Cigarette smoking involves the inhalation of smoke derived from the burning of tobacco. In addition to nicotine, cigarette smoke contains several thousand other chemicals, many of which are very dangerous, to ease the cravings of a regular smoker. While nicotine itself is known to be the addictive substance, the play among the different compounds within cigarette smoke may contribute to the overall need to use cigarettes. Many of these pathways are not clearly understood but certain chemicals have now been identified that have a similar effect on the central nervous system. Cigarette smoking is an addiction, both in the physiological and psychological sense.
A physiological addiction means that the substance(s) has a measurable effect on the body and this effect is desired to maintain the altered level of functioning within the body. In terms of a physiological addiction, nicotine and several other substances known as monoamine oxidase inhibitors found in cigarette smoke act on specific receptors in the central nervous system. The effect is to increase the levels of several neurotransmitters in the CNS and reduce the enzymatic activity which reduces the levels of these neurotransmitters. Ultimately the levels of these neurotransmitters induce a sense of euphoria and stimulate the reward center in the brain.
Failure to receive an adequate dose of nicotine and the other substances involved in cigarette addiction allows the neurotransmitter levels to drop. A person may experience a host of withdrawal symptoms, most notably irritability, difficulty concentrating, anxiety and depression. This also supports the psychological dependence on nicotine. Nicotine has a half life of about 2 hours, therefore a person has to consume substances containing nicotine several times in a day to maintain the desired effect.
Apart from its action on the central nervous system, nicotine also acts on other sites in the body, usually as a result of action on the nerves supplying it. This includes the blood vessels, heart and bowels among other organs and systems. In terms of the cardiovascular system, nicotine increases the heart rate and causes blood vessels to constrict (narrow) thereby increasing blood pressure. With the bowels, the action of nicotine may increase bowel activity and therefore many smokers report constipation or less frequent bowel movements once quitting cigarettes.
Psychological dependance can be a bit difficult to understand and is probably best assessed in comparison to physiological addition. Whereas physiological or physical addiction is characterized by a craving for a substance evident by the presence of withdrawal symptoms, psychological addiction is more a feeling of “need” for the substance. This may be based on a host of factors that extends beyond the person’s mental status. A part of it is also a social “need” where one is among smokers, and feels that smoking is necessary for social integration and acceptance.
Psychological dependence infers that nicotine is needed to remove or reduce certain mental disturbances like anxiety and depression. Without this effect, the mental impairment is significant enough to affect daily functioning. In fact, many cigarette smokers may have underlying depression and are only able to quit with the help of antidepressant drugs. Counseling and support groups are therefore advisable for recovering ex-smokers even after the withdrawal symptoms have resolved.