Drug consumption among the student population of Mexico City and its metropolitan area: subgroups affected and the distribution of users

Sections

ABSTRACT
Method
Findings and discussion
Conclusions
Acknowledgements

Details

Author: María Elena CASTRO, Marcelo VALENCIA
Pages: 29 to 37
Creation Date: 1980/01/01

Drug consumption among the student population of Mexico City and its metropolitan area: subgroups affected and the distribution of users

María Elena CASTRO
Mexican Institute of Psychiatry, Mexico City, Mexico Marcelo VALENCIA
Mexican Institute of Psychiatry, Mexico City, Mexico

ABSTRACT

The results of a survey based on a sample of 4,059 students attending intermediate and upper intermediate schools in Mexico City and its metropolitan area showed that the percentage of drug use "ever" by substance was the following: alcohol, 59; tobacco, 53.2; inhalants, 5.4; cannabis, 3.8; tranquillizers, 3.1; amphetamines, 2.7; sedatives, 1.3; opium, 0.91; LSD, 0.54; cocaine, 0.52; heroin, 0.29. Of the students reporting use "ever", the percentage reporting use of one of these substances "in the past month" ranged from 22.5 to 58.3. While there were more female students among the users of tranquillizers and stimulants, male students predominated among the users of other substances, with the difference being most pronounced among cannabis users. Older students were more involved with cannabis; in contrast, inhalants were more popular with younger students. The use of other substances varied little with age. Use of alcohol and cannabis was also most frequent among students of schools in middle, upper middle and upper class areas, whereas use of inhalants was most common among students attending schools in lower class areas.

This paper is a follow-up to previous work measuring the use of drugs in the Mexican student population. The collection of data was first begun in Mexico in 1975 to ascertain the patterns of drug use in this population group. The results of studies carried out to date have been reported by Chao and Castro (1976); Castro et al. (1978); Castro and Valencia (1978); Medina-Mora and Campillo (1978); and Campillo et al. (1979).

Information is presented on drug use observed in a representative sample of students attending intermediate and upper intermediate schools (97 per cent of whom were between the ages of 14 and 18) in Mexico City and its metropolitan area.

The findings include the following:

  1. Characteristics of use (prevalence), i.e. the percentages of use of each of the drugs investigated in terms of use at some time in the respondent's lifetime and use in the past month;

  2. Subgroups affected by the use of drugs, i.e. the subgroups in which there are relatively large numbers of users in terms of age, sex, number of completed school years and type of school;

  3. Distribution of users, i.e. the substances abused and the proportion of light, moderate and heavy users.

Method

The study sample consisted of students attending intermediate and upper intermediate schools during the school year 1978/79.

To obtain the sample, information provided by the Secretariat of Public Education was used and the following types of school were distinguished: secondary, preparatory, pre-vocational, vocational, technical and business. A socio-economic map 1of Mexico City and its metropolitan area was also used to place schools by socio-economic conditions of an area (upper, upper middle, middle and lower class) or location outside Mexico City.

Socio-economic areas were defined according to the following variables: living conditions, types of public services available in the area, incomes of heads of family and the ratio of the number of automobiles to the number of family members. The schools classified as located outside Mexico City were those in suburban areas on the geographical boundaries of the city, which constitute the "metropolitan area".

The sample was chosen in two stages. First, schools were selected according to type and socio-economic area. Then, groups of students within the schools were chosen by simple random sampling. The total sample consisted of 4,059 students out of an estimated population of 600,000 students. The distribution of the sample is indicated in table 1.

A self-administered questionnaire was used, prepared in co-operation with the World Health Organization and first checked for validity in a pilot study carried out in Mexico by the Mexican Drug Dependence Centre (CEMEF), later called the Mexican Centre of Mental Health Studies (CEMESAM). This questionnaire investigated the use of the following drugs: alcohol, tobacco, cannabis, amphetamines, cocaine, hallucinogens, inhalants, tranquillizers (such as diazepoxide, diazepam and meprobamate), sedatives (barbiturates and non-barbiturate sedative hypnotics), opium, heroin and other opiates.

Two categories of use were distinguished: use "ever" and use "in the past month". The second category was further broken down to indicate frequencies of 1 to 5 times, 6 to 19 times and 20 times or more. The level of drug use was scored for each respondent and for each drug. Possible scores ranged from 0 to 48.

Table 1

Demographic description of the sample (N = 4,059)

Characteristic

Number

Fraction of total (%)

Sex
   
Male
2009 49.5
Female
2013 49.6
Not stated
37 0.9
Age
   
<14
41 1.0
14 1172 28.9
15 1267 31.2
16 714 17.6
17 447 11.0
18 235 5.8
>18
91 2.2
Not stated
92 2.3
Number of completed school years
   
7 104 2.6
8 1103 27.2
9 1667 41.1
10 459 11.3
11 257 6.3
12 259 6.4
13 45 1.1
14 19 0.5
Not stated
146 3.6

Three types of users were then distinguished:

Light drug users: score 1-3

Moderate drug users: score 4-6

Heavy drug users: score 7 or greater.

Methodological map of the metropolitan area of Mexico City, Buró de Investigaciones de Mercados, S.A. (BIMSA).

Findings and discussion

Characteristics of use (prevalence)

The drugs most widely used, whether "ever" or "in the past month", in descending order, were alcohol, tobacco, inhalants, cannabis, tranquillizers, amphetamines and sedatives. The percentages of use of opium, LSD, cocaine and heroin were smaller. It was found that users of tobacco, heroin and cocaine experienced greater difficulty in limiting their use to the "ever" level, in comparison with the remainder of the drugs investigated, since approximately half of those who reported ever having used one of these drugs also reported having used it "in the past month" (table 2).

Table 2

Characteristics of use by substance

 

Use "ever"

Use "in the past month"

Substance

Number of users

Percentage of total sample

Number of users

Percentage of all users of the substance

Alcohol
2397 59.0 665 27.7
Tobacco
2159 53.2 1094 50.7
Inhalants
221 5.4 62 28.0
Cannabis
156 3.8 46 29.5
Tranquillizers
126 3.1 34 27.0
Amphetamines
111 2.7 25 22.5
Sedatives
52 1.3 19 36.5
Opium
37 0.91 13 35.1
LSD
22 0.54 7 31.8
Cocaine
21 0.52 10 47.6
Heroin
12 0.29 7 58.3

Subgroups affected by the use of drugs

The subgroups most affected by the use of alcohol, tobacco and cannabis were male students, those in the preparatory grades (14 completed school years) and those aged 18 or more. As regards the type of school, the subgroups most affected by the use of alcohol and cannabis were students of schools in the middle class, upper middle class or upper class areas. The subgroups most affected by the use of inhalants were male students, those in the under 14, 14 and 15 years age groups, those who reported having completed 8, 10 or 14 years in the school, those who stated that they had worked during the year prior to the survey, and those who indicated that they attended schools in lower class areas. As regards the use of tranquillizers, the subgroups most affected were female students, those who reported having studied and worked during the previous year and those who indicated that they attended schools in upper or middle class areas (tables 3 and 4).

Table 3

Use of drugs "ever" by demographic variables (Percentages of the totals in the right-hand column)

Variable

Tobacco

Alcohol

Inhalants

Cannabis

Tranquillizers

Amphetamines

Sedatives

Total subjects in subgroup a

Sex
               
Male
59.4 62.7 7.3 6.1 2.6 2.4 1.4 2009
Female
46.8 55.4 3.5 1.5 3.5 3.0 1.1 2013
Age
               
<14
61.1 56.1 9.8 0 4.9 4.9 0 41
14 45.1 53.8 6.1 1.2 3.1 2.5 0.6 1172
15 51.5 58.1 6.2 2.9 2.8 2.5 1.4 1267
16 56.6 56.7 3.6 3.5 3.4 2.5 1.4 714
17 61.7 63.8 4.7 6.3 2.9 3.1 1.6 447
18 66.5 81.7 3.4 13.2 3.8 3.4 2.6 235
>18
69.2 80.2 3.2 14.2 4.3 4.3 2.1 91
Years of school completed
               
7 51.9 55.8 2.9 1.9 0 1.9 0 104
8 49.9 52.7 6.1 2.4 2.9 2.4 0.8 1103
9 49.7 51.1 5.8 2.7 2.7 2.5 1.2 1667
10 61.4 69.9 6.3 5.7 4.4 4.4 2.2 459
11 64.2 66.5 2.3 4.7 6.2 3.1 0.8 257
12 59.5 69.1 1.9 10.4 1.9 2.7 1.9 259
13 60.0 75.6 0 11.1 0 0 2.2 45
14 89.5 94.7 10.5 21.1 0 0 0 19
Study status
               
Not studying
59.0 60.8 8.0 8.0 2.4 2.4 2.4 212
Studying full time
50.4 57.5 4.9 3.1 3.0 2.6 0.9 2363
Studying part time
57.0 61.1 4.5 4.2 3.4 3.2 1.6 1423
Work status
               
Not working
52.9 59.2 5.0 3.3 2.8 2.6 1.1 2906
Working full time
49.2 50.3 6.3 4.2 3.2 0.5 1.6 189
Working part time
58.3 60.6 6.6 6.3 4.3 4.1 2.0 559

aThe number of students for which no information was available is as follows: sex, 37; age, 92; years of school completed, 146; study status, 61; work status. 405.

Table 4

Use of drugs "ever" by location of school (Percentages of the totals in the right-hand column)

Location

Alcohol

Tobacco

Inhalants

Cannabis

Tranquillizers

Amphetamines

Sedatives

Total subjects in subgroup a

Lower class areas
56.0 53.0 6.5 3.9 3.6 3.3 1.6 1935
Middle class areas
56.5 47.6 3.1 4.6 2.0 1.0 0.4 736
Upper middle class area
76.2 57.0 4.5 1.0 6.5 2.7 0.7 400
Upper class area
69.3 57.1 5.2 1.0 4.7 2.1 0.5 189
Outside the city
57.6 57.7 5.3 4.3 3.5 3.0 763  

a Information lacking for 36 students.

Distribution of users

The distribution of users of drugs excluding alcohol and tobacco is continuous and unimodal (figure I), with larger proportions of light users (10.9 per cent), smaller proportions of moderate users (1.6 per cent) and even smaller proportions of heavy users (0.5 per cent) (table 5).

The distribution of users of drugs including alcohol and tobacco is also continuous and unimodal (figure II), with 48 per cent light users, 17.2 per cent moderate users and 5.6 per cent heavy users (table 5).

Table 5

Distribution of users (N = 4,059)

 

Users of drugs, excluding alcohol and tobacco

Users of drugs, including alcohol and tobacco

Score

Number

Fraction of N (%)

Number

Fraction of N (%)

0 5 333 87.0 1 187 29.2
1-3
441 10.9 1 947 48.0
4-6
66 1.6 698 17.2
>7
19 0.5 227 5.6

Figure I

Distribution of users of drugs, excluding alcohol and tobacco

Figure II

Distribution of users of drugs, including alcohol and tobacco

Full size image: 19 kB, Figure I

In comparison with the nation-wide study carried out in Mexico in 1976 (Castro and Valencia, 1978), it was found that use of the same groups of drugs predominated among the student population, but the order of preference is different, since in this study the percentage for use of inhalants was larger than that using cannabis, whereas in the nation-wide study the reverse was the case. It is also observed that use at some time in the respondent's life has substantially increased since 1976 in respect of all drugs except tranquillizers, for which the percentage has remained unchanged. However, use "in the past month" has not undergone any significant change.

The distribution of users found in the nation-wide study in 1976 (Castro, Chao and Smart, 1978) is the same as that described in this study: continuous, unimodal distribution with more light users and fewer heavy users.

Conclusions

In conclusion, it is clear that the number of Mexican students having used drugs is gradually changing as regards use "ever", but that this change is not yet reflected in use "in the past month". In general terms, the demographic subgroups (by age, sex and number of completed school years) most affected by drug use were the same in 1978 as in 1976 and the type of distribution reported has remained unchanged, both in the studies carried out among students by the Centre, and in those carried out inter alia by Smart (1978) and McDermott and Scheurich (1977). That suggests important implications for prevention; if the distribution of users is unimodal and continuous, with the majority being light users, preventing use may result in preventing abuse.

Another important conclusion is that the subgroups most affected vary according to the drug in question. Thus, for example, the subgroups most affected as regards inhalants and sedatives are students indicating that they attend schools located in lower class and marginal areas, and those most affected as regards substances such as alcohol and cannabis are students indicating that they attend schools located in middle and upper class areas.

Acknowledgements

We are particularly grateful for the co-operation of the Secretariat of Public Education through the Directorate-General for Pupil Health and the Directorate of Secondary Schools, who enabled us to administer the questionnaire to pupils in schools under their authority.

Bibliography

001

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002

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003

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004

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005

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006

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