Introduction: Kratom (Mitragyna speciosa) is a medicinal tree native to Southeast Asia. The present multilevel meta-analysis describes the association between kratom use and the positive and negative indicators of mental health. Methods: A total of thirty-six articles were included in the meta-analysis to examine the associations, using a random-effects model. Results: The pooled effect size showed a very small positive association between kratom use and negative indicators of mental health {r = 0.092, 95% confidence interval (CI) = [0.020, 0.164], p < 0.05}, while no significant association was found with positive indicators of mental health (r = −0.031, 95% CI = [−0.149, 0.087], p > 0.05). Pooled effect sizes of specific mental health outcomes indicated that kratom use showed only a small positive correlation with externalizing disorders (r = 0.201, 95% CI = [0.107, 0.300], p < 0.001). No significant association was found between kratom use and quality of life (r = 0.069, 95% CI = [−0.104, 0.242], p > 0.05) and internalizing disorders (r = −0.001, 95% CI = [−0.115, 0.095], p > 0.05). Multilevel moderator analysis showed that the pooled effect size of the association between kratom use and substance use disorder was stronger in Malaysia (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001), and with the mean age (β1 = −0.035, 95% CI = [−0.055, −0.014], p = 0.003), and the drug profile of those who were not co-using other drugs (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001). Conclusion: The meta-analysis supports the kratom instrumentalization concept, in that a positive gain from kratom consumption can be achieved without any significant adverse associations with mental health.

1.
Hassan
Z
,
Muzaimi
M
,
Navaratnam
V
,
Yusoff
NH
,
Suhaimi
FW
,
Vadivelu
R
, et al
.
From Kratom to mitragynine and its derivatives: physiological and behavioural effects related to use, abuse, and addiction
.
Neurosci Biobehav Rev
.
2013
;
37
(
2
):
138
51
.
2.
Henningfield
JE
,
Wang
DW
,
Huestis
MA
.
Kratom abuse potential 2021: an updated eight factor analysis
.
Front Pharmacol
.
2021
;
12
:
775073
.
3.
Kruegel
AC
,
Grundmann
O
.
The medicinal chemistry and neuropharmacology of kratom: a preliminary discussion of a promising medicinal plant and analysis of its potential for abuse
.
Neuropharmacology
.
2018
;
134
(
Pt A
):
108
20
.
4.
Johnson
LE
,
Balyan
L
,
Magdalany
A
,
Saeed
F
,
Salinas
R
,
Wallace
S
, et al
.
The potential for kratom as an antidepressant and antipsychotic
.
Yale J Biol Med
.
2020
;
93
(
2
):
283
9
.
5.
Leong Bin Abdullah
MFI
,
Singh
D
.
The adverse cardiovascular effects and cardiotoxicity of kratom (mitragyna speciosa korth.): a comprehensive review
.
Front Pharmacol
.
2021b
;
12
:
726003
.
6.
Prevete
E
,
Kuypers
KPC
,
Theunissen
EL
,
Corazza
O
,
Bersani
G
,
Ramaekers
JG
.
A systematic review of (pre)clinical studies on the therapeutic potential and safety profile of kratom in humans
.
Hum Psychopharmacol
.
2022
;
37
(
1
):
e2805
.
7.
Schimmel
J
,
Dart
RC
.
Kratom (mitragyna speciosa) liver injury: a comprehensive review
.
Drugs
.
2020
;
80
(
3
):
263
83
.
8.
Stanciu
CN
,
Gnanasegaram
SA
,
Rader
GL
,
Sharma
A
,
McCurdy
CR
.
What is the kratom overdose risk? A systematic literature review
.
Curr Addict Rep
.
2023
;
10
:
9
28
.
9.
Warner
ML
,
Kaufman
NC
,
Grundmann
O
.
The pharmacology and toxicology of kratom: from traditional herb to drug of abuse
.
Int J Leg Med
.
2016
;
130
(
1
):
127
38
.
10.
Mat
NH
,
Bakar
SNS
,
Murugaiyah
V
,
Chawarski
MC
,
Hassan
Z
.
Analgesic effects of main indole alkaloid of kratom, mitragynine in acute pain animal model
.
Behav Brain Res
.
2023
;
439
:
114251
.
11.
Vicknasingam
B
,
Chooi
WT
,
Rahim
AA
,
Ramachandram
D
,
Singh
D
,
Ramanathan
S
, et al
.
Kratom and pain tolerance: a randomized, placebo-controlled, double-blind study
.
Yale J Biol Med
.
2020
;
93
(
2
):
229
38
.
12.
Bath
R
,
Bucholz
T
,
Buros
AF
,
Singh
D
,
Smith
KE
,
Veltri
CA
, et al
.
Self-reported health diagnoses and demographic correlates with kratom use: results from an online survey
.
J Addict Med
.
2020
;
14
(
3
):
244
52
.
13.
Deebel
NA
,
Scarberry
K
,
O’Connor
CA
,
Dutta
R
,
Matz
E
,
Hanlon
CA
, et al
.
Investigating the impact of kratom (Mitragyna speciosa) use upon male sexual health
.
Res Rep Urol
.
2023
;
15
:
69
76
.
14.
Garcia-Romeu
A
,
Cox
DJ
,
Smith
KE
,
Dunn
KE
,
Griffiths
RR
.
Kratom (Mitragyna speciosa): user demographics, use patterns, and implications for the opioid epidemic
.
Drug Alcohol Depend
.
2020
;
208
:
107849
.
15.
Grundmann
O
,
Veltri
CA
,
Morcos
D
,
Knightes
D
,
Smith
KE
,
Singh
D
, et al
.
Exploring the self-reported motivations of kratom (Mitragyna speciosa Korth.) use: a cross-sectional investigation
.
Am J Drug Alcohol Abuse
.
2022
;
48
(
4
):
433
44
.
16.
Grundmann
O
,
Veltri
CA
,
Morcos
S
,
Smith
KE
,
Singh
D
,
Corazza
O
, et al
.
Correlations of kratom (Mitragyna speciosa Korth.) use behavior and psychiatric conditions from a cross-sectional survey
.
Exp Clin Psychopharmacol
.
2023
;
31
(
5
):
963
77
.
17.
Leong Bin Abdullah
MFI
,
Singh
D
,
Swogger
MT
,
Rahim
AA
,
Vicknasingam
B
.
The prevalence of psychotic symptoms in kratom (Mitragyna speciosa Korth.) Users in Malaysia
.
Asian J Psychiatr
.
2019
;
43
:
197
201
.
18.
Leong Bin Abdullah
MFI
,
Yuvashnee
N
,
Singh
D
.
Effect of regular kratom (Mitragyna speciosa Korth.) use on quality of life of people who use kratom
.
Subst Abus
.
2021
;
42
(
4
):
444
9
.
19.
Saref
A
,
Suraya
S
,
Singh
D
,
Grundmann
O
,
Narayanan
S
,
Swogger
MT
, et al
.
Self-reported prevalence and severity of opioid and kratom (Mitragyna speciosa Korth.) side effects
.
J Ethnopharmacol
.
2019
;
238
:
111876
.
20.
Singh
D
,
Narayanan
S
,
Müller
CP
,
Swogger
MT
,
Chear
NJY
,
Dzulkapli
EB
, et al
.
Motives for using Kratom (Mitragyna speciosa Korth.) among regular users in Malaysia
.
J Ethnopharmacol
.
2019
;
233
:
34
40
.
21.
Singh
D
,
Grundmann
O
,
Murugaiyah
V
,
Rahim
ABM
,
Chawarski
M
,
Balasingam
V
.
Improved sexual functioning of long-term daily users of Mitragyna speciosa (Korth.)
.
J Herb Med
.
2020a
;
19
:
100293
.
22.
Singh
D
,
Narayanan
S
,
Abdullah
MFIL
,
Vicknasingam
B
.
Effects of kratom (Mitragyna speciosa Korth.) in reducing risk-behaviors among a small sample of HIV positive opiate users in Malaysia
.
J Ethn Subst Abuse
.
2020
;
21
(
4
):
1285
95
.
23.
Smith
KE
,
Dunn
KE
,
Grundmann
O
,
Garcia-Romeu
A
,
Rogers
JM
,
Swogger
MT
, et al
.
Social, psychological, and substance use characteristics of U.S. adults who use kratom: initial findings from an online, crowdsourced study
.
Exp Clin Psychopharmacol
.
2022
;
30
(
6
):
983
96
.
24.
Smith
KE
,
Rogers
JM
,
Strickland
JC
.
Associations of lifetime nonmedical opioid, methamphetamine, and kratom use within a nationally representative US sample
.
J Psychoactive Drugs
.
2022
;
54
(
5
):
429
39
.
25.
Cheung
MW
.
A guide to conducting a meta-analysis with non-independent effect sizes
.
Neuropsychol Rev
.
2019
;
29
(
4
):
387
96
.
26.
Cinosi
E
,
Martinotti
G
,
Simonato
P
,
Singh
D
,
Demetrovics
Z
,
Roman-Urrestarazu
A
, et al
.
Following “the roots” of kratom (mitragyna speciosa): the evolution of an enhancer from a traditional use to increase work and productivity in Southeast Asia to a recreational psychoactive drug in western countries
.
BioMed Res Int
.
2015
;
2015
:
968786
.
27.
Singh
D
,
Narayanan
S
,
Vicknasingam
B
.
Traditional and non-traditional uses of Mitragynine (Kratom): a survey of the literature
.
Brain Res Bull
.
2016
;
126
(
Pt 1
):
41
6
.
28.
Singh
D
,
Narayanan
S
,
Vicknasingam
B
,
Prozialeck
WC
,
Smith
KE
,
Corazza
O
, et al
.
The use of kratom (mitragyna speciosa Korth.) among people who Co-use heroin and methamphetamine in Malaysia
.
J Addict Med
.
2022
;
16
(
2
):
223
8
.
29.
Coe
MA
,
Pillitteri
JL
,
Sembower
MA
,
Gerlach
KK
,
Henningfield
JE
.
Kratom as a substitute for opioids: results from an online survey
.
Drug Alcohol Depend
.
2019
;
202
:
24
32
.
30.
Müller
E
,
Hillemacher
T
,
Müller
CP
.
Kratom instrumentalization for severe pain self-treatment resulting in addiction - a case report of acute and chronic subjective effects
.
Heliyon
.
2020
;
6
(
7
):
e04507
.
31.
Müller
E
,
Hillemacher
T
,
Müller
CP
.
Kratom use for depression/anxiety self-management: challenges during the COVID-19 pandemic - a case report
.
Heliyon
.
2021
;
7
(
5
):
e07039
.
32.
Flores-Bocanegra
L
,
Raja
HA
,
Graf
TN
,
Augustinović
M
,
Wallace
ED
,
Hematian
S
, et al
.
The chemistry of kratom [Mitragyna speciosa]: updated characterization data and methods to elucidate indole and oxindole alkaloids
.
J Nat Prod
.
2020
;
83
(
7
):
2165
77
.
33.
Eastlack
SC
,
Cornett
EM
,
Kaye
AD
.
Kratom-Pharmacology, clinical implications, and outlook: a comprehensive review
.
Pain Ther
.
2020
;
9
(
1
):
55
69
.
34.
Prozialeck
WC
,
Jivan
JK
,
Andurkar
SV
.
Pharmacology of kratom: an emerging botanical agent with stimulant, analgesic and opioid-like effects
.
J Am Osteopath Assoc
.
2012
;
112
(
12
):
792
9
.
35.
Raffa
RB
,
Pergolizzi
JV
,
Taylor
R
,
Ossipov
MH
;
NEMA Research Group
.
Nature’s first “atypical opioids”: kratom and mitragynines
.
J Clin Pharm Ther
.
2018
;
43
(
3
):
437
41
.
36.
Kruegel
AC
,
Gassaway
MM
,
Kapoor
A
,
Váradi
A
,
Majumdar
S
,
Filizola
M
, et al
.
Synthetic and receptor signaling explorations of the mitragyna alkaloids: mitragynine as an atypical molecular framework for opioid receptor modulators
.
J Am Chem Soc
.
2016
;
138
(
21
):
6754
64
.
37.
Obeng
S
,
Wilkerson
JL
,
León
F
,
Reeves
ME
,
Restrepo
LF
,
Gamez-Jimenez
LR
, et al
.
Pharmacological comparison of mitragynine and 7-hydroxymitragynine: in vitro affinity and efficacy for μ-opioid receptor and opioid-like behavioral effects in rats
.
J Pharmacol Exp Ther
.
2021
;
376
(
3
):
410
27
.
38.
Chear
NJ
,
León
F
,
Sharma
A
,
Kanumuri
SRR
,
Zwolinski
G
,
Abboud
KA
, et al
.
Exploring the chemistry of alkaloids from Malaysian Mitragyna speciosa (kratom) and the role of oxindoles on human opioid receptors
.
J Nat Prod
.
2021
;
84
(
4
):
1034
43
.
39.
Kruegel
AC
,
Uprety
R
,
Grinnell
SG
,
Langreck
C
,
Pekarskaya
EA
,
Le Rouzic
V
, et al
.
7-Hydroxymitragynine is an active metabolite of mitragynine and a key mediator of its analgesic effects
.
ACS Cent Sci
.
2019
;
5
(
6
):
992
1001
.
40.
Mukhopadhyay
S
,
Gupta
S
,
Wilkerson
JL
,
Sharma
A
,
McMahon
LR
,
McCurdy
CR
.
Receptor selectivity and therapeutic potential of kratom in substance use disorders
.
Curr Addict Rep
.
2023
;
10
(
2
):
304
16
.
41.
Kamble
SH
,
León
F
,
King
TI
,
Berthold
EC
,
Lopera-Londoño
C
,
Siva Rama Raju
K
, et al
.
Metabolism of a kratom alkaloid metabolite in human plasma increases its opioid potency and efficacy
.
ACS Pharmacol Transl Sci
.
2020
;
3
(
6
):
1063
8
.
42.
Yusof
SR
,
Mohd Uzid
M
,
Teh
EH
,
Hanapi
NA
,
Mohideen
M
,
Mohamad Arshad
AS
, et al
.
Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studies
.
Addict Biol
.
2019
;
24
(
5
):
935
45
.
43.
Wilson
LL
,
Harris
HM
,
Eans
SO
,
Brice-Tutt
AC
,
Cirino
TJ
,
Stacy
HM
, et al
.
Lyophilized kratom tea as a therapeutic option for opioid dependence
.
Drug Alcohol Depend
.
2020
;
216
:
108310
.
44.
Wilson
LL
,
Chakraborty
S
,
Eans
SO
,
Cirino
TJ
,
Stacy
HM
,
Simons
CA
, et al
.
Kratom alkaloids, natural and semi-synthetic, show less physical dependence and ameliorate opioid withdrawal
.
Cell Mol Neurobiol
.
2021
;
41
(
5
):
1131
43
.
45.
Singh
D
,
Narayanan
S
,
Grundmann
O
,
Dzulkapli
EB
,
Vicknasingam
B
.
Effects of kratom (mitragyna speciosa korth.) use in regular users
.
Subst Use Misuse
.
2019c
;
54
(
14
):
2284
9
.
46.
Hemby
SE
,
McIntosh
S
,
Leon
F
,
Cutler
SJ
,
McCurdy
CR
.
Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynine
.
Addict Biol
.
2019
;
24
(
5
):
874
85
.
47.
Kamble
SH
,
Sharma
A
,
King
TI
,
León
F
,
McCurdy
CR
,
Avery
BA
.
Metabolite profiling and identification of enzymes responsible for the metabolism of mitragynine, the major alkaloid of Mitragyna speciosa (kratom)
.
Xenobiotica
.
2019
;
49
(
11
):
1279
88
.
48.
Kamble
SH
,
Berthold
EC
,
Kanumuri
SRR
,
King
TI
,
Kuntz
MA
,
León
F
, et al
.
Metabolism of speciociliatine, an overlooked kratom alkaloid for its potential pharmacological effects
.
AAPS J
.
2022
;
24
(
5
):
86
.
49.
Todd
DA
,
Kellogg
JJ
,
Wallace
ED
,
Khin
M
,
Flores-Bocanegra
L
,
Tanna
RS
, et al
.
Chemical composition and biological effects of kratom (Mitragyna speciosa): in vitro studies with implications for efficacy and drug interactions
.
Sci Rep
.
2020
;
10
(
1
):
19158
.
50.
Suhaimi
FW
,
Yusoff
NHM
,
Hassan
R
,
Mansor
SM
,
Navaratnam
V
,
Müller
CP
, et al
.
Neurobiology of Kratom and its main alkaloid mitragynine
.
Brain Res Bull
.
2016
;
126
(
Pt 1
):
29
40
.
51.
Yusoff
NHM
,
Mansor
SM
,
Müller
CP
,
Hassan
Z
.
Opioid receptors mediate the acquisition, but not the expression of mitragynine-induced conditioned place preference in rats
.
Behav Brain Res
.
2017
;
332
:
1
6
.
52.
Grundmann
O
.
Patterns of Kratom use and health impact in the US-Results from an online survey
.
Drug Alcohol Depend
.
2017
;
176
:
63
70
.
53.
Smith
KE
,
Rogers
JM
,
Schriefer
D
,
Grundmann
O
.
Therapeutic benefit with caveats? analyzing social media data to understand the complexities of kratom use
.
Drug Alcohol Depend
.
2021
;
226
(
108879
):
108879
.
54.
Singh
D
,
Yeou Chear
NJ
,
Narayanan
S
,
Leon
F
,
Sharma
A
,
McCurdy
CR
, et al
.
Patterns and reasons for kratom (Mitragyna speciosa) use among current and former opioid poly-drug users
.
J Ethnopharmacol
.
2020
;
249
:
112462
.
55.
Vicknasingam
B
,
Narayanan
S
,
Beng
GT
,
Mansor
SM
.
The informal use of ketum (Mitragyna speciosa) for opioid withdrawal in the northern states of peninsular Malaysia and implications for drug substitution therapy
.
Int J Drug Pol
.
2010
;
21
(
4
):
283
8
.
56.
Assanangkornchai
S
,
Muekthong
A
,
Sam-Angsri
N
,
Pattanasattayawong
U
.
The Use of Mitragynine speciosa (“Krathom”), an addictive plant, in Thailand
.
Subst Use Misuse
.
2007
;
42
(
14
):
2145
57
.
57.
Ahmad
K
,
Aziz
Z
.
Mitragyna speciosa use in the northern states of Malaysia: a cross-sectional study
.
J Ethnopharmacol
.
2012
;
141
(
1
):
446
50
.
58.
Suwanlert
S
.
A study of kratom eaters in Thailand
.
Bull Narc
.
1975
;
27
(
3
):
21
7
.
59.
Saingam
D
,
Assanangkornchai
S
,
Geater
AF
,
Balthip
Q
.
Pattern and consequences of krathom (Mitragyna speciosa Korth.) use among male villagers in southern Thailand: a qualitative study
.
Int J Drug Pol
.
2013
;
24
(
4
):
351
8
.
60.
Müller
CP
,
Schumann
G
.
Drugs as instruments: a new framework for non-addictive psychoactive drug use
.
Behav Brain Sci
.
2011
;
34
(
6
):
293
310
.
61.
Singh
D
,
Müller
CP
,
Vicknasingam
BK
,
Mansor
SM
.
Social functioning of kratom (mitragyna speciosa) users in Malaysia
.
J Psychoactive Drugs
.
2015
;
47
(
2
):
125
31
.
62.
Müller
CP
,
Schumann
G
,
Rehm
J
,
Kornhuber
J
,
Lenz
B
.
Self-management with alcohol over lifespan: psychological mechanisms, neurobiological underpinnings, and risk assessment
.
Mol Psychiatry
.
2023
;
28
(
7
):
2683
96
.
63.
Leong Abdullah
MFI
,
Tan
KL
,
Narayanan
S
,
Yuvashnee
N
,
Chear
NJY
,
Singh
D
, et al
.
Is kratom (Mitragyna speciosa Korth.) use associated with ECG abnormalities? Electrocardiogram comparisons between regular kratom users and controls
.
Clin Toxicol
.
2021
;
59
(
5
):
400
8
.
64.
Leong Bin Abdullah
MFI
,
Tan
KL
,
Mohd Isa
S
,
Yusoff
NS
,
Chear
NJY
,
Singh
D
.
Lipid profile of regular kratom (Mitragyna speciosaKorth.) users in the community setting
.
Plos One
.
2020
;
15
(
6
):
e0234639
.
65.
Jasim
RK
,
Hassan
Z
,
Singh
D
,
Boyer
E
,
Gam
L-H
.
Characterization of urinary protein profile in regular kratom (Mitragyna speciosa korth.) users in Malaysia
.
J Addict Dis
.
2022
;
40
(
2
):
235
46
.
66.
Leong Bin Abdullah
MFI
,
Singh
D
.
Assessment of cardiovascular functioning among regular kratom (mitragyna speciosa korth) users: a case series
.
Front Pharmacol
.
2021
;
12
:
723567
.
67.
Singh
D
,
Müller
CP
,
Murugaiyah
V
,
Hamid
SBS
,
Vicknasingam
BK
,
Avery
B
, et al
.
Evaluating the hematological and clinical-chemistry parameters of kratom (Mitragyna speciosa) users in Malaysia
.
J Ethnopharmacol
.
2018
;
214
:
197
206
.
68.
Singh
D
,
Murugaiyah
V
,
Hamid
SBS
,
Kasinather
V
,
Chan
MSA
,
Ho
ETW
, et al
.
Assessment of gonadotropins and testosterone hormone levels in regular Mitragyna speciosa (Korth.) users
.
J Ethnopharmacol
.
2018
;
221
:
30
6
.
69.
Singh
D
,
Chye
Y
,
Suo
C
,
Yücel
M
,
Grundmann
O
,
Ahmad
MZ
,
Vicknasingam
B
.
Brain magnetic resonance imaging of regular kratom (Mitragyna speciosa Korth.) users: a preliminary study
.
Malays J Med Heal Sci
.
2018
;
14
(
Suppl 1
):
65
70
.
70.
Singh
D
,
Damodaran
T
,
Prozialeck
WC
,
Grundmann
O
,
Karunakaran
T
,
Vicknasingam
B
.
Constipation prevalence and fatigue severity in regular kratom (Mitragyna speciosa Korth.) users
.
J Substance Use
.
2019
;
24
(
3
):
233
9
.
71.
Singh
D
,
Narayanan
S
,
Grundmann
O
,
Chear
NJY
,
Murugaiyah
V
,
Hamid
SBS
,
Balasingam
V
.
Long-term effects of kratom [mitragyna speciosa] use
.
Mal J Med Health Sci
.
2020
;
16
(
4
):
64
72
.
72.
Trakulsrichai
S
,
Sathirakul
K
,
Auparakkitanon
S
,
Krongvorakul
J
,
Sueajai
J
,
Noumjad
N
, et al
.
Pharmacokinetics of mitragynine in man
.
Drug Des Devel Ther
.
2015
;
9
:
2421
9
.
73.
Singh
D
,
Müller
CP
,
Vicknasingam
BK
.
Kratom (Mitragyna speciosa) dependence, withdrawal symptoms and craving in regular users
.
Drug Alcohol Depend
.
2014
;
139
:
132
7
.
74.
Singh
D
,
Narayanan
S
,
Müller
CP
PhD
,
Vicknasingam
B
,
Yücel
M
PhD
,
Ho
ETW
, et al
.
Long-term cognitive effects of kratom (mitragyna speciosa korth.) use
.
J Psychoactive Drugs
.
2019b
;
51
(
1
):
19
27
.
75.
Manwell
LA
,
Barbic
SP
,
Roberts
K
,
Durisko
Z
,
Lee
C
,
Ware
E
, et al
.
What is mental health? Evidence towards a new definition from a mixed methods multidisciplinary international survey
.
BMJ open
.
2015
;
5
(
6
):
e007079
.
76.
Herrman
H
,
Saxena
S
,
Moodie
R
.
Promoting mental health: concepts, emerging evidence, practice: a report of the world health organization, department of mental health and substance abuse in collaboration with the victorian health promotion foundation and the university of melbourne
.
World Health Organization
;
2005
.
77.
VandenBos
GR
, editor,
APA dictionary of psychology
.
American Psychological Association
;
2007
.
78.
Keyes
CLM
,
Lopez
SJ
.
Toward a science of mental health: positive directions in diagnosis and interventions
. In:
Snyder
CR
,
Lopez
SJ
, editors.
Handbook of positive psychology
.
Oxford University Press
;
2002
. p.
45
59
.
79.
Wong
PTP
.
Positive psychology 2.0: towards a balanced interactive model of the good life
.
Can Psychol/Psychol Canad
.
2011
;
52
(
2
):
69
81
.
80.
Keyes
CLM
.
Complete mental health: an agenda for the 21st century
. In:
Keyes
CLM
,
Haidt
J
, editors.
Flourishing: positive psychology and the life well-lived
.
American Psychological Association
;
2003
. p.
293
312
.
81.
Keyes
CL
.
Mental illness and/or mental health? Investigating axioms of the complete state model of health
.
J Consult Clin Psychol
.
2005
;
73
(
3
):
539
48
.
82.
Greenspoon
PJ
,
Saklofske
DH
.
Toward an integration of subjective well-being and psychopathology
.
Soc indicators Res
.
2001
;
54
(
1
):
81
108
.
83.
Suldo
SM
,
Shaffer
EJ
.
Looking beyond psychopathology: the dual-factor model of mental health in youth
.
Sch Psychol Rev
.
2008
;
37
(
1
):
52
68
.
84.
Westerhof
GJ
,
Keyes
CL
.
Mental illness and mental health: the two continua model across the lifespan
.
J Adult Dev
.
2010
;
17
(
2
):
110
9
.
85.
Swogger
MT
,
Hart
E
,
Erowid
F
,
Erowid
E
,
Trabold
N
,
Yee
K
, et al
.
Experiences of kratom users: a qualitative analysis
.
J Psychoactive Drugs
.
2015
;
47
(
5
):
360
7
.
86.
Swogger
MT
,
Walsh
Z
.
Kratom use and mental health: a systematic review
.
Drug Alcohol Depend
.
2018
;
183
:
134
40
.
87.
Phoong
SW
,
Phoong
SY
,
Yeoh
YJ
.
Kratom: a bibliometric analysis of scientific publications
.
J Psychoactive Drugs
.
2024
;
56
(
1
):
14
22
.
88.
Adzrago
D
,
Obekpa
EO
,
Suragh
TA
,
John
ER
,
Yeh
PG
,
Gallardo
KR
, et al
.
Kratom use categories and their associations with co-occurring substance use and mental health disorder symptoms during the COVID-19 pandemic
.
Drug Alcohol Depend
.
2022
;
239
:
109605
.
89.
Palamar
JJ
.
Past-year kratom use in the U.S.: estimates from a nationally representative sample
.
Am J Prev Med
.
2021
;
61
(
2
):
240
5
.
90.
Parent
MC
,
Woznicki
NW
,
Yang
J
.
Demographic and behavioral factors associated with kratom use among U.S. college students
.
J Am Coll Health
.
2022
;
1–5
:
1
5
.
91.
Smith
KE
,
Dunn
KE
,
Rogers
JM
,
Garcia-Romeu
A
,
Strickland
JC
,
Epstein
DH
.
Assessment of kratom use disorder and withdrawal among an online convenience sample of US adults
.
J Addict Med
.
2022c
;
16
(
6
):
666
70
.
92.
Xu
KY
,
Mintz
CM
,
Borodovsky
JT
,
Glaser
PEA
,
Bierut
LJ
,
Grucza
RA
.
Prevalence of kratom use and Co-occurring substance use disorders in the United States
.
Prim Care Companion CNS Disord
.
2021
;
23
(
4
):
21br02930
.
93.
Rogers
JM
,
Smith
KE
,
Strickland
JC
,
Epstein
DH
.
Kratom use in the US: both a regional phenomenon and a white middle-class phenomenon? Evidence from NSDUH 2019 and an online convenience sample
.
Front Pharmacol
.
2021
;
12
:
789075
.
94.
Singh
D
,
Abdullah
MF
,
Vicknasingam
BK
,
Müller
CP
.
Substance use disorder related to kratom (Mitragyna speciosa) use in Malaysia
.
Curr Psychopharmacol
.
2019
;
8
(
1
):
64
71
.
95.
Cheung
MW
,
Vijayakumar
R
.
A guide to conducting a meta-analysis
.
Neuropsychol Rev
.
2016
;
26
(
2
):
121
8
.
96.
Page
MJ
,
McKenzie
JE
,
Bossuyt
PM
,
Boutron
I
,
Hoffmann
TC
,
Mulrow
CD
, et al
.
The PRISMA 2020 statement: an updated guideline for reporting systematic reviews
.
BMJ
.
2021
;
372
:
n71
.
97.
Fusar-Poli
P
,
Salazar de Pablo
G
,
De Micheli
A
,
Nieman
DH
,
Correll
CU
,
Kessing
LV
, et al
.
What is good mental health? A scoping review
.
Eur Neuropsychopharmacol
.
2020
;
31
:
33
46
.
98.
Swogger
MT
,
Smith
KE
,
Garcia-Romeu
A
,
Grundmann
O
,
Veltri
CA
,
Henningfield
JE
, et al
.
Understanding kratom use: a guide for healthcare providers
.
Front Pharmacol
.
2022
;
13
:
801855
.
99.
World Health Organization
.
International classification of diseases for mortality and morbidity statistics (11th Revision)
.
2018
. Available from: https://icd.who.int/browse11/l-m/en
100.
Tacconelli
E
.
Systematic reviews: CRD’s guidance for undertaking reviews in health care
.
Lancet Infect Dis
.
2010
;
10
(
4
):
226
.
101.
Methley
AM
,
Campbell
S
,
Chew-Graham
C
,
McNally
R
,
Cheraghi-Sohi
S
.
PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews
.
BMC Health Serv Res
.
2014
;
14
:
579
.
102.
Lipsey
MW
,
Wilson
DB
.
Practical meta-analysis
.
Sage Publications, Inc
;
2001
.
103.
Santrock
JW
.
Life-span development
.
New York, NY
:
McGrawHill
;
2008
.
104.
Assink
M
,
Wibbelink
CJ
.
Fitting three-level meta-analytic models in R: a step-by-step tutorial
.
Quant Method Psychol
.
2016
;
12
(
3
):
154
74
.
105.
Cheung
MW
.
Modeling dependent effect sizes with three-level meta-analyses: a structural equation modeling approach
.
Psychol Methods
.
2014
;
19
(
2
):
211
29
.
106.
National Institutes of Health
.
Quality assessment tool for observational cohort and cross-sectional studies
.
2021
. Available from: https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools
107.
National Institutes of Health
.
Quality assessment tool for controlled intervention studies
.
2021
. Available from: https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools
108.
Cohen
J
.
A coefficient of agreement for nominal scales
.
Educ Psychol Meas
.
1960
;
20
(
1
):
37
46
.
109.
Rothstein
HR
,
Sutton
AJ
,
Borenstein
M
.
Publication bias in meta-analysis: prevention, assessment and adjustments
.
John Wiley & Son Ltd
;
2005
.
110.
Sutton
AJ
,
Duval
SJ
,
Tweedie
RL
,
Abrams
KR
,
Jones
DR
.
Empirical assessment of effect of publication bias on meta-analyses
.
BMJ
.
2000
;
320
(
7249
):
1574
7
.
111.
Peters
JL
,
Sutton
AJ
,
Jones
DR
,
Abrams
KR
,
Rushton
L
.
Contour-enhanced meta-analysis funnel plots help distinguish publication bias from other causes of asymmetry
.
J Clin Epidemiol
.
2008
;
61
(
10
):
991
6
.
112.
Simmonds
M
.
Quantifying the risk of error when interpreting funnel plots
.
Syst Rev
.
2015
;
4
:
24
.
113.
Egger
M
,
Davey Smith
G
,
Schneider
M
,
Minder
C
.
Bias in meta-analysis detected by a simple, graphical test
.
BMJ
.
1997
;
315
(
7109
):
629
34
.
114.
Rosenthal
R
.
The file drawer problem and tolerance for null results
.
Psychol Bull
.
1979
;
86
(
3
):
638
41
.
115.
Duval
S
,
Tweedie
R
.
Trim and fill: a simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis
.
Biometrics
.
2000
;
56
(
2
):
455
63
.
116.
Shi
L
,
Lin
L
.
The trim-and-fill method for publication bias: practical guidelines and recommendations based on a large database of meta-analyses
.
Medicine
.
2019
;
98
(
23
):
e15987
.
117.
Lenhard
W
,
Lenhard
A
.
Computation of effect sizes
.
Psychometrica
.
2016
. Available from: https://www.psychometrica.de/effect_size.html
118.
Rosenthal
R
,
Rubin
DB
.
r equivalent: a simple effect size indicator
.
Psychol Methods
.
2003
;
8
(
4
):
492
6
.
119.
Borenstein
M
,
Hedges
LV
,
Higgins
JP
,
Rothstein
HR
.
Introduction to meta-analysis
.
Wiley
;
2011
.
120.
Shadish
WR
,
Haddock
CK
.
Combining estimates of effect size
. In:
Cooper
H
,
Hedges
LV
,
Valentine
JC
, editors.
The handbook of research synthesis and meta-analysis
.
Russell Sage Foundation
;
2009
. p.
257
77
.
121.
Viechtbauer
W
.
Conducting meta-analyses in R with the metafor package
.
J Stat Softw
.
2010
;
36
(
3
):
1
48
.
122.
Krueger
RF
,
Markon
KE
.
Reinterpreting comorbidity: a model-based approach to understanding and classifying psychopathology
.
Annu Rev Clin Psychol
.
2006
;
2
:
111
33
.
123.
Cohen
J
.
A power primer
.
Psychol Bull
.
1992
;
112
(
1
):
155
9
.
124.
Falise
AM
,
Hoeflich
CC
,
Nutley
SK
,
Lopez-Quintero
C
,
Striley
CW
.
Polysubstance use profiles among US adults using Kratom (Mitragyna speciosa): a latent class analysis using the National Survey on Drug Use and Health (NSDUH)
.
Am J Addict
.
2023
;
32
(
1
):
76
80
.
125.
Lee
J
,
Terashima
JP
,
Parker
MA
.
The association between E-cigarette use and Kratom use among US adults
.
Prev Med
.
2022
;
164
:
107295
.
126.
Nacca
N
,
Schult
RF
,
Li
L
,
Spink
DC
,
Ginsberg
G
,
Navarette
K
, et al
.
Kratom adulterated with phenylethylamine and associated intracerebral hemorrhage: linking toxicologists and public health officials to identify dangerous adulterants
.
J Med Toxicol
.
2020
;
16
(
1
):
71
4
.
127.
Lydecker
AG
,
Sharma
A
,
McCurdy
CR
,
Avery
BA
,
Babu
KM
,
Boyer
EW
.
Suspected adulteration of commercial kratom products with 7-hydroxymitragynine
.
J Med Toxicol
.
2016
;
12
(
4
):
341
9
.
128.
LeSaint
KT
,
Yin
S
,
Sharma
A
,
Avery
BA
,
McCurdy
CR
,
Waksman
JC
.
Acute renal insufficiency associated with consumption of hydrocodone- and morphine-adulterated kratom (mitragyna speciosa)
.
J Emerg Med
.
2022
;
63
(
1
):
e28
e30
.
129.
Covvey
JR
,
Vogel
SM
,
Peckham
AM
,
Evoy
KE
.
Prevalence and characteristics of self-reported kratom use in a representative US general population sample
.
J Addict Dis
.
2020
;
38
(
4
):
506
13
.
130.
Elin Smith
K
.
Prevalence and correlates of electronic cigarette use among a clinical sample of polysubstance users in Kentucky: long live the cigarette
.
Subst Use Misuse
.
2019
;
54
(
2
):
225
35
.
131.
Likhitsathian
S
,
Jiraporncharoen
W
,
Aramrattana
A
,
Angkurawaranon
C
,
Srisurapanont
M
,
Thaikla
K
, et al
.
Polydrug use among kratom users: findings from the 2011 Thailand national household survey
.
J Subst Use
.
2018
;
23
(
4
):
384
9
.
132.
Pichainarong
N
,
Chaveepojnkamjorn
W
,
Khobjit
P
,
Veerachai
V
,
Sujirarat
D
.
Energy drinks consumption in male construction workers, Chonburi province
.
J Med Assoc Thai
.
2004
;
87
(
12
):
1454
8
.
133.
Schimmel
J
,
Amioka
E
,
Rockhill
K
,
Haynes
CM
,
Black
JC
,
Dart
RC
, et al
.
Prevalence and description of Kratom (Mitragyna speciosa) use in the United States: a cross-sectional study
.
Addiction
.
2021
;
116
(
1
):
176
81
.
134.
Sharma
V
,
Cottler
LB
,
Bares
CB
,
Lopez-Quintero
C
.
Kratom use among U.S. Adolescents: analyses of the 2019 national survey on drug use and health
.
J Adolesc Health
.
2022
;
70
(
4
):
677
81
.
135.
Singh
D
,
Narayanan
S
,
Grundmann
O
,
Boyer
EW
,
Vicknasingam
B
.
The use of benzodiazepines among kratom (mitragyna speciosa korth.) users
.
J Psychoactive Drugs
.
2020f
;
52
(
1
):
86
92
.
136.
Smith
KE
,
Lawson
T
.
Prevalence and motivations for kratom use in a sample of substance users enrolled in a residential treatment program
.
Drug Alcohol Depend
.
2017
;
180
:
340
8
.
137.
Smith
KE
,
Bunting
AM
,
Walker
R
,
Hall
MT
,
Grundmann
O
,
Castillo
O
.
Non-prescribed buprenorphine use mediates the relationship between heroin use and kratom use among a sample of polysubstance users
.
J Psychoactive Drugs
.
2019
;
51
(
4
):
311
22
.
138.
Smith
KE
,
Tillson
MD
,
Staton
M
,
Winston
EM
.
Characterization of diverted buprenorphine use among adults entering corrections-based drug treatment in Kentucky
.
Drug Alcohol Depend
.
2020
;
208
:
107837
.
139.
Smith
KE
,
Dunn
KE
,
Rogers
JM
,
Grundmann
O
,
McCurdy
CR
,
Garcia-Romeu
A
, et al
.
Kratom use as more than a “self-treatment”
.
Am J Drug Alcohol Abuse
.
2022d
;
48
(
6
):
684
94
.
140.
Saref
A
,
Suraya
S
,
Singh
D
,
Grundmann
O
,
Narayanan
S
,
Swogger
MT
, et al
.
Self-report data on regular consumption of illicit drugs and HIV risk behaviors after kratom (mitragyna speciosa korth.) initiation among illicit drug users in Malaysia
.
J Psychoactive Drugs
.
2020
;
52
(
2
):
138
44
.
141.
Smith
KE
,
Feldman
JD
,
Dunn
KE
,
McCurdy
CR
,
Weiss
ST
,
Grundmann
O
, et al
.
Examining the paradoxical effects of kratom: a narrative inquiry
.
Front Pharmacol
.
2023
;
14
:
1174139
.
142.
Koob
GF
.
Anhedonia, hyperkatifeia, and negative reinforcement in substance use disorders
.
Curr Top Behav Neurosci
.
2022
;
58
:
147
65
.
143.
Chongrattanakon
N
,
Thepthien
BO
,
Hong
SA
.
Prevalence and psycho-social determinants of Kratom (Mitragyna speciosa) juice cocktail consumption among youth in Surat Thani Province, Thailand
.
J Subst Use
.
2018
;
23
(
2
):
144
53
.
144.
Yusoff
NHM
,
Suhaimi
FW
,
Vadivelu
RK
,
Hassan
Z
,
Rümler
A
,
Rotter
A
, et al
.
Abuse potential and adverse cognitive effects of mitragynine (Kratom)
.
Addict Biol
.
2016
;
21
(
1
):
98
110
.
145.
Henningfield
JE
,
Grundmann
O
,
Babin
JK
,
Fant
RV
,
Wang
DW
,
Cone
EJ
.
Risk of death associated with kratom use compared to opioids
.
Prev Med
.
2019
;
128
:
105851
.
146.
Gobbi
G
,
Atkin
T
,
Zytynski
T
,
Wang
S
,
Askari
S
,
Boruff
J
, et al
.
Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood: a systematic review and meta-analysis
.
JAMA psychiatry
.
2019
;
76
(
4
):
426
34
.
147.
McKetin
R
,
Leung
J
,
Stockings
E
,
Huo
Y
,
Foulds
J
,
Lappin
JM
, et al
.
Mental health outcomes associated with of the use of amphetamines: a systematic review and meta-analysis
.
EClinicalMedicine
.
2019
;
16
:
81
97
.
148.
Koechl
B
,
Unger
A
,
Fischer
G
.
Age-related aspects of addiction
.
Gerontology
.
2012
;
58
(
6
):
540
4
.
149.
Richmond-Rakerd
LS
,
Slutske
WS
,
Lynskey
MT
,
Agrawal
A
,
Madden
PAF
,
Bucholz
KK
, et al
.
Age at first use and later substance use disorder: shared genetic and environmental pathways for nicotine, alcohol, and cannabis
.
J Abnorm Psychol
.
2016
;
125
(
7
):
946
59
.
150.
Peterson
RA
,
Brown
SP
.
On the use of beta coefficients in meta-analysis
.
J Appl Psychol
.
2005
;
90
(
1
):
175
81
.
151.
Müller
CP
.
Drug instrumentalization
.
Behav Brain Res
.
2020
;
390
:
112672
.
You do not currently have access to this content.