Addictions
June 6, 2022
Links between trauma and addictions are well-established. The association can be viewed from a lens of social construction, as well through psychological development, and biological pathways. This approach is known as the biopsychosocial model of health and disease.
This article focuses on biological mechanisms. The primary neurotransmitter associated with addictions is dopamine, which contributes to various addictions through its differentiated roles in reinforcement, motivation, and self-regulation [1]. The mesolimbic pathway transports dopamine from the ventral tegmental area to the nucleus accumbens, amygdala, and hippocampus.
In the context of addictions and trauma, three major neural systems have been identified [2]:
1) Motivational reward (the “wanting” that drives the motivation necessary to claim the reward).
2) Consummatory reward (the experience of pleasure when a reward is received).
3) Reward learning (adaption of behavior based on reward history).
Early Life Adversity and Trauma
Early experiences of trauma have a long developmental reach, resulting in reward-related neural alterations [3] with profound implications for substance-seeking behavior (including food). Individuals with post-traumatic stress disorder (PTSD) have been shown to have increased dopamine transporter density, which may reflect a higher dopamine turnover and potentiate exaggerated fear responses to cues associated with past trauma [4].
The overlaps between stress and reward neurobiology suggest that any changes in stress neurobiology are likely to influence reward [5]. It is not necessarily positive or negative reinforcement to avoid withdrawal symptoms that drive addictions, but rather the learned association of relief from an aversive mental state that drives cravings in susceptible individuals [6]. Such learned associations may be established for life, but recovery is always accessible!
Trauma results in deficits in ventral-striatum-related functions of reward responsiveness and approach motivation, particularly when the stressor is experienced in early development [5]. The ventral striatum includes the NAc and is associated with the limbic system, implicated as a critical part of decision-making in the context of reward-related behavior.
Link Between Trauma and Reward Processing
Among individuals exposed to a high degree of psychosocial stressors (including ethnic minority status and living in an urban environment), resting-state MRI showed increased corticostriatal connectivity between the ventral striatum and brain regions implicated in salience, compared to controls [7]. Salience can be understood as the assignment of value, which works with the memory to “learn” behaviors. Among children ages 9-12, MRI data suggested that trauma is associated with alterations in the brain’s sensitivity to rewards [8]. Findings suggest that the link between trauma and reward processing could be explained, in part, by differences in the ventral striatal response to rewards. We hope this information helps to connect some dots for you and your loved ones.
Impulsivity
Impulsivity refers to an individual’s propensity to have a compromised ability to engage in top-down inhibitory control in the face of reward anticipation [9]. Impulsivity is a multidimensional construct spanning several psychological domains with links to both dopamine and serotonin [10]. Key frontostriatal circuits may link multiple forms of adversity to drug use and other addiction-related behaviors.
Impulsivity has been negatively correlated with dopamine in the prefrontal cortex: higher impulsivity levels relate to lower concentrations of dopamine, which creates a positive feedback loop leading to increased impulsivity [11]. The good news is that nutrition-focused interventions that incorporate principles of mindfulness can improve impulsive behaviors.
Delay Discounting
Delay discounting is related to impulsivity and may be a consequence of brain-related changes. Delay discounting describes the process by which individuals discount temporally displaced rewards more steeply in favor of immediate rewards. It has been suggested that elevated temporal discounting rates are a predisposing factor rather than a consequence of compulsive behavior [12].
A recent meta-analysis of neuronal correlates of delay discounting found that reduced ventral striatum activity was associated with an impaired valuation process [13]. Have you been trading off long-term goals for short-term crisis management? Is it time for a new chapter?
Summary
The effect of trauma on reward sensitivity can be captured by a range of behavioral processes, but the most notable outcome is addictions. Common addictions include drugs, alcohol, nicotine, and food. Have you experienced impulsive behaviors with any of these substances?
Wise Mind Nutrition is here to help you recover from addiction-like behaviors, particularly related to highly palatable food. Identifying the origin of the addictions is just the beginning. The next step is taking action to support resilience and work toward rewiring your brain, one behavior at a time! Seeing a nutritionist for mental health can be an important first step in improving your mood and relationship with food.
References
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3. Yang R, Yu Q, Owen CE, Aspe GI, Wiggins JL (2021) Contributions of childhood abuse and neglect to reward neural substrates in adolescence. Neuroimage Clin 32:102832
4. Hoexter MQ, Fadel G, Felício AC, et al (2012) Higher striatal dopamine transporter density in PTSD: an in vivo SPECT study with [99mTc]TRODAT-1. Psychopharmacology 224:337–345
5. Novick AM, Levandowski ML, Laumann L, Philip NS, Price LH, Tyrka AR (2018) The effects of early life stress on reward processing. Journal of psychiatric research 101:80–103
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10. Jentsch DJ, Ashenhurst JR, Cervantes CM, Groman SM, James AS, Pennington ZT (2017) Dissecting impulsivity and its relationships to drug addictions. Annals of the New York Academy of Sciences 1327:1–26
11. Bosker WM, Neuner I, Shah JN (2017) The role of impulsivity in psychostimulant- and stress-induced dopamine release: Review of human imaging studies. Neuroscience & Biobehavioral Reviews 78:82–90
12. Kekic M, McClelland J, Bartholdy S, Chamali R, Campbell IC, Schmidt U (2019) Bad Things Come to Those Who Do Not Wait: Temporal Discounting Is Associated With Compulsive Overeating, Eating Disorder Psychopathology and Food Addiction. Frontiers Psychiatry 10:978
13. Schüller CB, Kuhn J, Jessen F, Hu X (2019) Neuronal correlates of delay discounting in healthy subjects and its implication for addiction: an ALE meta-analysis study. Am J Drug Alcohol Abus 1–16
