DRUG ADDICTION

Individual addictions are chronically relapsing disorders characterized by compulsive drug use, an inability to restrict the consumption of drugs and the development of a withdrawal syndrome through cessation of medication use.

HOW IT AFFECTS BRAIN FUNCTION AND STRUCTURE

Areas of the mind are disrupted by drug misuse, as the National Institute on Drug Abuse (NIDA) reports that the brain stem, limbic system, and cerebral cortex are influenced. The brain stem controls life-sustaining works, such as sleeping, breathing, and heart rate, whereas the circulatory system retains the mind's reward circuitry and helps to control feelings and the capacity to feel joy. The cerebral cortex is known as the "believing centre" of the mind, handling problem-solving, preparation, and decision-making skills in addition to helping individuals to process information offered by their own perceptions.

The more frequently medications are used, the longer they'll affect brain chemicals and circuitry, which may result in drug addiction and withdrawal symptoms once the drugs procedure from their human body. Drug cravings, addiction, and withdrawal symptoms, combined with a loss of control over usage, are signs of dependence

DEPENDENCE

Dependence was defined as a bunch of behavioral, physiological and cognitive phenomena that develop after repeated chemical use. It typically comprises a powerful urge to take the medication, problems in controlling its own use, persisting in its use despite harmful effects, a higher priority given to drug use than to other tasks and responsibilities, higher endurance and occasionally a physical withdrawal condition.

CHEMICAL SUBSTANCES CAUSE ADDICTION

• Opiates (morphine, heroin)
• Cocaine
• Amphetamine and like drugs
• MDMA (ecstasy)
• PCP (phencyclidine or angel dust)
• Marijuana
• Tobacco (nicotine)
• Alcohol (ethanol)
• Sedative

MECHANISM

Drug Dependence has been conceptualized as a Complicated and Chronic disease process happening in the mind, which can be modulated by genetic, environmental and developmental aspects. The most consistent and reproducible finding in drug dependence is that abused chemicals trigger the mesolimbic dopamine system, which strengthens both natural and pharmacological benefits.

Opioids, These compounds have specific receptors within the mind and also the rise in dopamine levels in the mesolimbic system would be your last effect they create. Receptor-mediated action is the main mechanism where any substance messenger functions. Receptors have two key purposes of recognition and transduction. Correspondingly, every receptor has two domain names, i.e., a ligand-binding and an effector domain name. The ligand-binding domain name has a hydrophilic and a lipophilic area and is ordinarily heteropolymeric. The binding of this ligand induces a change in the quaternary structure of this receptor.

Receptors Have different effector mechanisms, which can be widely of four different types:

1. G protein-coupled receptors
2. Receptors with intrinsic ion channels
3. Enzymatic receptors
4. Receptors regulating gene expression

ROLE OF DOPAMINE

• VTA

-- Gains trigger the neurons.

• Drugs directly and strongly trigger these participants without a link to purposeful behaviour.

• This also contributes to a deep corruption of this Brain's reward mechanisms: medication slowly, progressively, and insidiously replace natural reward as the significant shaper of behaviour

Medicines can upregulate or downregulate their receptors and their effector mechanisms . These modifications are effected through hereditary mechanics and are also implicated in the development of tolerance and withdrawal. Earlier biochemical data affirmed the site of action of medication has been homogeneous. It's known that there is fantastic diversity in drug-receptor interactions.
** For instance**,nicotine was believed to possess a homogeneous class of binding sites within the mind. It's proven that there are lots of different oligomeric receptors which bind and are activated by smoking.

CONCLUSION

The final common pathway of this activity of drugs of abuse is by way of dopamine from the limbic system. Chronic administration of medication contributes to molecular fluctuations in more than 1 neurotransmitter system and therefore, various neurotransmitter systems are included with the growth of dependence on a single medication. Assessing the neurobiological basis of addictive procedures allows better comprehension of current pharmacotherapy and can lead to the evolution of new and more efficacious therapy strategies later on.