Following on from the last two days’ blogs of Can decision-making research provide a better understanding of chemical and behavioral addictions and Decision-making difficulties in gambling and eating disorders today the third and final part of this blog addresses decision making deficits in behavioral addictions of internet and sex addictions.
The main findings of this review in relation to internet and sex addictions were that internet addiction disorder is associated with risky decision making and increased choice impulsivity with corresponding discrepant activation in the dorsolateral prefrontal cortex, OFC, anterior cingulate cortex, caudate and insula. Sexual addictions are in turn associated with exaggerated impulsive choice and suggestive evidence of abnormalities in reward processing.
“Introduction of the Internet and it’s commercialization by 1990, and reaching near 2.2 billion users in 2011 opened the door to a large variety of behavioral addictions: videogame addiction, online sex addiction, online gambling, compulsive internet shopping, excessive online social networking, and emailing. Supporters are trying to bring these addictions under one umbrella called Internet Addiction Disorder (IAD), defined as an inability of the individual to control his/her Internet use with subsequent psychological, social and work difficulties [113-115].
Opponents try to differentiate an internet addiction from obsession, self-medication and compulsion or point to inconsistencies in previous studies [116]. DSM-V places Internet Use Disorder in Section III and recommends for further study [117]. Meanwhile, the prevalence of IAD is ranging from 1 % to over 15% in different populations [118-120] and continues growing, as well as the amount of evidence supporting the idea that IAD may share similar psychological and neurobiological abnormalities with other addictive disorders (for review see [121, 122]).
A pervasive finding in individuals addicted to the internet is cognitive control impairment reflected in low performance in the Gambling Task [123, 124]. Study of the impulsivity among Chinese students addicted to the internet conducted by Cao and colleagues [126] showed that Internet Addiction group had significantly higher scores on the Barratt Impulsiveness Scale and on the failure to inhibit responses of GoStop Impulsivity Paradigm with a significant positive correlation between Diagnostic Questionnaire for Internet Addiction (YDQ) scores.
At the same time internet addicted high school students tended to score lower on a measure of self-control [127]. Although authors did not consider comorbid disorders or drug use in their study, Saville and colleagues [128] were first to show that the internet addicts discounted delayed rewards faster than non-internet addicts.
Impaired decision making ability in excessive internet gamers is comparable with other forms of behavioral addiction – pathological gambling, impulse control disorder or substance abuse [129]. Study of the effect of feedback processing on decision making deficits under risk among excessive internet gamers demonstrated that they were choosing more disadvantageous options, utilized feedback less frequently, and were not able to utilize feedback to optimize their decisions [130].
Additionally, adolescents with excessive videogame play showed increased reward dependence trait, as well as high prevalence of dopamine D2 receptor Taq1A1 and low activity Catecholamine-OMethyltransferase (COMT) alleles [125]. Several neuroimaging studies also demonstrate structural and functional abnormalities in individuals with IAD similar to other chemical or behavioral addictions.
Functional brain imaging studies in internet addiction coincide in overactivation of the limbic system associated with internet related cues (for review see [121, 131]. In an early study Ko et al., showed that individuals who excessively played World of Warcraft had, compared to healthy controls, stronger activations within the nucleus accumbens, the OFC, and the caudate while watching game related pictures. These activities were also correlated positively with subjective gaming craving [132]. These findings were consistent with those in individuals in other online games [133].
When performing guessing task, internet addicts show increased activation of OFC, important for value-guided behavior, during a simulated “win” condition and decreased activation in the ACC (strongly implicated in aversive processing) during simulated “monetary loss” [134]. Measuring metabolic tissue activitiy in the different brain regions in a group of excessive internet game users via 18Ffluorodeoxyglucose positron emission tomography [135] brought suprising results. Excessive internet game users had an increased glucose metabolism in the brain regions implicated in impulse control, reward processing and somatic representation of previous experiences (right middle orbitofrontal gyrus, left caudate and right insula) and decreased glucose metabolism in the regions involved in executive function (bilateral postcentral gyrus, left precentral gyrus, and bilateral occipital regions).
Those results were expected. What was not expected was excessive internet game users increased orbitofrontal activity registered during resting state. This phenomena authors explained as “task independent mental hyperactivity and greater effort in inhibitory control associated with it”. Craving is a core symptom of addiction.
Neural substrates of cue-induced gaming urge/craving in online gaming addicts (right OFC, right nucleus accumbens, bilateral ACC and mPFC, right DLPFC and right caudate) are similar to those of the cueinduced craving in substance dependence (132). Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) study among adolescents with IAD showed morphological changes in the areas crucial for an addiction: abnormal white matter integrity in OFC, corpus callosum, cingulum, internal and external capsules and decreased gray matter volume in DLPFC, the supplementary motor area, the OFC and the cerebellum [119, 136].
Both white and gray matter changes strongly correlated with the duration of the internet addiction. Lastly, a considerable amount of internet addiction research has targeted subjects with Internet Gaming Disorder (IGD) [131]. Dong and Potenza have proposed a three domain cognitive-behavioral model for conceptualizing IGD, which comprise motivational drives related to reward seeking and stress-reduction, behavioral control relating to executive inhibition, and decision-making that involves weighing the pros and cons of engaging in motivated behaviors [122].
Sexual Addiction
Sexual addiction may include excessive masturbation, viewing pornography, cybersex, and empty affairs. Reaching up to 6% in its prevalence, this behavioral addiction remains as controversial in term of the diagnosis as it was decades ago. Unlike IAD, sexual addiction was not considered even under Section III in DSM-V, meaning much more research is required. Despite differences between hypothesis and diagnostic criteria proposed by Goodman (137) or Coleman and colleagues [138] (for review also see [139]) they all point to maladaptive pattern of behavior with recurrent failure to control it and continuation of the behavior despite harmful consequences.
Logue [140] pointed to unsafe sexual behavior as being directly related to a tendency to choose short-term rewards (sexual gratification) in spite of potential long-term consequences (disease, unwanted pregnancy). While money discounting provides important information regarding patterns of impulsive choice, there is a growing amount of data supporting the use of stimulus-specific outcomes to study decision-making behavior as well.
Lawyer and colleagues [141] showed that delay and probability discounting for hypothetical sexual activity resembled patterns similar for money among healthy college students. Adult “erotica-users” discounted the value of erotica similarly to money, while healthy controls did not [141]. Delay was proved to be a critical variable strongly related to sexual risk behavior among HIV-affected individuals with cocaine dependence during the Sexual Discounting Task [142].
Regarding brain pathways regulating sexual behavior, neuroimaging studies corroborated that amygdala, mesencephalic tegmentum, and the septal nuclei are activited during sexual response [143]. Prefrontal lesions and bilateral lesions of the temporal lobe regions are associated with hypersexuality and disinhibition [144].
Psychometric measures of impulsivity and compulsive sexual behavior, the go/no-go task, indicated that patients with compulsive sexual behavior were significantly more impulsive than controls. The same patients showed significantly higher superior frontal region mean diffusivity (MD) than controls [145].
Whole brain structural MRI in pedophile patients showed decreased gray matter volume in the ventral striatum, the OFC and the cerebellum, findings which were almost identical to those in cocaine, methamphetamine and obesity studies [146]. This study also demonstrated for the first time that sexual addiction can cause physical, anatomic change in the brain – the hallmark of addiction.
Other conditions such as video games addiction [147] or compulsive or pathological buying [148] are also being considered as behavioral addictions. However, we have not included them in this review because of lack of consensus in the literature or limited findings regarding associated decision making processes.
POSSIBLE INTERVENTIONS
Overall, careful characterization of patients may allow to identify subsets of individuals who may benefit from specific interventions addressing craving, homoeostatic deviations, or more targeted cognitive interventions [11]. There are already successful therapeutic approaches focused on improving cognition and decision making capabilities of psychiatric patients: cognitive remediation and variations of cognitive behavior therapy which aim to enhance emotional cognitive control and decision making skills. Cognitive remediation is based on enhancing specific cognitive processes in order to modify the course and morbidities of disease.
Recent advances in cognitive remediation strategies and delivery methods have notably increased the success of this intervention [149]. Successful examples are found in areas as diverse as schizophrenia [150], bipolar disorder [151], ADHD [152], dyslexia [153], traumatic brain injury [154] stroke [155], and anorexia nervosa [156].
Improvement in executive function and clinical outcomes following cognitive remediation correlate with discrete changes in neural activity [157], non-effortful auditory evoked potentials [158], peripheral biomarkers as brain derived neurotrophic factor (BDNF) [159], as well as, improvements in everyday functioning. Within the scope of this review, cognitive remediation has proven beneficial in improving in choice impulsivity among stimulant addicts [66] and weight, depression, visiospatial memory, perceptual disembedding abilities, and verbal fluency in adolescents suffering with anorexia nervosa [156].
Furthermore, the promising results of cognitive enhancing agents, such as galantamine, modafinil, atomoxetine, methylphenidate, and guanfacine, warrant further research about their potential as therapeutic agents for addiction [160].
CONCLUSION
The confluence of several disciplines studying the mind and how the brain makes decisions may provide an better understanding of common mental processes (decisionmaking) to chemical and behavioral addictions. The study of three distinct constructs, cognitive control, reward and impulsivity, has shed light on our understanding of addiction. Accordingly, available brain imaging studies show consistent abnormalities in frontoparietal regions and limbic system function. Utilization of additional paradigms can further lead to interventions to address everyday situations that patients with addiction and other mental illness face. Consideration of decision making patterns in the assessment and management of patients with addictive disorders might yield evidence-based interventions with real life impact such as cognitive remediation.
Reference
Inside The Alcoholic Brain 