In recent years, the quality of life has been considered an important index in medical research for evaluating the individual health status and for decision making and judgment about the general health of the society, as well as finding the main problems in different dimensions of life (
1). Quality of life possesses different dimensions such as physical health, mental health, economic conditions, personal beliefs, and interaction with the environment (
1,
2). Also, it is regarded very important, as it includes several dimensions of the individual such as physiological aspects, performance, and the existence (
3). The quality of life is so important that the current century is called the century of improving life quality (not only surviving) and health status (
4,
5). Life quality confines not only to the health status aspects, but also many other factors; however, health status is the core and the prerequisite of a good quality of life (
6,
7). Some scholars believe that life quality is the individual’s evaluation of his or her health status and satisfaction gained from this understanding (
8). The World Health Organization has defined quality of life as the understanding that people have of their life situation in their cultural context and value systems which is related to their goals, expectation, and criteria in their lives (
9). Therefore, quality of life can be defined as the physical, mental, and social welfare (such as happiness, satisfaction, pride, health, economic status, educational opportunities, and so on) which is understood by an individual or group (
7,
9). Health-related quality of life (HRQOL) is a patient’s perception of how his or her health status affects physical, psychological and social functioning, and well-being (
10).
Addiction, substance dependence and its illicit trade are nowadays one of the major concerns and health threatening factors in the world (
11,
12). Risk factors of narcotic drug abuse include family conflicts, education problems, and simultaneous occurrence of mental disorders such as depression and mood changes, drug abuse by parents and peers, and early onset of cigarette smoking. The more risk factors a person has, the higher would be the probability of drug abuse for that person (
13). In patients, life quality refers to a good situation which reflects the physical, mental and social status of the person. Negative consequences of the mental status (depression, anxiety, and collapse of family relationship), and physical status (bodily pain and inertia) of addiction are associated with drug abuse. These consequences result in the reduction of life quality and satisfaction in substance dependent people (
14-
16).
According to WHO report in 2008, 200 million people in the world were opioid dependent and Iran is also exposed to this social problem because of its geographical position (
17,
18). Drug dependence is more common among men and even some studies report that the prevalence of addiction among men is 15 times more than that among women in Iran. The highest frequency of addiction is also in 20 - 35 years age group (
17).
In recent years, a lot of attention has been paid to the health status and life quality, especially of the addicts (
19,
20). The results of various studies indicate that the quality of life of addicts is lower than that of normal people (
12,
14-
16,
21,
22). Some studies have also shown that methadone and buprenorphine maintenance treatments have had positive effects on the life quality of the addicts (
23-
27).