Content uploaded by Yeshigeta Birhanu
Author content
All content in this area was uploaded by Yeshigeta Birhanu
Content may be subject to copyright.
Effect of Substance Use on Academic Achievement of Health Officer Kalayu M. et al
155
ORIGINAL ARTICLE
EFFECT OF SUBSTANCE USE ON ACADEMIC ACHIEVEMENT
OF HEALTH OFFICER AND MEDICAL STUDENTS OF JIMMA
UNIVERSITY, SOUTHWEST ETHIOPIA
Kalayu Meressa
1
, MD, Andualem Mossie
2
, PhD, Yeshigeta Gelaw
3
, MD
ABSTRACT
BACKGROUND: Khat (Catha edulis Forsk) chewing habit is becoming a national concern. The habit is spreading
at an alarming rate among the young generation especially in high schools and higher institutions in Ethiopia.
Students in universities and colleges commonly use khat, cigarette, coffee and other substances to get mental
alertness. The objective of this study was to determine the prevalence and socio-demographic description of
substance use and its effect on academic achievement of students in Jimma University.
METHODS: A cross sectional study was conducted among 248 sampled Medical and health officer students from
September 16 to 20, 2008 using stratified random sampling method. Data were collected using self-administered
structured questionnaire and analyzed using SPSS for Windows version 16. Statistical association was done when
appropriate and level of significance was taken at 5%.
RESULt: Out of 248 sampled subjects, 239 responded giving a response rate of 96.4%. Of these 207 (86.6%) were
males, 115 (48.1%) Oromos, 129 (54.0%) Orthodox Christian, 214 (89.5) in the age group between 20-24 years, and
152 (63.6%) medical students. The mean age of the study subjects was 23 (±1.6) years. The current prevalence of
khat chewing was 33.1%. More males (37.2%) than females, Muslims (71.8%) than other religions, Oromos
(40.9%) than other ethnic group, age group 25 - 30 (86.7%) more than other age groups and final year medical
students (61.5%) than other class years were found to be khat chewers. The current prevalence of cigarette
smoking, alcohol intake and coffee drinking were found to be 21.3%, 36.4%, and 87.9%, respectively. About 68% of
the chewers were smoking cigarette during khat chewing. Eighty eight percent of chewers drink coffee. Forty
percent of them used to take alcohol after khat chewing and 8.9% of the chewers took other substances like
hashish, diazepam and shisha during chewing. Khat chewing had a significant association with high income
(p<0.001), with smoking habit (p<0.001) and with coffee drinking habit (p<0.05). There was statistically significant
difference (p<0.05) between the mean CGPA of chewers (2.77± 0.43) and non-chewers (2.89±0.40); smokers
(2.70±0.45) and non-smokers (2.9±0.4); alcohol users (2.77±0.44) and non-users (2.9±0.4). But no remarkable
difference is seen between the mean CGPA coffee users and non users (p = 0.439, 95% CI [0.23- 0.01]).
CONCLUSION: The current prevalence of different substance use was found to be high. Sex, age, religion and
income have shown significant association with the habit of khat chewing, cigarette smoking, coffee usage and
alcohol intake. This study also showed that khat chewing, smoking and alcohol intake have a significant negative
influence on academic achievements of university students.
KEY WORDS: Prevalence, Khat, Cigarette, alcohol, coffee, academic achievement, Jimma.
INTRODUCTION
Substance use and associated problems are of current
global concern. It has become an epidemic in some parts
of the African region with adolescents being the main
victims of health problems due to substance addiction
(1). The common substances abused in most African
countries including Ethiopia are alcohol, tobacco,
cannabis or marihuana and khat (2, 3). Reports showed
that these substances are widely used among students of
Ethiopia both in colleges and high schools (4).
1---------------------------------------------------
2
Department of Physiology, Medical School, Jimma University), P.O. Box 378, e-mail: andualemm2000@gmail.com
Telephone: 0912051945 or 0471 110118
3
Department of Ophthalmology, Medical School, Jimma University)
2
Corresponding author
Ethiop J. Health Sci Vol. 19, No. 3 November 2009
156
Khat (Catha edulis Forsk, Celastriaceae family) is an
evergreen flowering tree or shrub, widely cultivated in
East Africa both for domestic usage and for
commercial purposes (5). Catha edulis Now-a- days, it
is referred to khat in literatures consistently (6). In the
USA, khat is classified as a schedule IV substance and
cathinone classified as a schedule I substance by the
Drug enforcement agency (4, 5).
Khat contains a substance that stimulates the CNS.
The key constituent of khat responsible for its euphoric
effect is called cathine or norseudoephedrine (7, 8).
Another compound with a powerful CNS stimulant
termed as cathinone (a-aminopropiophenone) (10).
Besides the khatmines, several others compounds have
been isolated from khat. These nutrients include
ascorbic acid, β-carotene, calcium and iron, which
constitute 161 mg, 1.8 mg, 290 mg and 18.5 mg per
100g of fresh consumable leave of khat respectively (9,
10).
Studies suggested that cathinone has positive
inotropic and chronotropic effect on heart, a pressor
effect on arteries, increases blood pressure, respiratory
rate and metabolic rate transiently (3, 6). Reduced
birth weight and inhibition of lactation have been
reported in khat chewing mothers, possibly resulting
from increased dopamine production (7, 13). Regular
khat chewing is a predisposing risk factor for gastritis
and peptic ulcer disease, mental illness, cardiac
arrhythmia, tooth decay and constipation (15).
Contrary to the popular belief that khat chewing helps
students to concentrate while studying, a study conduct
in Jimma University revealed that chewers have lower
academic achievements than non-chewers (11, 12).
Smoking accounts about 10% of deaths world wide,
mainly through cancer especially lung cancer, of which
about 90% of cases are smoking related, ischemic heart
disease and chronic bronchitis (13). Smoking in
pregnancy reduces birth weight and retards child hood
development. It also increases abortion and prenatal
mortality (14). Tobacco products are used primarily to
stimulate the nervous system and to get mental
alertness and to improve memory (16).
Alcoholism is an international problem and had
touched every corner of the world, both developed and
developing countries (14, 16). Physical effects seen in
sexual activity with excessive use of alcohol is
degeneration and dysfunction of sexual glands though
a smaller amount can lower inhibition and make the
person more relaxed and more apt or eager to engage
in social and sexual activity (17). There is direct
relationship between heavy alcohol drinking and
hypertension (15).
Long-term alcohol use cause liver disease,
progression to cirrhosis and liver failure. It also results
in neurological degeneration resulting in dementia and
peripheral neuropathies (19). Excessive consumption
in pregnancy causes impaired fetal development,
associated with small size, abnormal facial
development and other physical abnormalities and
mental retardation (16, 20). Thus, these and other
abused substance in addition to the above described
health problems they cause potential socio-economic
problems to support their habit of drugs and these
abused substances make addicted individuals to
commit criminal activities (18, 21, 22). Studies done
among university students reported that significant
number of students consume khat, coffee and other
substances to increase concentration, alertness and to
keep awake for study during exam periods. However,
this period of stimulation lasts for approximately 3
hours; a depressive phase, including insomnia, malaise,
and a lack of concentration occur as latter effects (2,
8). Thus, the main aim of the present study is, to
determine the magnitude and effect of substance use
on academic performance of students.
SUBJECTS AND METHODS
A cross sectional study was conducted in Jimma
University, Jimma from August 10-September 14,
2008 among sampled medical and health officer
students using self-administered questionnaire.
The required sample size was estimated using formula
for single population proportion with 95% confidence
coefficient and considering the habit of khat chewing
of 30%.
The sampled students were recruited using
multistage sampling techniques based on their
disciplines (health officer and medicine), list in each
class year, and proportion of students in each class
year. Samples were proportionally allocate first the
two disciplines and then years of training. Subjects
were then selected by systematic random sampling
from each class year. The sampling sample size was
allocated to each school and class year as follows:
Effect of Substance Use on Academic Achievement of Health Officer Kalayu M. et al
157
Source population (N = 1079)
Figure 1. A tree showing sample allocation.
A structured questionnaire modified from WHO format
was utilized to collect data from the sampled study
population. The questionnaire included variables like
khat chewing habit with use of other substances, health
risks, peer pressure, attitude towards substance use,
cumulative Grade point average (CGPA) and socio-
demographic characteristics.
Data was collected using self administered
structured questionnaire, where students were asked to
respond genuinely to study variables including their
CGPA. The questionnaire was pre-tested on ten
randomly selected medical students who were excluded
from the study.
After checking the collected data for completeness,
it was analyzed using SPSS for Windows version 16.0.
Statistical significance testing was done and level of
significance was taken at 5%. Independent student t-test
and two-way ANOVA were employed to compare
variables when appropriate.
The study was approved by the Medical Science
Faculty of Jimma University. Informed consent was
taken from the study subjects during the data collection
and participation was totally voluntary. Confidentiality
regarding their habit and CGPA was kept unanimously.
The following definitions were used for the study.
Substance: any of the drugs used by subjects such as
khat, tobacco, coffee or alcohol
Substance abuse: Persistent or sporadic extensive use of
drugs in consistent or unrelated to acceptable medical
practice.
Life time prevalence of chewing/ smoking/ alcohol
use: the proportion of the study population who had ever
chewed khat/smoked/drunk in their lifetime.
Current prevalence of chewing/ smoking/ alcohol use:
the proportion of the study population who are chewing
khat/smoking / drinking in the last 30 days preceding the
study time.
Previous use: history of khat/ cigarette /alcohol use in
lifetime but not in the past 30 days.
Habitual use: refers to use of khat on a daily or more
frequently, otherwise referred as occasional use
Heavy smoking: smoking more than 10 cigarette per day
Substance abuse: Persistent or sporadic extensive use of
drugs in consistent or unrelated to acceptable medical
practice.
RESULT
Out of 248 sampled subjects, 239 responded giving a
response rate of 96.4% but nine questionnaires were
incomplete and so only 230 analyzed. The mean age was
23(±1.6) years. Two hundred seven (86.6%) of the
respondents were males, 115 (48.1%) Oromo, 129
(54.0%) Orthodox Christian, 214(89.2 %) in the age
group of 20-24 years and 151(63.2%) of the students
came from rural area (Table 1).
27
Year II Year III Year IV Year V interns
39 28 38 22 29
Year II
32
Health
officers (N
1
= 398)
Medical
Students
(N
2
= 681)
n
1
=92
n
2
=156
Year III Year IV
33
Ethiop J. Health Sci Vol. 19, No. 3 November 2009
158
Table 1. Prevalence and Socio-demographic characteristics of khat chewing in medical and health officer students of
JU, Southwestern Ethiopia, 2008
** These rows are not included in chi-square calculation as the cells contain expected values less than 5.
¥ Others include Catholic, Jehovah, Adventist
The current prevalence of khat chewing was 33.1%.
More khat use was seen among males (37.2%), Muslims
(71.8%), Oromos (40.9%), students in the age group 25 -
30 (86.7%), medical students (58%) and final year
medical students (61.5%). Thirty eight (48.1%) of the
Chewers smoke cigarette, 70 (88.6%) drank coffee and
7(8.9%) take other substances like hashish, diazepam and
shisha during chewing. Twenty (25.3%) reported to
drink alcohol after khat chewing. Twenty three (76.7%)
of the respondents who were getting >500Birr per month
were khat chewers (Table 1).
Among khat chewers 40 (50.6%) of them were
daily chewers and 22 (27.8%) of them have been
chewing for 2-4 years before the study. Twenty three
(29.1%) of the chewers consume khat that costs 15-20
Birr, 26 (32.9 %), spent more than four hours per session
(Table 2). Forty seven (59.5%) were from khat chewing
families.
Variables
Population
(n = 239)
Khat chewers
(n = 79)
Non
chewers
(n = 160)
X
2
P
-
value
No (%)
No (%)
No (%)
Sex
Male
Female
207 (86.6)
32 (13.4)
77 (37.2)
130 (62.8)
12.0
0.001
2 (6.2)
30 (93.8)
15
-
19**
10 (4.2)
2 (20.0)
8 (80)
20
-
24
214 (89.5)
64 (30.0)
150 (70.0)
25
-
30
15 (6.3)
13 (86.7)
2 (1.3)
Religion
Orthodox
129 (54.0)
30 (23.3)
99 (76.7)
34.51
<0.001
Muslim
39 (16.3)
28 (71.8)
11 (27.2)
Protestant
47 (19.7)
11 (23.4)
36 (75.6)
Others ¥
24 (10)
10 (41.7)
14 (58.3)
Ethnicity
Oromo
115 (48.1)
47 (40.9)
68 (59.1)
3.94
0
.1395
Amhara
71 (29.7)
20 (28.2)
51 (71.8)
Tigrie
25 (10.4)
7 (28.0)
18 (72.0)
Gurage **
14 (5.9)
2 (14.3)
12 (85.7)
Other **
14 (5.9)
3 (21.4
11 (78.6)
Field of
study
Medical
152 (63.6)
57 (37.5)
95 (62.5)
3.2
0.0736
Health officer
8
7 (36.4)
22 (25.3)
65 (74.7)
Income/mn
< 100
100 (41.8)
25 (25.0)
75 (75)
29.77
<0.0001
100
-
500
109 (45.6)
31 (28.4)
78 (71.6)
>500
30 (12.6)
23 (76.7)
7 (23.3)
Place of
upbringing
Rural
151(63.2)
40 (44.3)
48 (55.7)
8.81
0.003
Urban
88 (3
6.8)
39 (26.5)
112 (73.5)
Effect of Substance Use on Academic Achievement of Health Officer Kalayu M. et al
159
Table 2. Pattern of khat chewing in medical and health officer students of JU, Southwestern Ethiopia, 2008.
Chewing pattern(n=79)
Frequency
N
o
%
Chewing frequency
Daily
40
50.6
2
-
3
times a week
20
25.3
Once a week
11
14.0
Occasionally
8
10.1
Duration of chewing
< 1 month
8
10.1
1
-
12 month
10
12.7
1
-
2 year
9
11.4
2
-
4 year
30
38.0
>
4 year
22
27.8
Price of Khat chewed/session (Birr)
5
-
10
21
26.5
10
-
15
17
21.5
15
-
20
23
29.1
> 20
18
22.8
Time spent /session (hours)
< 1
10
12.7
1
-
2
18
22.8
2
-
3
25
31.6
>
4
26
32.9
Additional substances used during and
after Khat
Smoking
38
48.1
Coffee
70
88.6
Alcohol
20
25.3
*Other
7
8.9%
*Other: “hashish”, ”shisha” and diazepam
Relief from academic stress 41(51.8%), for relaxation 27
(34.1%) and socialization 17 (21.5%) were among the
reasons for khat chewing. Thirty six (46%) of the
chewers believed that they can stop chewing in the future
and out of these 23 (59.0%) said they will stop after
graduation. All of the respondents said that khat chewing
has health risk. Sleep disturbance 177 (74.0%),
psychosis 167 (70%) and PUD 100 (41.8%) were few
among others health problems reported by respondents,
considered to be the result of khat Chewing.
Table 4. Association among khat chewing, cigarette smoking alcohol and coffee usage in medical and health officer
students of JU, Southwestern Ethiopia, 2008
Variables
Khat
X
2
P-value
chewers
Non chewers
Total
Smoking
Yes
38
13
51
48
< 0.001
No
41
147
188
Coffee usage
Yes
76
134
210
10
< 0.05
No
3
26
29
Alcohol intake
Yes
31
5
36
No
48
107
155
34.39
< 0.001
Ethiop J. Health Sci Vol. 19, No. 3 November 2009
160
The prevalence of cigarette smoking was 21.3%.
Cigarette smoking was common among males (23.6%),
age group 25-30 years 9(60%), Muslims 16(41%),
Oromo 27(23.5%), and those from urban 27(30.7%) were
smokers. Among the smokers 11(21.6%) smoked greater
than nine cigarettes, 22(43.1%) smoked 4-9 cigarettes
and 14(27.5%) smoked 1-3 cigarettes per day. Of the
total smokers, 20(33.9%) used to smoke for the last 2-4
years and 31(52.5%) of the smokers said that they will
stop smoking in the future. Cigarette smoking has a
positive association with age, sex, religion, income and
place of up bringing (p<0.05). But no significant
association of cigarette smoking was observed with
ethnicity and field of study (p>0.05) (Table 3). Almost
all participants cited that cigarette smoking is a risk for
lung cancer (96.7%), hypertension (71.9 %) and coronary
artery disease (68.2%). As shown in figure 2, 58.6% of
medical interns and 50.0% of fifth year medical students
were found to be khat chewers than the other class years.
The prevalence of alcohol intake was 36.4%.
Alcohol intake was greater in males 81(39.1%), age
group 25-30 years 10 (61.5%), Orthodox 55(42.6%),
Tigrie 15(60.0%), those who earned >500 Birr/month
16(53.4%) and those from urban 37(42.0%). Age, sex
and ethnicity were significantly associated with alcohol
drinking (p < 0.05).
Most of the students 181(87.4%) drink at least one
cup of coffee per day. Hundred (47.6%), 78 (37.1%), 23
(11.0%) and 9 (4.3%) of them drink 1, 2, 3 and 4 cups
per day, respectively. There statistically associated
variable with coffee drinking, while khat chewing was
significantly associated with smoking, coffee drinking
and alcohol intake (p < 0.05) (Table 4).
Table 3. Prevalence and Socio-demographic characteristics of cigarette smoking in medical and health officer
students of JU, Southwestern Ethiopia, 2008
variables
Population
(239)
Smokers
(51)
Non smokers
(188)
X
2
P
-
value
No (%)
No (%)
No (%)
Sex
Male
207 (86.6)
49 (23.6)
1
58 (76.3)
4.03
0.0447
Female
32 (13.4)
2 (6.2)
30 (93.8)
15
-
19 **
4 (1.6)
0
4 (100.0)
7.21
0.0072
Age
20
-
24
224 (92.1)
42 (19.1)
178 (80.9)
25
-
30
15 (6.3)
9 (60)
6 (40)
Religion
Orthodox
129 (54.0)
23 (17.8)
106 (82.2)
13.47
0.00012
Muslim
39 (16.3)
16 (41.0)
23 (59.0)
Protestant
47 (19.7)
5 (10.7)
42 (89.3)
Others
24 (10)
7 (29.2)
17 (70.8)
Ethnicity
Oromo
115 (48.1)
27 (23.5)
88 (76.5)
1.02
0.6005
Amhara
71 (29.7)
12 (16.9)
59 (83.1)
Tigrie
25 (10.4)
5 (20.0)
20 (80.0)
Gurage **
14 (5.9)
3 (21.4)
11 (78.6)
Other **
14 (5.9)
4 (28.6)
10 (71.4)
Field of study
Medical
152 (63.6)
38 (25.0)
114 (75.0)
2.76
0.0966
HO
87 (36.4)
13 (15.0)
74 (85.0)
Income
< 100
100 (41.8)
17 (17.0)
83 (83.0)
10.05
0.0066
100
-
5
00
109 (45.6)
21 (19.3)
88 (80.7)
>500
30 (12.6)
13 (43.4)
17 (56.6)
Place of
upbringing
Rural
151 (63.2)
24 (15.9)
127 (84.1)
6.39
0.0115
Urban
88 (36.8)
27 (30.7)
61 (69.3)
** These rows are not included in chi-square calculation as the cells contain expected values less than 5.
Out of the total respondents 94(39.3%) mentioned that
use of substance helped them for better academic
achievement. Coffee 48 (58.5%), khat 39 (48.0%),
cigarette 5 (6.0%) and alcohol 2 (2.4%) were mentioned
to help their academic achievement.
Effect of Substance Use on Academic Achievement of Health Officer Kalayu M. et al
161
56
12
40
15
41
24
11
11
12
17
0
10
20
30
40
50
60
70
Year II Year III Year IV Year V Interns
Class Year
Frequency of chewers and non
chewers
Non-Chewers
Chewers
Table 5. Association among Khat chewing, cigarette smoking, coffee usage with academic performance (CGPA) in
medical and health officer students of JU, Jimma, Southwestern Ethiopia, Sept.2008
Substance use
Mean
CGPA ± SD
t
-
test for equality of means
t
p-value
95% confidence internal
of the difference
Mean
difference
Lower
Upper
Khat chewing
Yes
2.77
± 0.43
2.32
0.021
0.13
0.246
0.020
No
2.89 ± 0.4
Cigarette smoking
Yes
2.
70 ± 0.45
2.94
0.004
0.20
0.320
0.06
No
2.90 ± 0.40
Alcohol intake
Yes
2.77 ± 0.44
2.41
0.016
0.13
0.245
0.025
No
2.90 ± 0.40
Coffee usage
Yes
2.85 ± 041
0.78
0.439
0.06
0.229
0.009
No
2.91 ± 0.47
Significant difference has been seen in the mean CGPA
of khat chewers versus non chewers (p = 0.021, 95%CI
0.246 and 0.02); smokers versus nonsmokers (p = 0.004,
95%CI 0.32 and 0.06) and the mean CGPA of those who
drink alcohol versus non users (p = 0.016, 95%CI 0.245
and 0.025. But no remarkable difference was seen
between the mean CGPA coffee users and non users (p =
0.439, 95%CI 0.229 and 0.009) (Table 5).
DISCUSSION
The prevalence of khat chewing among medical and
health officer students was 33.1% which is almost
comparable to the one that was reported for Jimma
University students 24.79% (24).
Similar studies among pharmacy and technology
students of Addis Ababa University in 2004(13) and
college students of Northwest Ethiopia in 2002 (20)
found prevalence of khat chewing 14.4% and 17.5%,
respectively which are lower than the current finding.
These could be explained by the availability of khat,
social acceptance to the habit and study time difference
which may contribute to the higher prevalence among JU
medical and health officer students than those in North
West Ethiopia and Addis Ababa University.
This study showed that the habit of khat chewing
was higher in males than females, which is in line with
research findings reported for Jimma University students
in 2004(24). This could be because females are culturally
more restricted than males.
In this study khat chewing has shown significant
association with religion and Muslim students were
found to be khat chewers as compared with students of
other religion. The possible explanation could be
because the habit of khat chewing is socially accepted
among Muslim communities. Thus, Muslim students
may adopt the habit from their society. This finding is
Fig. 2:
Distribution of chat chewing in relation to class year among medical and health officer
students of Jimma University, Southwest Ethiopia, 2008.
Ethiop J. Health Sci Vol. 19, No. 3 November 2009
162
supported by similar studies done in Jimma University
(24), Jimma town (12) and Butajira (1).
In the present study, ethnicity and khat chewing
have shown significant association. More Students of
Oromo ethnic group were found to be chewers than other
ethnic backgrounds. The possible reason could be that
khat is cultivated abundantly in Oromia region and the
society in this area might use it for different purposes and
students may have learned the habit from their
community.
In this study a significant association was found
between smoking and sex, income, religion and place of
up bringing. This is because due to cultural influence on
females and the high income.
Habits of khat chewing and smoking have a strong
association with monthly income. Most of the students
whose monthly income >500 birr were found to be
chewers and smokers compared to those with lower
income. This indicates that having money encourages
students to develop new habits like khat chewing,
cigarette smoking.
The prevalence of alcohol in take in this study was
36.4% which is comparable with that of pharmacy and
technology students of Addis Ababa University (13).
More than half of respondents who had sexual contact
following use of substance
There was statistically significant difference
between the mean CGPA of chewers and non-chewers;
smokers and non-smokers ; alcohol users and non-users
This finding is in agreement with other studies (25). This
shows that substance use has a negative influence on
academic performance of students. The possible
explanation is that the associated valuable time and
energy wastage for khat ceremony and possibly ‘Mirkana
Chebsi’ despite the fact that khat chewing increases
mental alertness/concentration and keeps students awake
(2, 3).
In conclusion, the current prevalence of different
substance use was found to be high. Sex, age, religion
and income have shown significant association with the
habit of khat chewing, cigarette smoking, coffee usage
and alcohol intake. This study also showed that khat
chewing, smoking and alcohol intake have a significant
negative influence on academic achievements of
university students.
Therefore, Jimma University should teach and
counsel students on advantages and disadvantages of
substance use. Health institution and policy makers
should control the production and distribution of khat,
coffee and tobacco plants. Rules and regulations should
be set by universities/colleges in order to prevent
development of such habits to produce motivated and
hard working students with high academic performance.
ACKNOWLEDGEMENTS
The authors are grateful to the student research program
(SRP) of Jimma University for funding this research
project.
REFERENCES
1. Adam F, Hasselot N. Khat: from traditional
usage to risk of drug addiction. Med. Trop.
Adams Mars, 1994; 25(2): 141-144.
2. Alles GA, Fairchild D. and Jensen M. Chemical
pharmacology of Catha edulis. J. Medic. and
Pharmacological Chemistry, 1986; 3 (2): 323-
352.
3. Amaha M. Clinical aspects of khat (Catha edulis
Forsk): in proceedings of international
symposium of khat, 1983: 77-83.
4. Ermias D. Introductory remarks: the chemical
and pharmacological aspect of khat; in
proceedings of international symposium of khat.
1983; Pp1-4.
5. Fekade A. Challi J. and Tadess M. Khat
chewing among Agaro secondary school
students. Ethiop Med J, 1994; 32: 161-166.
6. Heymann TD. Bhupulan A., et al. Khat chewing
delays gastric emptying of a semi-solid meal.
Aliment Pharmacol Ther, 1995; 9(1): 81-83.
7. Kalman S. Recent progress in khat chemistry:
chemical and pharmacological aspect of khat; in
proceedings of international symposium of khat,
1983: 13-28.
8. Peter K. The pharmacology of khat: in
proceedings of international symposium of khat.
1983: 69-76.
9. Sebsebe D. Botanical aspect of `` khat'' Catha
edulis (Celeastracaese): in chemical and
pharmacological aspect of khat: in proceedings
of international symposium of khat, 1983: 5-13.
10. Wilder P, Mathys K, Brenneisen R, Kalix P, and
Fisch HU. Pharmacodynamics and
pharmacokinetics of khat: a controlled study.
Clin Pharmacol Ther, 1994; 5595: 556-562.
11. Zein AZ. Polydrug abuse among Ethiopian
University students with particular reference to
khat (Catha edulis): in proceedings of
international symposium of khat, 1983: 83-88.
12. Kassaye M, Sheriff H., Fissehaye G, Teklu T.
Drug use among high school students in Addis
Ababa and Butajira. Ethiop J Health Dev, 1999;
13 (3):101-106.
13. Eskinder E, Gedif T. Prevalence of Khat,
cigarette and alcohol use among students of
technology and pharmacy, Addis Ababa
University. Ethiopian pharmaceutical Journal
2004; 24 (2): 116-124.
14. WHO. Expert committee technical report series
smoking and its effect on health. Report of
WHO, Geneva 1983.
Effect of Substance Use on Academic Achievement of Health Officer Kalayu M. et al
163
15. Rang H. Dale M, Pilfer J, Mare P. Drug
dependence and drug abuse, pharmacology 5
th
ed, India, Churchill living stone, 2006:598-599.
16. Kasper L, Faucis, Hanser L, Braur wald E, Etal
(2005). Alcoholism and cigarette smoking.
Harrison’s principle of Internal Medical 16
th
ed,
USA, Mc Graw hill: 2562-60, 2573-2580.
17. Doull J, Kallasenec, Amdur M. Alcoholism and
smoking cigarette. In: Cassarate and Doulls Eds
Toxicology. The basic sciences of poisons. 6
th
ed, USA, MC Graw hill companies, 2001: 250.
18. Roy M, Chacrabory A. smoking and drug abuse
among the newly admitted students of medical
college in west Bengal, Indian Journal of public
Health, 1991;25 (1):42-50.
19. ML Adelhan. Self reported drug abuse among
secondary school students in Nigeria state of
Opan, Sept, 1986.
20. Yigzaw K. Cigarette smoking and khat chewing
among college students in northwest Ethiopia.
Ethiop J Health Dev, 2002; 16(1):9-17.
21. Samson H. Pattern and prevalence of poly drug
abuse among medical and paramedical students
of JIHS. Ethiopian J of Health sci, 1997;
8(1):15.
22. Yeshigeth G, Abraham H. Prevalence and socio
demographic characteristics of khat chewing
and other associated factors with khat use in
Technical and academic staff of JU, Ethiop J
Health Dev, 2004; 18(3):179-184.
23. Asseffa S, Dammene H, Alemayehu G. The
association between substance abuse and HIV
infection among people visiting VCT,
counseling and testing centers in Addis Ababa,
Ethiop J Health Dev, 2005; 19(2); 88-164.
24. Andualem M, Zeleke M. Khat chewing, socio-
demographic characteristics and its effect on
academic performance in Jimma University
students. Ethiop Med J, 2004; 42(2):125-136.
25. Mesfin B, Dereje K.Mesfin k, Fikre E.The
magnitude of Khat use and its association with
health. Ethiop Med J, 2000; 38(1):11-26.
