Physical Addiction

Disease of Addiction


5- Physical Addiction


While the previous page dealt with the changes that occur in our mind as people addicted to substances, this page explains the symptoms of physical addiction. The information serves to help in understanding why we lose the power to stop our addiction on our own.


  • Brain’s reward circuit is over stimulated
  • Brain’s natural chemical messengers are disrupted


There are two changes that happen in the brain’s function and structure as a result of prolonged drug abuse. They are:

Physical addiction changes the brain's structure


1- Brain’s reward circuit is over stimulated

Prolonged abuse of drugs changes the function and structure of the brain. When this occurs, the disease of addiction can be said to have developed, because the brain is now dependent on drugs to function normally. Dopamine, a naturally occurring chemical in the brain, produces a sense of pleasure and reward. Vigorous exercise, for instance, boosts dopamine levels and results in a feeling of well being. Drugs, though, cause unnaturally large amounts of this chemical to be manufactured by the body, which is why the person feels euphoric and “high”. But because the brain is being given external chemicals (drugs) to feel pleasure or reward, it slowly loses the ability to produce its own natural feel-good chemicals – dopamine.

The brain’s reward circuit is impacted in two ways through drug abuse:


1st impact: After repeated drug-induced “highs,” the brain loses its ability to gain pleasure from normal activities. For example, normal people may enjoy going to the movies, but addicts — having experienced intense states of euphoria — lose the ability to enjoy the simple pleasures of life.

2nd impact: as the brain constantly adapts to increasing external chemicals, it requires more and more drugs to function normally.


2- Brain’s natural chemical messengers are disrupted

The second physical effect of drug abuse on the brain is the disruption of its communication system, which can be seen in two symptoms:


1st symptom: Cravings

  • A craving occurs when the brain is physically activated to produce a powerful urge or impulse to use drugs. Cravings are like strong memories that are linked to the effect of drugs on the brain’s neurochemistry. For example, if we see others using drugs, our brain gets physically activated or carves to use drugs. If we then don’t supply our body with the drug, it reacts through physical withdrawal symptoms.
  • Withdrawal is the body’s way of broadcasting that it is dependent on drugs. It is as if our body inflicts punishment on us to supply it with drugs. Withdrawals can be both physical and psychological.
  • Psychological withdrawal symptoms include: anxiety, irritability, restlessness, insomnia, headaches, difficulty concentrating, and depression.
  • Physical withdrawal symptoms include: heavy sweating, palpitations, diarrhoea, laboured breathing, shaking, nausea, vomiting, muscle aches and chest tightness.
  • Facing withdrawals is a frightening prospect for us and can be a deterrent to seeking treatment.
  • Bear in mind: Withdrawal symptoms vary — and can be dangerous, leading to seizures, strokes or heart attacks. It is important to seek medical help when dealing with withdrawals.


2nd symptom: Tolerance

  • Another feature of the disease of addiction is the development of tolerance, which results in gradually needing more and more of a drug to experience the same effect. This can lead us to reach the point where our regular dose of drugs would put the life of a non-addict in danger.
  • In the language of 12 Steps, tolerance is commonly referred to as our Allergy toward drugs, setting off a craving that would not occur in the non-addict. Our allergy toward drugs is shown in our compulsion to use a drug more and more despite its harmful consequences. This is considered an allergy because our reaction is abnormal – instead of stopping we continue using drugs. The phenomenon of an allergy to a substance is demonstrated on a big scale with alcohol. For example, many non-alcoholics in the world are able to sip a glass of whiskey for what seems like ages – and then stop. With the alcoholic, though, the first drink very often sets off the allergy, leading to a binge. The alcoholic, like the addict, has lost control over the substance. The drink or the drug is in charge, leaving us powerless in the face of our disease.

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