ABSTRACT
The purpose of this chapter is to provide an overview of the decision-making dysfunctions identified in people with substance addictions, as compared with non-drug-using groups, via cognitive tasks that challenge different aspects of choice. I will specifically review empirical evidence regarding five types of cognitive tasks, related to five different aspects of decision-making: reflection impulsivity, delay discounting, decision-making under risk, decision-making under ambiguity and social decision-making. Each of these aspects has specific implications for the development and/or maintenance of addiction. Reflection impulsivity refers to the amount of information that is collected before making a decision, either in open situations or within a risk–reward trade-off scenario (i.e., gathering more information is linked to less reward). Therefore, reflection impulsivity would be relevant to making decisions that are adequately informed (e.g., pursuing knowledge about the positive/negative effects of a certain drug, or drug dosage) versus decisions made on the spur of the moment (e.g., taking whatever drug/dosage is available). Delay discounting relates to choices between lower immediate rewards and larger more delayed rewards (e.g., between $5 now and $50 in 90 days). It is specifically relevant to weighing the pros and cons of potential rewards taking into account both the present and the future. People showing high levels of delay discounting would focus on the immediate lure of drug-related reward, and would be less mindful about the long-term effects of drug use. Decision-making under risk, or risk-taking, consists of choosing between options that contain explicit information about their outcomes. Conversely, decision-making under ambiguity involves choices between options with unknown (or hardly accessible) outcomes. Decision-making under risk and ambiguity are both relevant to evaluating decision-making options in relation to their outcomes; hence, they would be implicated in conflict choices, such as drugs versus work/study the next day, or continuing drug use versus seeking treatment. Sometimes these choices will be framed in risky scenarios (e.g., the risk of choosing drugs versus school/work is explicit), but some other times they will be framed in ambiguous scenarios (e.g., treatment success is not guaranteed; taking drugs during treatment will only have negative consequences if you are caught). Finally, social decision-making is broadly defined as choices made within a social context, by virtue of the presence of others, or the need to interact with others. This aspect of decision-making is particularly 340relevant for decisions that involve other people, either during evaluation of options (e.g., peer pressure to take drugs) or during evaluation of consequences (e.g., the negative impact of drug use on loved ones). I will focus on data from validated behavioral choice measures of the above-described mechanisms (see Table 27.1 for a summary of the paradigms employed), along with neuroimaging findings that speak of the neural correlates of these mechanisms, in populations with substance addictions that are drug-abstinent at the time of testing. Therefore, the findings that I will review speak to the (non-acute) residual and/or persistent decision-making dysfunctions associated with substance use. I will start with the most highly used legal substance (i.e., alcohol), and then progress with the most frequent drugs of concern among addiction treatment settings: cannabis, stimulants and opiates. Since this sequence (i.e., alcohol, cannabis, and “hard drugs”) echoes the most typical individual trajectory of drug use from a developmental standpoint, findings concerning early onset drugs such as alcohol and cannabis will also be used to illustrate premorbid and early risk factors for decision-making dysfunctions among individuals with addiction. Although findings are mainly interpreted in relation to consumption of the above-described substances, I will also emphasize the relevance of sociodemographic, personality, and clinical factors whenever they seem relevant to interpret decision-making profiles. Ultimately, the decision-making profile of individuals with substance use disorders reflects a combination of their genetic and environmental background, their personality, the neuro-psycho-pharmacological effects of the drugs taken and the current clinical and contextual situation that they are experiencing. While case-control comparisons between people with substance addictions and non-using groups typically match the two groups in terms of socio-demographic characteristics including ancestry, age, education, socio-economic status and relevant state variables (e.g., mental health), matching for specific genetic factors or personality characteristics is incredibly challenging and thus rarely done. These complementary influences will be discussed in the concluding section.
