VEGAS as a Platform for Facile Directed Evolution in Mammalian Cells.

Directed evolution, artificial selection toward designed objectives, is routinely used to develop new molecular tools and therapeutics. Successful directed molecular evolution campaigns repeatedly test diverse sequences with a designed selective pressure. Unicellular organisms and their viral pathogens are exceptional for this purpose and have been used for decades. However, many desirable targets of directed evolution perform poorly or unnaturally in unicellular backgrounds. Here, we present a system for facile directed evolution in mammalian cells. Using the RNA alphavirus Sindbis as a vector for heredity and diversity, we achieved 24-h selection cycles surpassing 10-3 mutations per base. Selection is achieved through genetically actuated sequences internal to the host cell, thus the system's name: viral evolution of genetically actuating sequences, or "VEGAS." Using VEGAS, we evolve transcription factors, GPCRs, and allosteric nanobodies toward functional signaling endpoints each in less than 1 weeks' time.

Kratom (Mitragyna speciosa) Use and Mental Health: A Systematic Review and Multilevel Meta-Analysis.

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 (ß1 = -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.

[Kratom-From natural remedy to addictive drug and back]. / Kratom ­ vom natürlichen Heilmittel zur Suchtdroge und zurück.

BACKGROUND: Kratom/ketum is a psychoactive herbal preparation that has been used for a long time as a remedy and performance-enhancing substance in Southeast Asia. The advancement of globalization is making kratom increasingly more available in the western world, where it is becoming increasingly more used. OBJECTIVE: The current research on kratom and its ingredients is presented. MATERIAL AND METHODS: An overview of the use and effects of kratom is exemplary given on the basis of reports. The instrumentalization of the drug and its consequences up to the development of addiction are discussed. RESULTS: Consumption is accompanied by several instrumentalizeable effects so that kratom is used as a therapeutic substance in the self-management of pain, anxiety and depression as well as other substance addictions. Another benefit comes from the performance-enhancing effects on physical work and in a social context. Consumption is usually well controlled, rarely escalates and has few and mostly mild aversive side effects. The danger arises from consumption particularly when there is an escalation of the dose and from mixed consumption with other psychoactive substances. The main alkaloid mitragynine and the more potent 7­hydroxy-mitragynine are considered mainly responsible for the effect. Both have a complex pharmacology that involves partial µ­opioid receptor agonism. DISCUSSION: Epidemiological, clinical and neurochemical studies have shown that kratom only has a limited addictive drug profile, which might suggest a medical use as a remedy or substitute in addiction treatment.

Development and validation of ELISA for screening of Kratom (Mitragyna speciosa) habitual users using urinary AZ122 biomarker.

Kratom (Mitragyna speciosa Korth) has been used traditionally in Southeast Asia for its therapeutic properties. The major alkaloid of kratom, mitragynine, binds to opioid receptors to give opioid-like effects that causes addiction. In our previous study, we have identified AZ122 as a unique biomarker in habitual or regular kratom users through analysis of their urinary protein profiles. We aimed to develop and validate a screening method by means of enzyme-linked immunosorbent assay (ELISA) for detection of kratom habitual users. An ELISA approach was applied for the development of a screening method using urinary AZ122 as biomarker. Method validation was carried out using three quality control materials at different concentration of AZ122. The data was analyzed statistically using SPSS (Version 25). The ELISA was presented with Pearson correlation coefficient of 0.9993. The repeatability and reproducibility were presented at CV <7%, while the accuracy ranged from 78 to 96% at various AZ112 concentrations. Upon testing on 176 male respondents (n = 88 regular kratom users and n = 88 healthy controls), the specificity and sensitivity of the assay were both 100%. The ELISA has been validated and can be potentially used as a reliable screening test for detection of kratom habitual users.

Evaluation of toxicity profile of kratom (Mitragyna speciosa Korth) decoction in rats.

Mitragyna speciosa Korth also known as kratom, is an herbal drug preparation for its therapeutic properties and opioid-replacement therapy. Kratom is consumed in a brewed decoction form in Malaysia and to date, no studies have characterized its chemical and toxicity profile. Thus, this study aims to evaluate kratom decoction's safety and toxicity profile after 28 days of treatment. Mitragynine content was quantified in kratom decoction and used as a marker to determine the concentration. Male and female Sprague Dawley rats were orally treated with vehicle or kratom decoction (10, 50 or 150 mg/kg) and two satellite groups were treated with vehicle and kratom decoction (150 mg/kg). Blood and organs were collected for hematology, biochemical and histopathology analysis at the end of treatment. No mortality was found after 28 days of treatment and no significant changes in body weight and hematology profile, except for low platelet count. High amounts of uric acid, AST, ALT and alkaline phosphatase were found in the biochemical analysis. Histological investigation of the heart and lungs detected no alterations except for the kidney, liver and brain tissues. In conclusion, repeated administration of kratom decoction provided some evidence of toxicity in the kidney and liver with no occurrence of mortality.

The Health Impact of Long-Term Kratom (Mitragyna Speciosa) Use in Southern Thailand.

BACKGROUND: Mitragyna speciosa or Kratom has been used in Thailand traditionally for its medicinal value. Despite case reports of kratom consumption causing adverse effects, research on its long-term health impact is limited. This study examines the long-term health impact of kratom use among people in Southern Thailand. METHODS: Three community-based surveys were conducted from 2011 to 2015. In the first and second surveys (2011 and 2012) a total of 1,118 male respondents comprising 355 regular kratom users, 171 occasional kratom users, 66 ex-users, and 592 non-users aged 25 or above, were recruited from 40 villages. All respondents were followed up in this study. However, not all respondents were successfully followed up throughout the entire set of studies. RESULTS: Common health complaints were no more common among kratom users than ex- and non-users, but more regular than occasional users claimed kratom to be addictive. Those with high kratom dependence scores were more likely to experience intense withdrawal symptoms, which developed 1-12 h after the last kratom intake. Over half (57.9%) of regular users had experienced intoxication effects compared to only 29.3% of occasional users. Kratom users were less likely to have a history of chronic diseases such as diabetes, hypertension, dyslipidemia than ex- and non-users. CONCLUSION: Regular long-term chewing of fresh kratom leaves was not related to an increase in common health complaints, but may pose a drug dependence risk. Severe kratom dependents were more likely to suffer from intense withdrawal symptoms. Medical records revealed no death due to traditional kratom use, but the high prevalence of tobacco or/and hand rolled cigarette smoking among kratom users should be of concern.

Kratom (Mitragyna speciosa) use in a sample of drug-dependent adolescents in rehabilitation for drug use in Malaysia.

BACKGROUND: Leaves derived from the Kratom (Mitragyna speciosa) tree have been traditionally ingested for their curative properties by diverse groups of the population including people who use drugs (PWUDs) in Southeast Asia. This study investigated the motives for using kratom among drug-dependent adolescents. METHODS: Eighty adolescents who were undergoing mandatory drug rehabilitation volunteered to participate in this mixed-method, cross-sectional study. All respondents answered a semi-structured questionnaire while a few were interviewed in-depth. RESULTS: The majority were males (70%, n = 56/80). The respondents' mean age at admission was 18.2 years (SD = 1.40), and 65% were between 14 and 18 years old. Sixty-three percent (n = 50/80) had used crystal methamphetamine alone, while the rest had co-used crystal methamphetamine with heroin. About three-fifths (60%, n = 48/80) had a history of kratom use. Kratom was commonly used for many perceived benefits such as increasing energy, reducing crystal methamphetamine intake, intensifying euphoria, easing heroin withdrawal, as a heroin substitute and reducing heroin use. In addition, the multivariate analysis indicated that higher odds of kratom use were associated with those who were employed, used only crystal methamphetamine, were recent drug users, and had no prior incarceration history. CONCLUSION: While kratom was being used for its multifold perceived benefits, it also functions as a means to self-treat withdrawal from illicit drug use among drug-dependent adolescents.

Factors associated with drug use during pregnancy and breastfeeding among females who use drugs (FWUDs) in Malaysia.

Females who use drugs (FWUDs) are at risk of continuing illicit substance use during pregnancy and breastfeeding. We investigated the prevalence rates and factors associated with these practices in a sample of 200 FWUDs recruited from a publicly-run drug rehabilitation center. A semi-structured questionnaire was used to collect the data. The majority (86%) was Malay (n = 171/200), currently single (71%, n = 141/200), and 51% had nine years of education. The mean age of respondents was 32.2 years (SD = 8.61). Thirty-eight percent (n = 75/200) reported ever using illicit substances during pregnancy, while 15% (n = 30/200) had used them during breastfeeding. Higher odds of using drugs during pregnancy were associated with having an intimate male drug-using partner and with persons who reported abandoning an infant in the past. Lower odds were linked with women who used heroin with ATS (relative to those who used only ATS), and shorter-term ATS (≤3 years) relative to long term ATS users. At a lower level of significance (p = 0.054), being married also lowered the odds. Higher odds of drug use during breastfeeding were associated with having an intimate male drug-using partner, and previous methadone use history, while lower odds were associated with short-term ATS use and being employed. The findings highlight the need for timely and targeted interventions to inform, engage and promote the participation of FWUDs in pre- and post-natal care services.

Exploring the self-reported motivations of kratom (Mitragyna speciosa Korth.) use: a cross-sectional investigation.

Background: Kratom (Mitragyna speciosa Korth.) use outside of Southeast Asia has increased over the past decade. Objectives: This investigation clarifies kratom's role in perceived well-being, overall health, and temporal correlation with drug use to understand kratom's role in the self-treatment of substance use disorders (SUDs). Methods: Between July 2019 and July 2020 an anonymous, cross-sectional, online survey was taken by 7,381 people who use kratom (PWUK) recruited through social media and other online resources. This included an assessment of (a) the relationship between self-reported overall health, concomitant use of drugs of misuse, and demographics; (b) the perceived effectiveness of kratom in self-treating diagnosed health conditions or symptoms; (c) the profile of PWUK primarily for drug dependence, pain, and mood or mental health conditions based on demographics. Results: A total of 5,152 valid responses (45.9% females/53.7% males) were collected. Kratom was primarily used for self-treating pain (73.0%) and improving emotional or mental health conditions (42.2%) without clinical supervision. Those with a SUD (synthetic opioids, methadone, benzodiazepines, or heroin) used kratom after discontinuing illicit or other drugs (94.8%). The primary substances taken before or concomitantly with kratom were cannabis, cannabidiol, benzodiazepines, or kava. PWUKs report a dose-dependent benefit for alleviating pain and relieving negative moods. Adverse effects were primarily gastrointestinal, typically at high (>5 g/dose) and frequent (>22 doses/week) dosing. Conclusions: Kratom was primarily used as a harm-reduction agent for SUDs and self-treatment of chronic conditions. Healthcare professionals need better information about kratom, its potential adverse effects, and clinically significant drug interactions.

Need for clarity and context in case reports on kratom use, assessment, and intervention.

This Letter to the Editor is a response to Broyan and colleagues who recently published a Case Report presenting data on 28 patients in the United States who identified kratom as their primary substance of use and who were subsequently induced on buprenorphine/naloxone for a reported diagnosis of kratom use disorder. We applaud the authors for helping to advance the science on kratom and recognize the difficulties in conducting kratom-related clinical assessment and research. However, a number of inconsistences and generalizations were identified in this Case Report, which also lacked some critical context. Importantly, such inconsistencies and generalizations can be observed throughout kratom-specific case reports. We feel this is now an important opportunity to highlight these issues that are present in the Broyan and colleagues Case report but emphasize that they are not unique to it. We do this with the hope that by acknowledging these issues it can help inform editors, clinicians, and researchers who may not be familiar with kratom and, as a result of this unfamiliarity, may inadvertently present findings in a manner that could confuse readers and even misinform clinical researchers and practitioners.

Barriers to enrolling in voluntary treatment programs in Malaysia: a study of women who use methamphetamine (WWUM).

Women with substance use disorders (SUDs) have been widely reported to face barriers in seeking treatment. We sought to identify barriers that prevented women who use methamphetamine (WWUM) from accessing the decade-old Voluntary Treatment Centers (VTCs) in Malaysia. A total of 153 WWUM who were undergoing rehabilitation for methamphetamine use at a compulsory drug detention center (CDDC) were recruited for this cross-sectional study. Data were collected by canvasing a structured questionnaire through face-to-face meetings. Of the total sample, 131 (86%) were Malays, with a mean age of 32.1 years. The commonly cited treatment barriers were the belief that methamphetamine use was not problematic (42%), not knowing how to seek treatment (38%), feeling embarrassed to seek treatment (33%), the lack of family support (24%), and the long waiting time for enrollment (23%). Logistic analyses indicated that a longer duration of use increased the odds of not acknowledging methamphetamine use as a problem while older participants had lower odds of holding a similar view. A longer duration of use also increased the odds of claiming treatment was not needed but lowered the odds of asserting a lack of confidence in treatment. Furthermore, Malays had higher odds of lacking family support in seeking treatment while being employed lowered the odds of not wanting treatment. Addressing these concerns will hopefully encourage higher participation of WWUM in voluntary treatment programs.

Exploring the Chemistry of Alkaloids from Malaysian Mitragyna speciosa (Kratom) and the Role of Oxindoles on Human Opioid Receptors.

Ten indole and oxindole alkaloids (1-10) were isolated from the freshly collected leaves of Malaysian Mitragyna speciosa (Kratom). The chemical structures of these compounds were established on the basis of extensive 1D and 2D NMR and HRMS data analysis. The spectroscopic data of mitragynine oxindole B (4) are reported herein for the first time. The spatial configuration of mitragynine oxindole B (4) was confirmed by single-crystal X-ray diffraction. Simultaneous quantification of the isolated alkaloids in the M. speciosa leaf specimens collected from different locations in the northern region of Peninsular Malaysia was also performed using UPLC-MS/MS. The oxindole alkaloids (1-4) and the indole alkaloid (10) were assessed for binding affinity at opioid receptors. Corynoxine (1) showed high binding affinity to µ-opioid receptors with a Ki value of 16.4 nM. Further, corynoxine (1) was 1.8-fold more potent than morphine in rats subjected to a nociceptive hot plate assay. These findings have important implications for evaluating the combined effects of the minor oxindole alkaloids in the overall therapeutic activity of M. speciosa.

Factors affecting addiction severity index (ASI) among clients enrolled in methadone maintenance treatment (MMT) program in Myanmar.

BACKGROUND: Opioid substitution with methadone maintenance treatment (MMT) is shown to reduce illicit opioid use and renew social functioning. Understanding factors that undermine clients' social functioning during MMT treatment is vital for improving treatment compliance and quality of life. METHOD: A total of 210 respondents who were already enrolled in a formal MMT program in Myanmar were recruited from five cities through stratified random sampling for this cross-sectional study. The addiction severity index (ASI) was used to objectively assess respondents social functioning in the last 30 days. Higher ASI scores denote poorer social functioning. RESULT: Respondents total ASI scores in the respective domains were: employment (47.4%), alcohol (44.4%), drug use (7.2%), legal (49.2%) and social-family relationship (10.7%). Those reported to have never injected drugs in the last 30 days had lower ASI total scores than those who reported injection drug use (p = 0.01). After identifying the differences in ASI total scores, we found there were significant associations in the clients' hepatitis C status, age category, frequency of heroin injection, quality of life score, marital status, current leisure status with family/friend, current history of injection in the last 30 days, income status, satisfaction with current marital status, as well as reported drug and alcohol use (p < 0.05). Stepwise binary logistic regression showed that alcohol and higher frequency of heroin injection were associated with higher ASI scores. Meanwhile, older age, respondents those who had leisure time with family, and satisfied with current marital status had lower ASI scores (p < 0.05). CONCLUSION: Our results indicate that those enrolled in the MMT program in Myanmar faced many challenges in their daily social functioning. Treatment providers must take heed of these apparent impediment to ensure clients chequered social functioning does not undermine their treatment compliance. TRIAL REGISTRATION: NA.

Effect of regular kratom (Mitragyna speciosa Korth.) use on quality of life of people who use kratom.

Background: Kratom (Mitragyna speciosa Korth.) is a traditional folk remedy used in Southeast Asia and is known to have a significant opioid-like effect. However, it is unknown whether kratom consumption can impair quality of life (QoL). This study aimed to examine the QoL of people who use kratom by comparing it with that of healthy non-kratom using controls and to determine the association between patterns of kratom use and QoL among people who use kratom. Methods: 200 respondents (100 subjects who use kratom and 100 healthy controls) were recruited for this cross-sectional study. The World Health Organization Quality of Life-BREF was administered to all the respondents to assess QoL, while the Kratom Dependence Scale (KDS) was used to assess the severity of kratom dependence among the subjects who use kratom. Results: The physical health, psychological, and environment QoL scores of the subjects who use kratom were significantly lower than those of the healthy controls. Multiple linear regression analysis revealed greater KDS score and longer duration of kratom use were significant predictors of physical health QoL, while only greater KDS score significantly predicted psychological and environment QoL scores. Conclusion: Prolonged kratom use and kratom dependence may negatively impact the QoL of people who use kratom, hence kratom addiction has to be treated adequately.

Kratom and Pain Tolerance: A Randomized, Placebo-Controlled, Double-Blind Study.

Background: Kratom has a long history of traditional medicine use in Southeast Asia. Consumption of kratom products has also been reported in the US and other regions of the world. Pain relief is among many self-reported kratom effects but have not been evaluated in controlled human subject research. Methods: Kratom effects on pain tolerance were assessed in a randomized, placebo-controlled, double-blind study. During a 1-day inpatient stay, participants received a randomized sequence of kratom and placebo decoctions matched for taste and appearance. Pain tolerance was measured objectively in a cold pressor task (CPT) as time (seconds) between the pain onset and the hand withdrawal from the ice bath. Health status, vital signs, objective, and subjective indicators of withdrawal symptoms, self-reported data on lifetime kratom use patterns, and assessments of blinding procedures were also evaluated. Results: Twenty-six males with the mean (SD) age 24.3 (3.4) years were enrolled. They reported the mean (SD) 6.1 (3.2) years of daily kratom consumption. Pain tolerance increased significantly 1 hour after kratom ingestion from the mean (SD) 11.2 (6.7) seconds immediately before to 24.9 (39.4) seconds 1 hour after kratom consumption (F(2,53.7)=4.33, p=0.02). Pain tolerance was unchanged after consuming placebo drinks: 15.0 (19.0) seconds immediately before and 12.0 (8.1) seconds 1 hour after consumption of placebo (F(2,52.8)=0.93, p=0.40). No discomfort or signs of withdrawal were reported or observed during 10-20 hours of kratom discontinuation. Conclusions: Kratom decoction demonstrated a substantial and statistically significant increase in pain tolerance. Further rigorous research on kratom pain-relieving properties and a safety profile is needed.

Effects of kratom (Mitragyna speciosa Korth.) in reducing risk-behaviors among a small sample of HIV positive opiate users in Malaysia.

Out-of-treatment HIV positive opiate users often engage in risky injecting and sexual behaviors. We sought the self-reported experiences on whether or not kratom (Mitragyna speciosa Korth.) use was associated with a reduction in HIV risk behaviors among them. A convenience sample consisting of thirty-two HIV positive opiate users participated in the study. Of this, three-fifths (n = 20/32) used kratom to suppress opiate withdrawal, increase energy, as a heroin substitute, to reduce heroin dependence and self-treat psychological problems. More than one-third (38%) in the sample claimed that kratom use reduced their risky injecting and sexual behaviors. Given the small sample size, the perceived association between kratom use and the reduction in HIV risk behaviors could not be established more convincingly. However, the findings provide the basis for a broader-based study to evaluate the potential of kratom in curtailing HIV risk behaviors among HIV positive opiate users.

Effects of Kratom (Mitragyna Speciosa Korth.) Use in Regular Users.

Background: Mitragyna speciosa (Korth.) or kratom is an indigenous medicinal plant of Southeast Asia. Kratom is widely reported to have dose-dependent effects based on available literature, but to our knowledge, this has not been established conclusively. Objective: This study sought to evaluate if kratom use produces dose-dependent effects, with a stimulant effect at low doses and a sedative effect at high doses, in a sample of regular kratom users. Methods: A total of 63 regular kratom users participated in this cross-sectional study. The Brief-Biphasic Alcohol Effects Scale (B-BAES) was used to determine subjects self-report kratom use experiences. Results: Almost all in the sample were male (98%, n = 62/63), and the majority of subjects were Malays (94%, n = 59/63). The mean age of the subjects in the sample was 43.8 years (SD = 12.1). Seventy-five percent (n = 47/63) have >5 years kratom use history, and 65% (n = 41/63) consumed >3 glasses of kratom daily. Results from first test showed no significant difference in the stimulant (t61 =0.371, p < .331) and sedative effects (t61 =502, p < .759) between those who consumed >3 glasses a day or less than this amount, regardless of duration of use. In the second test, no significant differences in the mean scores were found among those who consumed >3 glasses daily or less than this amount among short-term or long-term uses. Conclusions: Daily kratom use produced both stimulant and sedative effects but they were not statistically significantly associated with the dose consumed, both among short-term and long-term users in our sample.

Variation in chromatin accessibility in human kidney cancer links H3K36 methyltransferase loss with widespread RNA processing defects.

Comprehensive sequencing of human cancers has identified recurrent mutations in genes encoding chromatin regulatory proteins. For clear cell renal cell carcinoma (ccRCC), three of the five commonly mutated genes encode the chromatin regulators PBRM1, SETD2, and BAP1. How these mutations alter the chromatin landscape and transcriptional program in ccRCC or other cancers is not understood. Here, we identified alterations in chromatin organization and transcript profiles associated with mutations in chromatin regulators in a large cohort of primary human kidney tumors. By associating variation in chromatin organization with mutations in SETD2, which encodes the enzyme responsible for H3K36 trimethylation, we found that changes in chromatin accessibility occurred primarily within actively transcribed genes. This increase in chromatin accessibility was linked with widespread alterations in RNA processing, including intron retention and aberrant splicing, affecting ∼25% of all expressed genes. Furthermore, decreased nucleosome occupancy proximal to misspliced exons was observed in tumors lacking H3K36me3. These results directly link mutations in SETD2 to chromatin accessibility changes and RNA processing defects in cancer. Detecting the functional consequences of specific mutations in chromatin regulatory proteins in primary human samples could ultimately inform the therapeutic application of an emerging class of chromatin-targeted compounds.

Changing trends in the use of kratom (Mitragyna speciosa) in Southeast Asia.

OBJECTIVE: Kratom (Mitragyna speciosa. Korth) is an indigenous medicinal plant of Southeast Asia. This review paper aims to describe the trends of kratom use in Southeast Asia. DESIGN: A literature review search was conducted through ScienceDirect, Scopus, ProMed and Google Scholar. Twenty-five articles illustrating kratom use in humans in Southeast Asia were reviewed. RESULTS: Kratom has long been used by rural populations in Southeast Asia as a remedy for common ailments, to fight fatigue from hard manual work, as a drink during social interaction among men, and in village religious functions. Studies based on self-reports suggest that prolonged kratom use does not result in serious health risks or impair social functioning. Two recent trends have also emerged: (a) Kratom is reportedly being used to ease withdrawal from opioid dependence in rural settings; whereas (b) in urban areas, adulterated kratom cocktails are being consumed by younger people to induce euphoria. CONCLUSIONS: Legal sanctions appear to have preceded serious scientific investigations into the claimed benefits of ketum. More objective-controlled trials and experiments on humans need to be conducted to validate self-report claims by kratom users in the community.