Addiction – The body`s adaptation to the repeated use of certain products;discontinuing their use is characterized by abstinence.Abstinence effects can be physical or mental.
Toleration – Lower response to the same amount of drug use,making you increase the dose.
Sensitiveness – More powerful and irreversible reaction to repeated use of the same quantity of psychoactive substances.
Withdrawal – Is an abstinence syndrome, manifested by a strong physical and mental suffering caused by stopping the drug use
Action on the brain
Through the lung and oral mucosa, nicotine is spreading throughout the body.In the brain, it mimics the action of a neurotransmitter,acetylcholine, and is fixed on nicotinic receptors, located on the surface of many neurons.It has a stimulating effect on central nervous system, especially the reward system.Amplify the secretion of dopamine by activating neurons that produce it. Harmani Alkaloids maintain a high concentration of dopamine,serotonin and norepinephrine in the synapses, reducing the activity of enzymes that degrade them.Increase attention and concentration. Becomes easier to bear states such as anxiety or hunger. Smoking can cause nausea, dizziness andheadaches.
Tolerance and addiction
Regular use of tobacco maintains in brain a high concentration of nicotine.His receptors are becoming less sensitive and not sufficiently stimulate the secretion of dopamine.The smoker does not feel the pleasure of his first cigarettes.After a period of abstinence for several hours (at night), level of nicotine decreases,and nicotinic receptorsbecome hypersensitive.As a result,the action of acetylcholine exceeds the normal level and begins a state of turmoil and weakness.The next dose will excessively stimulate the receptors,triggering a massive discharge of dopamine.After this first intoxication, tolerance is installed. Smoker entersthe vicious circle of smoking.The pleasure felt diminishes, and tofind balance, the addict needs to use the drug again.
Nicotine and Harmani alkaloids are the key molecules in tobacco addiction but there are other compounds(tar and carbon monoxide) responsible for general toxicity.They cause cardiovascular disease(damage to arteries,vasoconstriction, hypertension, arrhythmia, blood clotting in thevessels, risk of myocardial infarction), respiratory disease(reduced oxygen to the brain and muscle, decrease dresistance to effort, chronic bronchitis), ulcers and cancer (the gastrointestinal tract, the respiratory system).The smoker may suffer from sleep disorders and anxiety. Food‘s behavior is modified by the loss of taste, smell and appetite.
Symptoms of abstinence: for two or three days, sleeping problems, anxiety and memory difficulties.Under observation: withdrawal is possible without an effort, but it is often necessary to resort to treatments.By this stage, scientists believe nicotine substitutes (patches, chewing gum) as the most effective.
So,as this article says,you should think twice before start smoking or drinking.