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Psychopharmacology is the scientific study of the effects drugs have on mood, sensation, thinking, and behavior. It is distinguished from neuropsychopharmacology, which emphasizes the correlation between drug-induced changes in the functioning of cells in the nervous system and changes in consciousness and behavior.
Dopamine is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% of the catecholamine content in the brain. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons to send signals to other nerve cells. Neurotransmitters are synthesized in specific regions of the brain, but affect many regions systemically. The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational component of reward-motivated behavior. The anticipation of most types of rewards increases the level of dopamine in the brain, and many addictive drugs increase dopamine release or block its reuptake into neurons following release. Other brain dopamine pathways are involved in motor control and in controlling the release of various hormones. These pathways and cell groups form a dopamine system which is neuromodulatory.
Operant conditioning is a type of associative learning process through which the strength of a behavior is modified by reinforcement or punishment. It is also a procedure that is used to bring about such learning.
Classical conditioning is a behavioral procedure in which a biologically potent stimulus is paired with a previously neutral stimulus. It also refers to the learning process that results from this pairing, through which the neutral stimulus comes to elicit a response that is usually similar to the one elicited by the potent stimulus.
In internal medicine, relapse or recidivism is a recurrence of a past condition. For example, multiple sclerosis and malaria often exhibit peaks of activity and sometimes very long periods of dormancy, followed by relapse or recrudescence.
Sensitization is a non-associative learning process in which repeated administration of a stimulus results in the progressive amplification of a response. Sensitization often is characterized by an enhancement of response to a whole class of stimuli in addition to the one that is repeated. For example, repetition of a painful stimulus may make one more responsive to a loud noise.
The medial forebrain bundle (MFB), is a neural pathway containing fibers from the basal olfactory regions, the periamygdaloid region and the septal nuclei, as well as fibers from brainstem regions, including the ventral tegmental area and nigrostriatal pathway.
Sex and drugs date back to ancient humans and have been interlocked throughout human history. Both legal and illegal, the consumption of drugs and their effects on the human body encompasses all aspects of sex, including desire, performance, pleasure, conception, gestation, and disease.
The reward system is a group of neural structures responsible for incentive salience, associative learning, and positively-valenced emotions, particularly ones involving pleasure as a core component. Reward is the attractive and motivational property of a stimulus that induces appetitive behavior, also known as approach behavior, and consummatory behavior. A rewarding stimulus has been described as "any stimulus, object, event, activity, or situation that has the potential to make us approach and consume it is by definition a reward". In operant conditioning, rewarding stimuli function as positive reinforcers; however, the converse statement also holds true: positive reinforcers are rewarding.
In psychology, impulsivity is a tendency to act on a whim, displaying behavior characterized by little or no forethought, reflection, or consideration of the consequences. Impulsive actions are typically "poorly conceived, prematurely expressed, unduly risky, or inappropriate to the situation that often result in undesirable consequences," which imperil long-term goals and strategies for success. Impulsivity can be classified as a multifactorial construct. A functional variety of impulsivity has also been suggested, which involves action without much forethought in appropriate situations that can and does result in desirable consequences. "When such actions have positive outcomes, they tend not to be seen as signs of impulsivity, but as indicators of boldness, quickness, spontaneity, courageousness, or unconventionality" Thus, the construct of impulsivity includes at least two independent components: first, acting without an appropriate amount of deliberation, which may or may not be functional; and second, choosing short-term gains over long-term ones.
Positive affectivity (PA) is a human characteristic that describes how much people experience positive affects ; and as a consequence how they interact with others and with their surroundings.
Ro64-6198 is a nociceptoid drug used in scientific research. It acts as a potent and selective agonist for the nociceptin receptor, also known as the ORL-1 receptor, with over 100x selectivity over other opioid receptors. It produces anxiolytic effects in animal studies equivalent to those of benzodiazepine drugs, but has no anticonvulsant effects and does not produce any overt effects on behaviour. However it does impair short-term memory, and counteracts stress-induced anorexia. It also has antitussive effects, and reduces the rewarding and analgesic effects of morphine, although it did not prevent the development of dependence. It has been shown to reduce alcohol self-administration in animals and suppressed relapses in animal models of alcoholism, and ORL-1 agonists may have application in the treatment of alcoholism.
CP-94253 is a drug which acts as a potent and selective serotonin 5-HT1B receptor agonist, with approximately 25x and 40x selectivity over the closely related 5-HT1D and 5-HT1A receptors. It has a range of behavioral effects, based on animal testing. The effects include the following: promoting wakefulness by increasing dopamine release in the brain; reducing food intake and promoting satiety; enhancing the reinforcing effects of cocaine; and possible antidepressant effects.A recent study found that "Regardless of sex, CP94253 decreased cocaine intake after abstinence and during resumption of SA [self-administration] and decreased cue reactivity" suggesting that agonism of the inhibitory 5-HT2B receptors may diminish the cognitive reward of cocaine usage and increased use of the drug without a period of abstinence may be a product of test subjects trying to achieve a previously rewarding experience through larger dosages of cocaine.
Conditioned place preference (CPP) is a form of Pavlovian conditioning used to measure the motivational effects of objects or experiences. By measuring the amount of time an animal spends in an area that has been associated with a stimulus, researchers can infer the animal's liking for the stimulus. This paradigm can also be used to measure conditioned place aversion with an identical procedure involving aversive stimuli instead. Both procedures usually involve mice or rats as subjects. This procedure can be used to measure extinction and reinstatement of the conditioned stimulus. Certain drugs are used in this paradigm to measure their reinforcing properties. Two different methods are used to choose the compartments to be conditioned, and these are biased vs. unbiased. The biased method allows the animal to explore the apparatus, and the compartment they least prefer is the one that the drug is administered in and the one they most prefer is the one where the vehicle is injected. This method allows the animal to choose the compartment they get the drug and vehicle in. In comparison, the unbiased method does not allow the animal to choose what compartment they get the drug and vehicle in and instead the researcher chooses the compartments.
Amphetamine dependence refers to a state of psychological dependence on a drug in the amphetamine class. Stimulants such as amphetamines and cocaine do not cause physical dependence.
Addiction is a neuropsychological disorder characterized by a persistent and intense urge to engage in certain behaviors, often usage of a drug, despite substantial harm and other negative consequences. Repetitive drug use often alters brain function in ways that perpetuate craving, and weakens self-control. This phenomenon – drugs reshaping brain function – has led to an understanding of addiction as a brain disorder with a complex variety of psychosocial as well as neurobiological factors that are implicated in addiction's development. Classic signs of addiction include compulsive engagement in rewarding stimuli, preoccupation with substances or behavior, and continued use despite negative consequences. Habits and patterns associated with addiction are typically characterized by immediate gratification, coupled with delayed deleterious effects.
PNU-99,194(A) (or U-99,194(A)) is a drug which acts as a moderately selective D3 receptor antagonist with ~15-30-fold preference for D3 over the D2 subtype. Though it has substantially greater preference for D3 over D2, the latter receptor does still play some role in its effects, as evidenced by the fact that PNU-99,194 weakly stimulates both prolactin secretion and striatal dopamine synthesis, actions it does not share with the more selective (100-fold) D3 receptor antagonists S-14,297 and GR-103,691.
Addiction is a state characterized by compulsive engagement in rewarding stimuli, despite adverse consequences. The process of developing an addiction occurs through instrumental learning, which is otherwise known as operant conditioning.
A behavioral change can be a temporary or permanent effect that is considered a change in an individual's behavior when compared to previous behavior. It is sometimes considered a mental disorder, yet it is also a strategy used to improve such disorders. This change is generally characterized by changes in thinking, interpretations, emotions, or relationships. These changes can be either good or bad, depending on which behavior is being affected. Often, it takes much more work to change behavior for the better than it does to experience a negative change. Medications can cause this change as a side effect. The interaction between physiological processes and their effect on individual behavior is the basis of psychophysiology. Several theories exist as to why and how behavioral change can be affected, including behaviorism, Self-efficacy theory, and the stages of change model.
David H. Barlow is an American psychologist and Professor Emeritus of Psychology and Psychiatry at Boston University. He is board certified by the American Board of Professional Psychology. Barlow is known for his research and publications on the etiology, nature, and treatment of anxiety disorders. The models and treatment methods that he developed for anxiety and related disorders are widely used in clinical training and practice. Barlow is one of the most frequently cited psychologists in the world.
References
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- ↑ "Jane Stewart CV" (PDF). Concordia University. 2015. Retrieved 2019-12-13.
- ↑ "Jane Stewart". www.concordia.ca. Retrieved 2016-03-09.
- ↑ Eikelboom R, Stewart J (September 1982). "Conditioning of drug-induced physiological responses". Psychological Review . 89 (5): 507–28. doi:10.1037/0033-295X.89.5.507. PMID 7178331.
- ↑ Stewart J (June 1992). "Neurobiology of conditioning to drugs of abuse". Annals of the New York Academy of Sciences . 654 (1): 335–46. Bibcode:1992NYASA.654..335S. doi:10.1111/j.1749-6632.1992.tb25979.x. PMID 1321575. S2CID 29924902.
- ↑ Stewart J, de Wit H, Eikelboom R (April 1984). "Role of unconditioned and conditioned drug effects in the self-administration of opiates and stimulants". Psychological Review. 91 (2): 251–68. doi:10.1037/0033-295X.91.2.251. PMID 6571424.
- ↑ Amir S, Stewart J (February 1996). "Resetting of the circadian clock by a conditioned stimulus". Nature . 379 (6565): 542–5. Bibcode:1996Natur.379..542A. doi:10.1038/379542a0. PMID 8596633. S2CID 4325922.
- ↑ Stewart J, Rajabi H (August 1996). "Initial increases in extracellular dopamine in the ventral tegmental area provide a mechanism for the development of desipramine-induced sensitization within the midbrain dopamine system". Synapse . 23 (4): 258–64. doi:10.1002/(SICI)1098-2396(199608)23:4<258::AID-SYN3>3.0.CO;2-6. PMID 8855510. S2CID 37789995.
- ↑ Samaha AN, Seeman P, Stewart J, Rajabi H, Kapur S (March 2007). ""Breakthrough" dopamine supersensitivity during ongoing antipsychotic treatment leads to treatment failure over time". Journal of Neuroscience . 27 (11): 2979–86. doi:10.1523/JNEUROSCI.5416-06.2007. PMC 6672560 . PMID 17360921.
- ↑ Mitchell JB, Stewart J (March 1990). "Facilitation of sexual behaviors in the male rat associated with intra-VTA injections of opiates". Pharmacology Biochemistry and Behavior . 35 (3): 643–50. doi:10.1016/0091-3057(90)90302-X. PMID 1971113. S2CID 45442957.
- ↑ Mitchell JB, Stewart J (February 1990). "Facilitation of sexual behaviors in the male rat in the presence of stimuli previously paired with systemic injections of morphine". Pharmacology Biochemistry and Behavior. 35 (2): 367–72. doi:10.1016/0091-3057(90)90171-D. PMID 2320644. S2CID 6336713.
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