When people begin using marijuana as teenagers, the drug may impair thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions. Researchers are still studying how long marijuana's effects last and whether some changes may be permanent. For example, a study from New Zealand conducted in part by researchers at Duke University showed that people who started smoking marijuana heavily in their teens and had an ongoing marijuana use disorder lost an average of 8 IQ points between ages 13 and The lost mental abilities didn't fully return in those who quit marijuana as adults.
Lifetime, Annual, and Day Prevalence, The pattern of cocaine use is more complicated. Public concern, in contrast, increased dramatically from toat just about the same time that survey measures of student consumption were beginning to decline. College students are surveyed annually in conjunction with the surveys of high school seniors.
The decline in illicit drugs evident among high school students also occurred among college students: Current marijuana use was 16 percent in compared with 34 percent inand current cocaine use was down to 2. Similar declines were reflected in the household surveys. Consumption of illicit drugs is most prevalent among young adults ages and older.
Current marijuana use for this group was 35 percent inand less than half that in 16 percent. Similarly, current cocaine use dropped by half, from 9.
It is clear from survey data that the overall profile of household and student population involvement with illicit drugs is down—and down dramatically see Figure 1.
How these trends translate into higher levels of consumption is less certain. The National Household Survey reported that, among those who used cocaine at all in the last year, 10 percent used the drug once a week or more, and 4 percent used it daily or almost daily; among the past-year users, 5 percent were weekly users and 2 percent daily or almost daily users.
The surveys of high school seniors showed contrasting findings: Thus, even among the general populations covered by these two surveys, there is some question about the degree to which drug involvement at the level of abuse and dependence may be declining, despite the overall drop in rates of use.
Moreover, there are some very significant gaps in the population covered by the two surveys, and the poorly represented populations may be behaving differently from those who are well represented.
The high school senior surveys, for example, do not include high school dropouts, and there is ample evidence that drug problems are likely to be more severe among segments of the population in which dropout rates are likely to be greatest, such as economically disadvantaged populations in inner cities.
The household surveys also exclude all individuals not living in conventional households, such as those in group quarters, institutions, or transient places. Both surveys rely on individuals voluntarily agreeing to participate in the study; people who are having severe drug problems are undoubtedly less likely to be available and agreeable to participate in a lengthy interview than are unimpaired household members.
Validity and Reliability of Survey Data Any data collection system that relies on self-reports must address the issue of validity—do people tell the truth or know the truth when they are asked to tell a stranger about their own or another's use of illegal drugs?
A variety of studies have been undertaken to establish the validity of such surveys Rouse et al. Perhaps the most general conclusion that can be supported is that most people are willing to be reasonably truthful within the bounds of their capability under the proper conditions.
Evidence from other areas of survey research suggests that, when respondents believe they are guaranteed anonymity and confidentiality, when they accept the scientific or practical value of the survey, when they accept the legitimacy of the survey, then they tend to be generally truthful Forman and Linney, ; Rouse et al.
Whether these conditions are met in the household drug use survey, the school-based surveys of students, or the mail-out questionnaire follow-up surveys of high school graduates is debatable. The survey operators have worked to develop methods of shielding answers and reassuring respondents, and the federal government has enacted legislation to protect the confidentiality of individual data.
The degree to which confidentiality assurances are believed may vary with social or cultural affiliations and personality characteristics of the respondents. Some of these differences are correlates and predictors of risk for drug use Moncher et al.
Some youth at high risk for drug use may not divulge any illicit drug use if they suspect the interviewer knows who they are for fear of apprehension by legal authorities or punishment by some other social system such as social welfare or education.
But even if the precision and validity of the survey are somewhat compromised by biases, other tests suggest the reliability of trend data over time.
One such factor is the presumption of constancy of bias; even if individual prevalence estimates are systematically biased downward by underreporting, so long as the bias is relatively constant from year to year, trend estimates may be quite reliable.
This presumption is supported by the fact that other responses to drug consumption questions have not drifted away from the self-report trend, as might occur if individuals were becoming increasingly reluctant to self-report.
For example, the high school seniors survey asks respondents what proportion of their friends use a given drug.
Even if there were a change in willingness to report self-behaviors, there should be somewhat less change in willingness to report unnamed friends' behaviors.
However, seniors' reports of their friends' drug practices parallel very closely the trend in reports of their own use.
A second methodological support for validity is that different drugs display different trends over time; self-reported marijuana use declined earlier than did cocaine, and reported use of other drugs including alcohol has not declined.
A third type of evidence bearing on trend validity is that different self-report methods produce similar trend results. Self-administered mail-out questionnaires, group-administered school-based questionnaires, and household interviews using self-completed, sealed answer sheets all provide similar trends.Marijuana: The Facts Marijuana is the most commonly used illegal illegal drug in the United States today.
Therefore, people who have used less accessible drugs such as heroin, cocaine and LSD, are likely to have also used Some effects of marijuana use can include feelings of panic, anxiety and paranoia. Such experiences can be. The United Nations Office on Drugs and Crime's World Drug Report estimates the size of the global illicit drug market at US$ billion in alone.
With a world GDP of US$36 trillion in the same year, the illegal drug trade may be estimated as nearly 1% of total global trade. Short-Term Effects of Marijuana; Side Effects; Long-Term Effects of Marijuana; Marijuana Addiction; Marijuana Withdrawal Treatment; Is Marijuana Harmful?
Marijuana is the most commonly abused illicit drug in the United States.
It is normally smoked as a joint or in a pipe and can also be smoked as a blunt. United States Drug Enforcement Administration regardbouddhiste.com is an official site of the U.S. Department of Justice. Contact Us. Marijuana is reported as the most widely used illicit drug in the US, according to the National Survey on Drug Use and Health.
In the past survey year (), million people, or % of US adults reported using marijuana. United States Drug Enforcement Administration regardbouddhiste.com is an official site of the U.S. Department of Justice. Contact the Webmaster.