Psychological dependence

Summary

Psychological dependence is a cognitive disorder that involves emotional–motivational withdrawal symptoms – such as anxiety or anhedonia – upon cessation of prolonged drug abuse or certain repetitive behaviors.[4] It develops through frequent exposure to certain psychoactive substances or behaviors, which leads to an individual requiring further exposure to avoid withdrawal symptoms, as a result of negative reinforcement. Neuronal counter-adaptation is believed to play a role in generating withdrawal symptoms, which could be mediated through changes in neurotransmitter activity or altered receptor expression.[5][6][7][8][9] Environmental enrichment and physical activity can attenuate withdrawal symptoms.[10][11]

Addiction and dependence glossary[1][2][3]
  • addiction – a biopsychosocial disorder characterized by persistent use of drugs (including alcohol) despite substantial harm and adverse consequences
  • addictive drug – psychoactive substances that with repeated use are associated with significantly higher rates of substance use disorders, due in large part to the drug's effect on brain reward systems
  • dependence – an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)
  • drug sensitization or reverse tolerance – the escalating effect of a drug resulting from repeated administration at a given dose
  • drug withdrawal – symptoms that occur upon cessation of repeated drug use
  • physical dependence – dependence that involves persistent physical–somatic withdrawal symptoms (e.g., fatigue and delirium tremens)
  • psychological dependence – dependence socially seen as being extremely mild compared to physical dependence (e.g., with enough willpower it could be overcome)
  • reinforcing stimuli – stimuli that increase the probability of repeating behaviors paired with them
  • rewarding stimuli – stimuli that the brain interprets as intrinsically positive and desirable or as something to approach
  • sensitization – an amplified response to a stimulus resulting from repeated exposure to it
  • substance use disorder – a condition in which the use of substances leads to clinically and functionally significant impairment or distress
  • tolerance – the diminishing effect of a drug resulting from repeated administration at a given dose

Symptoms edit

Symptoms of psychological dependence include:

Development edit

Psychological dependence develops through consistent and frequent exposure to drug or behavioral activity.[12] After sufficient exposure to a stimulus capable of inducing psychological dependence (e.g., drug use), an adaptive state develops and results in the onset of withdrawal symptoms that negatively affect cognition upon disengagement.[4]

Psychostimulants, such as amphetamine or cocaine, are an example of a drug class where only emotional and motivational (i.e., cognitive) symptoms are observed in withdrawal, as opposed to somatic withdrawal in cases of physical dependence.[4] Whilst psychological dependence is often associated with effects of drug use, a behavioral dependence-withdrawal syndrome is possible. For example, exercise dependence can develop in amateur and professional athletes whereby marked cognitive withdrawal symptoms - associated with depressive symptoms and increased anxiety - are experienced when abstaining from experience for two weeks or longer.[13]

The mechanism that generates dependence involves a neuronal counter-adaptation, which is localized to areas of the brain responsible for a drug's positive reinforcement. This adaptation occurs as a change in neurotransmitter activity or in receptor expression.[5]

Biomolecular mechanisms edit

Two factors have been identified as playing pivotal roles in psychological dependence: the neuropeptide "corticotropin-releasing factor" (CRF) and the gene transcription factor "cAMP response element binding protein" (CREB).[1] The nucleus accumbens (NAcc) is one brain structure that has been implicated in the psychological component of drug dependence. In the NAcc, CREB is activated by cyclic adenosine monophosphate (cAMP) immediately after a high and triggers changes in gene expression that affect proteins such as dynorphin; dynorphin peptides reduce dopamine release into the NAcc by temporarily inhibiting the reward pathway. A sustained activation of CREB thus forces a larger dose to be taken to reach the same effect. In addition, it leaves the user feeling generally depressed and dissatisfied, and unable to find pleasure in previously enjoyable activities, often leading to a return to the drug for another dose.[14]

In addition to CREB, it is hypothesized that stress mechanisms play a role in dependence. Koob and Kreek have hypothesized that during drug use, CRF activates the hypothalamic–pituitary–adrenal axis (HPA axis) and other stress systems in the extended amygdala. This activation influences the dysregulated emotional state associated with psychological dependence. They found that as drug use escalates, so does the presence of CRF in human cerebrospinal fluid. In rat models, the separate use of CRF inhibitors and CRF receptor antagonists both decreased self-administration of the drug of study. Other studies in this review showed dysregulation of other neuropeptides that affect the HPA axis, including enkephalin which is an endogenous opioid peptide that regulates pain. It also appears that µ-opioid receptors, which enkephalin acts upon, is influential in the reward system and can regulate the expression of stress hormones.[15]

Increased expression of AMPA receptors in nucleus accumbens MSNs is a potential mechanism of aversion produced by drug withdrawal.[16]

Change in neurotransmitter activity

Studies have shown that in rats experiencing ethanol withdrawal, stimulant withdrawal or opioid withdrawal, the nucleus accumbens shows lower levels of serotonin and dopamine than controls. These decreases are associated with depression and anxiety.[6][7]

In anatomically distinct areas of the rat brain, withdrawal is linked to lower levels of GABA and neuropeptide Y as well as higher levels of dynorphin, corticotropin-releasing factor, and norepinephrine; these fluctuations can contribute to psychological dependence.[5]

Altered receptor expression

Changes in receptor expression have also been linked to various symptoms of drug withdrawal. For example, in a study of rats undergoing nicotine withdrawal there has been observed a down regulation of α6β2*n-icotinic acetylcholine receptors in the mesostriatal dopaminergic pathways.[8]

Methods for reducing dependence edit

A study examined how rats experienced morphine withdrawal in different surroundings. The rats were either placed in a standard environment (SE) or in an enriched environment (EE). The study concluded that EE reduced depression and anxiety withdrawal symptoms.[10]

Another study tested whether swimming exercises affected the intensity of perceivable psychological symptoms in rodents during morphine withdrawal. It concluded that the anxious and depressive states of the withdrawal were reduced in rats from the exercise group.[11]

Distinction between psychological and physical dependence edit

Table 1: List of different drugs and which type of dependence they induce[17]
Physical dependence Psychological dependence
Alcohols SSRIs
Opioids Hallucinogens
Barbiturates Inhalants
Benzodiazepines
Stimulants
Cannabis products

The major differences between psychological dependence and physical dependence are the symptoms they cause. While symptoms of psychological dependence relate to emotional and motivational impairment, physical dependence entails somatic symptoms e.g. increased heart rate, sweating, tremor. The type of dependence experienced after chronic use varies between different substances (see table 1).[17]

Although psychological dependence and physical dependence are distinct entities, they should not be characterized as mutually exclusive. Empirical studies have shown that cravings, which are traditionally associated with psychological dependence, involve a physiological element.[17][18]

See also edit

References edit

  1. ^ a b Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 15: Reinforcement and Addictive Disorders". In Sydor A, Brown RY (eds.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 364–375. ISBN 9780071481274.
  2. ^ Nestler EJ (December 2013). "Cellular basis of memory for addiction". Dialogues in Clinical Neuroscience. 15 (4): 431–443. PMC 3898681. PMID 24459410. Despite the importance of numerous psychosocial factors, at its core, drug addiction involves a biological process: the ability of repeated exposure to a drug of abuse to induce changes in a vulnerable brain that drive the compulsive seeking and taking of drugs, and loss of control over drug use, that define a state of addiction. ... A large body of literature has demonstrated that such ΔFosB induction in D1-type [nucleus accumbens] neurons increases an animal's sensitivity to drug as well as natural rewards and promotes drug self-administration, presumably through a process of positive reinforcement ... Another ΔFosB target is cFos: as ΔFosB accumulates with repeated drug exposure it represses c-Fos and contributes to the molecular switch whereby ΔFosB is selectively induced in the chronic drug-treated state.41. ... Moreover, there is increasing evidence that, despite a range of genetic risks for addiction across the population, exposure to sufficiently high doses of a drug for long periods of time can transform someone who has relatively lower genetic loading into an addict.
  3. ^ Volkow ND, Koob GF, McLellan AT (January 2016). "Neurobiologic Advances from the Brain Disease Model of Addiction". New England Journal of Medicine. 374 (4): 363–371. doi:10.1056/NEJMra1511480. PMC 6135257. PMID 26816013. Substance-use disorder: A diagnostic term in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) referring to recurrent use of alcohol or other drugs that causes clinically and functionally significant impairment, such as health problems, disability, and failure to meet major responsibilities at work, school, or home. Depending on the level of severity, this disorder is classified as mild, moderate, or severe.
    Addiction: A term used to indicate the most severe, chronic stage of substance-use disorder, in which there is a substantial loss of self-control, as indicated by compulsive drug taking despite the desire to stop taking the drug. In the DSM-5, the term addiction is synonymous with the classification of severe substance-use disorder.
  4. ^ a b c Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 15: Reinforcement and Addictive Disorders". Molecular neuropharmacology: a foundation for clinical neuroscience (2nd ed.). New York, NY: McGraw-Hill Medical. pp. 364–368. ISBN 9780071481274. The defining feature of addiction is compulsive, out-of-control drug use, despite negative consequences. ...
    Addictive drugs are both rewarding and reinforcing. ... Familiar pharmacologic terms such as tolerance, dependence, and sensitization are useful in describing some of the time-dependent processes that underlie addiction. ...
    Dependence is defined as an adaptive state that develops in response to repeated drug administration, and is unmasked during withdrawal, which occurs when drug taking stops. Dependence from long-term drug use may have both a somatic component, manifested by physical symptoms, and an emotional–motivation component, manifested by dysphoria. While physical dependence and withdrawal occur with some drugs of abuse (opiates, ethanol), these phenomena are not useful in the diagnosis of addiction because they do not occur with other drugs of abuse (cocaine, amphetamine) and can occur with many drugs that are not abused (propranolol, clonidine).

    The official diagnosis of drug addiction by the Diagnostic and Statistic Manual of Mental Disorders (2000), which makes distinctions between drug use, abuse, and substance dependence, is flawed. First, diagnosis of drug use versus abuse can be arbitrary and reflect cultural norms, not medical phenomena. Second, the term substance dependence implies that dependence is the primary pharmacologic phenomenon underlying addiction, which is likely not true, as tolerance, sensitization, and learning and memory also play central roles. It is ironic and unfortunate that the Manual avoids use of the term addiction, which provides the best description of the clinical syndrome.
  5. ^ a b c d Koob, George F.; Le Moal, Michel (2008). "Addiction and the brain antireward system". Annual Review of Psychology. 59: 29–53. doi:10.1146/annurev.psych.59.103006.093548. ISSN 0066-4308. PMID 18154498.
  6. ^ a b Diana, M; Pistis, M; Carboni, S; Gessa, G L; Rossetti, Z L (1993-09-01). "Profound decrement of mesolimbic dopaminergic neuronal activity during ethanol withdrawal syndrome in rats: electrophysiological and biochemical evidence". Proceedings of the National Academy of Sciences of the United States of America. 90 (17): 7966–7969. Bibcode:1993PNAS...90.7966D. doi:10.1073/pnas.90.17.7966. ISSN 0027-8424. PMC 47268. PMID 8367449.
  7. ^ a b Parsons, L. H.; Koob, G. F.; Weiss, F. (1995). "Serotonin dysfunction in the nucleus accumbens of rats during withdrawal after unlimited access to intravenous cocaine". The Journal of Pharmacology and Experimental Therapeutics. 274 (3): 1182–1191. ISSN 0022-3565. PMID 7562486.
  8. ^ a b Mugnaini, M.; Garzotti, M.; Sartori, I.; Pilla, M.; Repeto, P.; Heidbreder, C. A.; Tessari, M. (2006). "Selective down-regulation of [(125)I]Y0-alpha-conotoxin MII binding in rat mesostriatal dopamine pathway following continuous infusion of nicotine". Neuroscience. 137 (2): 565–572. doi:10.1016/j.neuroscience.2005.09.008. ISSN 0306-4522. PMID 16289885. S2CID 26730060.
  9. ^ Yoneda, Yukio (2005). "Functional Proteins Involved in Regulation of Intracellular Ca2+ for Drug Development: Preface". Journal of Pharmacological Sciences. 97 (3): 337–338. doi:10.1254/jphs.fmj04007x1. ISSN 1347-8613.
  10. ^ a b Hammami-Abrand Abadi, Arezoo; Miladi-Gorji, Hossein; Bigdeli, Imanollah (April 2016). "Effect of environmental enrichment on physical and psychological dependence signs and voluntary morphine consumption in morphine-dependent and morphine-withdrawn rats". Behavioural Pharmacology. 27 (2 and 3 - Special Issue): 270–278. doi:10.1097/fbp.0000000000000197. ISSN 0955-8810. PMID 26397757. S2CID 11212134.
  11. ^ a b Fadaei, Atefeh; Gorji, Hossein Miladi; Hosseini, Shahrokh Makvand (2015-01-15). "Swimming reduces the severity of physical and psychological dependence and voluntary morphine consumption in morphine dependent rats". European Journal of Pharmacology. 747: 88–95. doi:10.1016/j.ejphar.2014.11.042. ISSN 1879-0712. PMID 25498794.
  12. ^ "Understanding Tolerance, Dependence, and Addiction". DrugAbuse.com. 2016-06-29. Retrieved 2019-02-23.
  13. ^ Weinstein AA, Koehmstedt C, Kop WJ (November 2017). "Mental health consequences of exercise withdrawal: A systematic review". General Hospital Psychiatry. 49: 11–18. doi:10.1016/j.genhosppsych.2017.06.001. ISSN 1873-7714. PMID 28625704. Results showed a consistent pattern for adverse effects of exercise withdrawal on these mental health measures, particularly depressive symptoms and anxiety. For the studies reviewed, depressive symptoms consistently occurred following the cessation of exercise. Depressive symptoms includes a variety of complaints, including fatigue, tension, confusion, lower self-esteem, insomnia, and irritability [25,27,28,36]. However, the severity of these symptoms did not reach the level of a clinical diagnosis. Exercise deprivation also consistently resulted in an increase in general anxiety (state anxiety) [24,26,32,33], but no information was provided regarding anxiety disorders based on clinical diagnostic criteria. Regarding general mood symptoms and general well-being, results indicated consistent negative changes in both general mood and wellbeing [21,22,24–28,31–37]. The most frequently reported feelings were guilt, irritability, anger, confusion, restlessness, tension, frustration, stress, and sluggishness (loss of vigor).
  14. ^ AJ Giannini, RQ Quinones, DM Martin. Role of beta-endorphin and cAMP in addiction and mania. Society for Neuroscience Abstracts. 15:149, 1998.
  15. ^ Koob G, Kreek MJ (August 2007). "Stress, dysregulation of drug reward pathways, and the transition to drug dependence". The American Journal of Psychiatry. 164 (8): 1149–59. doi:10.1176/appi.ajp.2007.05030503. PMC 2837343. PMID 17671276.
  16. ^ Carlezon WA, Thomas MJ (2009). "Biological substrates of reward and aversion: a nucleus accumbens activity hypothesis". Neuropharmacology. 56 (Suppl 1): 122–32. doi:10.1016/j.neuropharm.2008.06.075. PMC 2635333. PMID 18675281.
  17. ^ a b c "What is pshychological dependence?". 2018-10-29.
  18. ^ De Masi, Franco (2016). "Le concept de pulsion de mort est-il encore utile en clinique ?". L'Année Psychanalytique Internationale. 2016 (1): 157–173. doi:10.3917/lapsy.161.0157. ISSN 1661-8009.