Mental health problems and related conditions associated with khat use
Of all the included articles, 100 (92.6%) of them used khat use as a predictor variable and the remaining 8 (7.4%) articles [
39‐
46] considered khat use as an outcome variable. Ten different categories of mental health disorders associated with khat chewing are provided in Table
3 and the description of each identified association is provided in the subsequent sub-sections.
Table 3
Mental health disorders associated with khat chewing (n = 108)
Depression, anxiety, stress | 17 | 15.7 |
Non-specific (general) psychological distress | 29 | 26.9 |
Insomnia | 1 | 0.9 |
Mood status | 4 | 3.7 |
Neurocognitive disorder | 8 | 7.4 |
Psychopathy | 2 | 1.8 |
Psychosis | 17 | 15.7 |
Social phobia | 1 | 0.9 |
Substance use disorder | 16 | 14.9 |
Suicidal ideation | 5 | 4.6 |
Other conditions related to mental health* | 8 | 7.4 |
Total
|
108
|
100.0
|
A.
Non-specific psychological distress.
Non-specific psychological distress is the most frequently mentioned mental health problem in connection with khat use, reported in 26.9% of the included studies. The evidence about this association is mixed, with some studies indicating the existence of significant associations and others reporting the absence of such associations [
34,
47,
48][
49]. The lowest reported Adjusted Odds Ratio (AOR) was 2.23 [
50] and the highest AOR was 6.91 [
51]. A hospital-based cross-sectional survey among patients with hypertension reported the absence of an association between psychological morbidity and khat chewing [
48]. Some of the articles indicate that it is not khat in and of itself that is associated with non-specific psychological distress, but rather the frequency of use. For instance, people who use khat regularly or daily had eight times higher chance of experiencing mental distress than those who do not use khat (AOR = 8.122, 95% CI: 1.232–53.551), while people with more moderate use patterns (occasionally and one or more per week) have no significant chance of experiencing non-specific psychological distress than those who do not use khat [
34]. One study found that ‘current use of khat’ is not associated with non-specific psychological distress, while life time prevalence of khat use is associated [
52]. Qualitative findings, on the other hand, suggest that people use khat for the treatment of psychological distress [
53].
Of all the studies within the evidence base, 15.7% explore the association between psychosis and khat chewing. This makes psychosis the specific mental disorder frequently associated with khat chewing. Evaluation of the strength of this evidence shows that 64.7% (11 out of the 17 articles) relied on case report or case series designs, and 58.8% (10 out of the 17 articles) of the studies were conducted among migrants from traditionally khat chewing regions.
C.
Depression, anxiety, and/ or stress.
Depression, anxiety and/or stress are grouped together in this review as several studies address these topics jointly. This category is reported by 15.7% of the articles included in this scoping review.
Several studies show a significant association [
54‐
57], some studies report the absence of such association [
28,
40,
41,
58] and one other study [
59] reports the use of khat for alleviating depression and stress. In a cross-sectional study among university students, khat use was not associated with depression, anxiety, and stress in the univariate analysis [
23]. Another studies among students found that khat chewing is insignificantly related to depression [
40][
41] and stress [
41] after a multivariate logistic regression analysis.
On the other hand, there is also evidence showing that a history of khat chewing is significantly associated with depression, stress and anxiety. Prisoners who chew khat prior to incarceration were about two times more likely to develop depression (AOR = 2.47, 95% CI: 1.049–5.85, P = 0.039) than those who did not chew khat [
57]. Among currently married women (15–49 years old) in rural Ethiopia, frequent khat use is also independently associated with depression (OR = 1.61) [
54]. Among Jimma university staff (Ethiopia), khat chewing was associated with depression (AOR = 4.99, 95% CI: 2.57–9.69), anxiety (AOR = 2.94, 95% CI: 1.52–5.66) and stress (AOR = 2.78, 95% CI: 1.49–5.21) [
55]. Another study shows that it is not just khat use which matters in causing anxiety and depression. The study revealed statistically significant differences in the levels of anxiety (F (2, 15) = 9.64, p < 0.05) and depression (F (2, 15) = 6.34, p < 0.05) among non-chewers, non-dependent khat chewers and dependent khat chewers. After conducting post-hoc multiple comparisons, dependent khat chewers scored significantly higher mean values in both anxiety and depression as compared to non-chewers and non-dependent khat chewers. Non-dependent khat chewers have almost the same mean score for anxiety and depression, as non-chewers [
56].
The functional use of khat to relieve anxieties and depression have also been reported in a mixed method study [
59].
The fourth category of mental disorder associated with the use of khat is substance use disorder. About 15% of the included studies have reported such association. A measurement of khat dependence based on the Drug Abuse Screening Test-10 (DAST-10) among people who use khat shows that 2% reported no problems, and 17.3% reported a low level, 73.6% reported a moderate level and 7.1% reported a substantial level of dependence. The risk of being moderately dependent increases by 4.8 (95.0% CI 1.46–15.78) for daily chewers as compared to irregular chewers [
35]. Assessment of khat use disorders among samples recruited from the general community and university students using DSM-5 criteria shows that 10.5% (95% CI: 7.9–13.9) were categorized as experiencing mild, 8.8% (95% CI: 6.4–12.0) moderate and 54.5% (95% CI 49.6–59.3) severe khat use disorders. Khat use disorder is prevalent among subjects with greater frequency and quantity of khat use [
32].
The use of khat has also been associated with the prevalence of alcohol use disorders and nicotine dependence. Khat chewing was a predictor of alcohol use disorders (AOR = 5.11, 95% CI: 1.60, 16.33) among human immunodeficiency virus-infected patients attending an antiretroviral therapy clinic [
60]. Chewing khat is one of the significant factors associated with an increased prevalence of alcohol use disorders (AOR = 3.26, CI:1.30, 8.15) among university undergraduate students [
61]. Concerning nicotine dependence, the odds of nicotine dependence for people who use khat were three times higher (AOR 3.09, 95% CI:1.206–7.896) when compared to those who do not use khat among adult psychiatric patients [
62]. Similarly, among people with a mental illness, there was a significant association between tobacco dependence and daily khat chewing (AOR = 13.51, 95% CI: 4.27, 42.74), chewing khat 2–3 times per week (AOR = 5.09, 95% CI = 1.37,18.95), or chewing khat once a week (AOR = 4.31, 95%CI: 1.04,17.78) [
63].
Five studies have examined the association between khat use and suicidal ideation. The odds of suicidal ideation were higher among those having a history of khat use [
64‐
66]. A cross-sectional study among khat-chewing mothers attending public health centers in Addis Ababa after child delivery shows that the odds of suicidal ideation were 8.48 higher among those who chew khat as compared to those who do not [
66]. Similarly, a cross-sectional study on suicidal thoughts among university students in Ethiopia found that the odds of suicidal ideation range from 1.78 to 4.46 among khat-chewing students than their non-chewing counterparts [
64,
65].
Neurocognitive disorders have been studied in 7.4% of the studies. People who chew khat scored less in tasks related to cognitive flexibility (which is the ability to adapt and restructure cognitive representations in response to changing situational demands) than those who do not chew khat [
67]. Studies also found a negative effect of khat use on working memory [
67,
68]. Although statistically significant [F(3, 57) = 3.98, p = 0.012], the extent of performance decline seen in people who use khat is modest [
68]. On the other hand, no statistically significant difference [F(3, 57) = 0.819, p = 0.369] is found in the speed of information processing between a group of chronic khat chewers and a non-chewing control group [
68].
The importance of considering the use of other substances has been pronounced in the study of the neuropsychological impacts of khat use [
69]. As compared to the khat-only group and the control group of non-users of khat and cigarettes, the concurrent khat and cigarette users recalled fewer words, had a slowed rate of verbal learning, and demonstrated delayed recall of previously learned verbal material [
69]. The authors suggested that khat use alone may not affect immediate or delayed recall of previously learned words. Post-hoc tests did not show statistically significant differences in performance between non-users of khat and cigarettes, and khat-only users [
69].
A study among chronic khat chewers shows that more deficits in neuropsychological functions are observed among khat chewers than among the non-chewing control group. The study suggests that the effects of khat are moderate and may not be noticeable after the consumption of a low dose [
70].
G.
Others mental health disorders and related conditions.
Under this section, those mental health disorders and related conditions mentioned in less than 5% of the studies are described. Among patients with schizophrenia, the use of khat has been associated with a lesser probability of properly following treatment for the disease. In a retrospective study to assess response to standard anti-psychotic treatment, a significant difference (P < 0.001) in the retention rate of the initial drug was observed among patients who use khat and patients who do not use khat (53.8% vs. 78.4%). Substituting the initial drug mainly due to lack of drug efficacy was significantly higher among moderate and heavy khat chewers than low and mild khat chewers (55% and 49.2% vs. 35.6% and 44.7% respectively, P < 0.001). It is hypothesized that khat could have hampered the response to initial antipsychotic drug treatment [
71]. Concerning quality of life, the use of khat has been associated with a lower mental health component of quality-of-life scores [
72‐
74]. Contrarily, among patients with schizophrenia, patients who use khat had higher scores in the mental health components of quality of life than patients who do not use khat (71.76 vs. 69.59) [
75].
A study has shown that khat is believed to be related to suicidal death. In a case series study of khat-related deaths in the UK, four cases of suicide (three confirmed and one possible cases) due to psychoses caused and/ or worsened by long-term khat consumption have occurred [
76]. Though lifetime khat use is associated with social phobia among college students in univariate analysis, the association was found to be insignificant in a multivariate regression model [
77]. Khat chewing has been associated with sleeping disorders as a result of a pattern of heavy use [
78]. Concerning mood disturbances, people who chew khat complain more frequently about negative affects than non-chewers [
79]. People who chew khat are exposed to higher trait anger and negative responses during stress [
80], and mild dysphoria and sedation after the end of the chewing sessions [
81]. Studies among prisoners in correctional institutions show that inmates with psychopathy had three times higher odds of having a khat use history than those without psychopathy [
46], and high-risk khat chewers were more likely to develop psychopathy than non-risk khat chewers, although the operational definition relating to what constitutes ‘risky use’ is not provided in the study [
82]. Although khat use helps to cope with the side effects of antipsychotic drugs, drowsiness, and hunger among people with schizophrenia, it is also found to increase the risk of relapse and readmission to a psychiatric ward [
20].
Limitations of the studies
This review identified limitations related to study designs, several forms of biases, inability to control confounding variables, and sampling problems.