Addiction is defined as being an "excessive" obsession, compulsion or dependence on a behavior or substance. If the item or behavior is removed, the person suffers negative psychological and/or physical side effects.
Addictions included, but are not limited to, sex, exercise, spiritual obsession, cutting oneself, shopping, sleeping, people pleasing, perfectionism, pornography, sadism, overachieving, overeating, overworking (workaholic), drugs and other medication, smoking, video games, criminal activity, alcohol, gambling, time on a computer, and tobacco. I am sure text messaging will join this list shortly!
Drugs that can cause addiction/dependence include opiates, amphetamines, benzodiazepines, barbiturates, alcohol and nicotine.
These addictive behaviors can cause feelings of guilt, shame, fear, failure, anxiety, humiliation and depression. It's not unusual for an addicted person to experience rejection from others and even homelessness.
Some of the above listed activities are psychological addictions, some are physical addictions and some are both. When an addicted person quits the behavior, he or she will go through "withdrawal" which is a negative physical and/or psychological experience. This bad experience causes the person to strongly want to return to the behavior to make the withdrawal symptoms stop.
Psychological withdrawal experiences include cravings, irritability, insomnia, depression and loss of appetite. Physical withdrawal symptoms include delirium, hallucinations, panic attacks, diarrhea, headaches, nausea, heart palpitations and irregular beats, seizures, weakness, sweating, tremors and death.
There are several theories as to the exact cause of addiction. They focus on either biology, genetics, society or psychology. No one knows for sure. That's why these are called "theories."
The Disease Model of Addiction holds that addiction is the result of either the impairment of neuro-chemical or behavioral processes, or of some combination of the two. The American Medical Association, National Association of Social Workers, and American Psychological Association all have policies which are based on this theory.
The Pleasure Model says that addiction is a strong fixation on pleasureful stimulation that becomes so strong that it captivates an individual with the strength of natural drives. This model is used as one of the reason for zero tolerance for use of illicit drugs
The Genetic Model theorizes a genetic predisposition to certain behaviors. It is frequently documented that certain addictions "run in the family." Genetics are thought to be a co-contributor to the cause of addiction.
The Experiential Model says that addictions occur with regard to experiences involving the behavior or substance. It says that addiction is temporary and is often outgrown naturally.
The Opponent-Process Model states that addiction can occur whenever a negative psychological event that is followed by a positive psychological event. There are many examples of opponent processes in the nervous system including taste, motor movement, touch, vision, and hearing. Opponent-processes occurring at the sensory level may translate "down-stream" into addictive or habit-forming behavior.
The Allostatic Model says continued use of a drug leads needing higher and higher doses over time to maintain the same level of feeling. It becomes an out of control spiralling of increased use, negative emotional states and increasing withdrawal.
The Cultural Model theorizes that the influence of culture determines whether or not individuals becomes addicted. This model states that people do not become addicted to things that are not part of or are not available within their own cultures. On the other hand, when a person is exposed to possible addictive substances and doesn't learn moderation through their developmental years, they can be very likely to abuse these substances.
The Moral Model states that addictions are the result of human weakness and are defects of character and reject the notion that there is any biological basis for addiction. They often have little sympathy for people with serious addictions. The moral model is commonly applied to dependency on illegal substances even though it is considered to have no therapeutic value in treatment.
The Habit Model rejects the concept of "addiction" and says the behavior is merely a habit that is socially unacceptable, resulting in persecution. This model further states that the concept of mental illness is a myth.
Finally, the Blended Model attempts to bring together all the other models in developing a therapeutic approach to dependency. It says that dependency is unique set of circumstances for each individual and that each case must be treated individually.