting CP (Frick & White,
2008) researchers have proposed various subtyping schemes in hopes of demarcating a more homogenous subgroup of youth at risk for exhibiting severe and chronic CP. One of the most prominent subtyping distinctions is based on research suggesting that early (i.e., childhood) versus late (i.e., adolescent) onset of CP is associated with a prolonged, stable course of problem behaviors (Moffitt, 1993). More recently, considerable focus has been directed toward the presence of psychopathic features in youth, particularly CU traits, as research has consistently shown these characteristics to be associated with severe and protracted CP (Byrd, et al., 2012;
Frick & White, 2008; Lynam, Caspi, Moffitt, Loeber, & Stouthamer-Loeber, 2007; Pardini & Loeber, 2008). While psychopathic features are defined as a constellation of interpersonal (e.g., manipulative or deceitful), emotional (e.g., callous, lacking guilt) and behavioral (e.g., impulsive) deficits, CU traits are circumscribed to the emotional dimension and include a lack of empathy, deficient guilt and remorse, and shallow affect. CU traits are of particular relevance because, until recently, they were not adequately represented among definitions of CP. In response to extensive research in this area, the DSM-5 added a 4-item specifier (i.e., ‘with limited prosocial emotions’; American Psychiatric Association, 2013) based on the presence of
thought to be indicative of distinct causal processes characterized by a unique neurobiology that lead to a heightened proclivity for persistent CP (Dadds, Fraser, Frost, & Hawes, 2005; Frick, Bodin, & Barry, 2000; Pardini, 2006). Theoretical and empirical work suggests that one potential etiological pathway may be related to a reward dominant response style and deficient punishment processing that increases risk for early and protracted CP (Frick, et al., 2003; Frick & Marsee, 2006; Pardini, 2006). Therefore, examining whether abnormalities in the neural response to reward/punishment are most pronounced in a subgroup of youth with childhoodonset CP and CU traits may be particularly informative.
However, it should be noted that, to date, there has been substantial variability in the measurement of these characteristics across studies, with many researchers assessing total psychopathic features, defined broadly as a constellation of interpersonal, affective and behavioral characteristics, and few focusing specifically on the presence of CU traits. Moreover, there have been no studies in this area to examine these features using criteria set forth in the DSM-5 ‘limited prosocial emotions’ specifier (American Psychiatric Association, 2013). Given this lack of a ‘gold standard’ with regard to measurement, distinctions between assessments of CU traits versus total psychopathic features are highlighted throughout the review of the literature. Thus, despite theoretical conjecture, it remains unclear whether the presence of CU traits, in particular, or psychopathic features, broadly defined, are associated with abnormalities in reward/punishment processing. This limitation is addressed directly in the current dissertation.
The processing of reward and punishment has profound implications for associative and contingency learning, which serves as the foundation for many aspects of behavioral, social and emotional development (Akers 1998; Kochanska 1994). From a behavioral perspective, rewards can be considered any stimulus that acts as a reinforcer and increases the likelihood of that behavior recurring in the future; conversely, punishment is conceptualized as any stimulus that decreases the likelihood of that behavior recurring in the future (Skinner, 1969). Classical and operant conditioning are two fundamental models of learning that provide a framework for understanding how aberrant reward/punishment processing may give rise to the development and persistence of CP in youth.
Classical conditioning involves learned associations between reflexive responses and antecedent stimuli or events (Pavlov, 1927). Many researchers have applied models of classical conditioning to the engagement in and persistence of CP (e.g., Damasio, 1994; Kochanska, 1994). Overall, these theoretical models emphasize the importance of reflexive emotional responses to punishment and suggest that individual differences in sensitivity to these cues may have cascading effects that ultimately increase the likelihood of engaging in CP. For example, Kochanska (1994) emphasized the role of classical conditioning in conscience development, suggesting that the internalization of social norms is facilitated by the negative emotional arousal a child experiences when being disciplined or punished for wrongdoing. Eventually this emotional arousal becomes paired with the act of wrongdoing and through repeated disciplinary interactions, youth likely become conditioned to experience increases in negative arousal when contemplating or engaging in misconduct. Importantly, this occurs even in the absence of an authority figure and is a key feature of guilt and remorse. Youth who are particularly insensitive
relatively little negative emotion when punished for rule breaking behavior and thus fail to establish conditioned associations between disciplinary interactions and emotional arousal. These youth may be less likely to encode parental messages about the acceptability of behaviors, which could hinder the internalization of moral beliefs that guide prosocial behavior. Research suggests that punishment insensitivity is linked to reduced concern for the suffering of others (Young, Fox, & Zahn-Waxler, 1999) and less guilt following transgressions (Rothbart, Ahadi, & Hershey, 1994), characteristics that increase the likelihood that one will engage in CP. Along these lines, Blair (2004; 2005) proposed that CP youth, particularly those with psychopathic features, fail to encode the emotional components of reward and punishment and are thus, unable to acquire conditioned associations. For example, distress cues in others, such as sad or fearful expressions that occur following an act of their own wrongdoing, fail to elicit negative emotional arousal and in turn impede the acquisition of important affective associations. This is believed to have downstream consequences and hinders the development of empathy and remorse, resulting in a heightened risk for engagement and persistence of CP.
Operant conditioning refers to the learning and modification of non-reflexive, voluntary behaviors through contingent stimuli or feedback (i.e., reward/reinforcement or punishment). It is founded on the principle that behaviors that are reinforced or rewarded are strengthened and perpetuated while punished behaviors are weakened and diminished (Skinner, 1969). Social learning theories of CP rely heavily on operant principles, suggesting that parents may unintentionally reinforce CP while simultaneously failing to reinforce prosocial behaviors (Patterson, et al., 1992). Patterson and colleagues (1992) focused on a coercive cycle that exists in parent-child interactions, whereby parents respond to CP with inconsistent and harsh
over time. Accordingly, a central component of parenting interventions is to break this coercive cycle by shifting behavioral contingencies and teaching parents to positively reinforce prosocial behaviors, while setting clear and consistent consequences for disruptive behaviors (Kazdin, 2003; Serketich & Dumas, 1996). It is possible that these negative parenting behaviors, such as harsh and inconsistent discipline, may be particularly detrimental for youth with deficits in reward/punishment processing and could serve to exacerbate CP (see Dadds & Salmon, 2003;
Matthys, Vanderschuren, Schutter, & Lochman, 2012b). Moreover, social learning theorists have also explored ways in which peers function to reinforce and perpetuate CP (i.e., deviancy training; Dishion, Spracklen, Andrews, & Patterson, 1996; Patterson, Dishion, & Yoerger, 2000).
Specifically, association with deviant peers has been consistently linked to higher levels of risk taking and CP over time (Rusby, Forrester, Biglan, & Metzler, 2005). The presence of deviant social influences may be particularly prominent for those youth with a reward dominant response-style and decreased sensitivity to punishment and these deficits may make youth more vulnerable to negative social influences.
2.3 REWARD AND PUNISHMENT PROCESSING IN YOUTH WITH CP:
Gray’s (1975, 1981, 1987) Reinforcement Sensitivity Theory provides one of the most cited frameworks for the study of reward and punishment processing. Historically, reward and punishment processing has been conceptualized in terms of the Behavioral Approach System (BAS) and the Behavioral Inhibition System (BIS1981, 1987). These systems serve to enhance
initiate subsequent behavioral responses. Drawing almost exclusively on basic animal learning models, Gray proposed that BAS activity reflected activation in the mesocorticolimbic circuit, while BIS functioning was linked to the septohippocampal system (Gray, 1982). Specifically, the BAS serves to increase activity and initiate goal-directed behavior in response to conditioned signals of reward, while the BIS functions to inhibit goal-directed action and avoid negative, painful, or threatening outcomes in the presence of conditioned aversive stimuli or punishment.
Gray (1981, 1987) viewed variations in the functioning of the BAS as an index of reward sensitivity, with heightened levels of BAS activation resulting in increased propensity to engage in reward-directed behavior. BIS responsivity was conceptualized as an index of punishment sensitivity, with heightened activation manifesting behaviorally as increased avoidance and a greater propensity to anxiety. Conversely, lower BIS activation is thought to be associated with insensitivity to punishment and/or threat, leading to increased reward seeking behaviors.
Extensions and modifications of this theory have focused on associations between CP and primary deficits in one or both of these systems. Quay (1988, 1993) was the first to extend Gray’s (1981, 1987) theory to manifestations of CP in youth, suggesting that these behaviors stem from a hyperactive reward system (BAS). Specifically, Quay (1988, 1993) proposed that the excessive BAS activity in antisocial youth results in a reward dominant response style that predominates the BIS and leads to persistent approach or reward-seeking behaviors. Others proposed that CP instead reflects an inherently hypoactive reward system that necessitates excessive sensation seeking (Cloninger, 1987; Zuckerman, 1996). This theory suggests that a chronically underactive reward system represents an aversive physiological state, requiring
alleviate an unpleasant internal condition.
In contrast to a central focus on reward, researchers have also posited a primary deficit in punishment processing, where CP is reflective of a hypoactive inhibition system and reduced sensitivity to cues of punishment (Eysenck, 1977; Fowles, 1980; Lykken, 1995; Patrick, 1994).
This theory suggests that individuals with reduced BIS functioning fail to experience negative arousal in response to punishment and/or fail to pair this response with behaviors or cues that result in punishment. As a result, they demonstrate difficulties inhibiting reward-seeking behaviors, due primarily to a notable reduction in conditioned fear/anxiety to punishment.