Men Who Have Sex With Men in Peru: Acceptability of Medication-Assisted Therapy for Treating Alcohol Use Disorders

Considerations and recommendations for mHealth interventions for substance use among Sexual and Gender Minority (SGM) individuals: A narrative review of the past 5 years

Purposeof Review

The prevalence of problematic substance use is disproportionately higher among sexual and gender minority (SGM) adults compared to adults in the general population. mHealth as a treatment modality could reduce barriers to accessing substance use treatments among SGM populations. Through a qualitative literature search, the current narrative review aimed to understand the lived experiences of SGM individuals who use substances and to synthesize recommendations made in the literature to inform future mHealth interventions.

Recent Findings

Positive and negative reinforcement motives were prominent reasons for substance use, which included SGM identity expression and conformity motives. Individual- and system-level treatment barriers included a lack of safe and nonjudgmental environment, shame and stigma, and limited knowledge about treatment options. Barriers were directly linked to the reported substance use treatment needs in this population.

Summary

On-demand app features, real-time intervention and assessment, and anonymity should be considered in future mHealth trials.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40429-023-00497-0.

Patients' perspectives of medications for addiction treatment in HIV clinics: A qualitative study

BACKGROUND

While substance use disorders (SUD) disproportionately impact people with HIV (PWH), HIV clinics inconsistently provide evidence-based medications for addiction treatment (MAT). Patient receptivity to MAT is critical to enhance addiction treatment in these settings. However, we know little from patients about how to best integrate MAT into HIV clinics.

METHODS

This qualitative study used four focus groups informed by the Promoting Action on Research Implementation in Health Services framework to identify barriers and facilitators to receiving opioid, alcohol, and tobacco use disorder care in HIV clinics. The study population included 28 patients with HIV and SUD receiving care at one of four HIV clinics in the northeastern United States. Focus groups were recorded and transcribed for content analysis. The study also performed a brief survey assessing demographics and behaviors.

RESULTS

Focus groups revealed several major themes related to MAT in HIV clinics. Barriers included stigma around MAT, knowledge deficits about available MAT options and the impact of substance use on PWH, concerns about medication side effects, substance use screening without adequate clinician follow-up, and peers who discouraged MAT. Facilitators included recognition of substance use as a threat to overall health, integrated care from HIV clinicians, and support for addiction treatment from peers with lived experience.

CONCLUSIONS

Efforts to enhance MAT in HIV clinics should include patient education to help them recognize addiction as a chronic disease with available medication treatment options; clinician and staff training to promote integrated, multidisciplinary screening and treatment; and thoughtful inclusion of peers with lived experience.

HIV and Substance Use in Latin America: A Scoping Review

This scoping review aims to explore the interplay between substance use (SU) and HIV in Latin America (LA). Database searches yielded 3481 references; 196 were included. HIV prevalence among people who used substances (PWUS) ranged from 2.8–15.2%. SU definitions were variable throughout studies, and thus data were not easily comparable. In 2019, only 2% of new HIV infections were attributed to injection drug use (IDU) in LA. Factors associated with HIV among PWUS included being female, IDU and homelessness, and PWUS were likely to engage in risky sexual behaviors, start antiretroviral treatment late, have poor adherence, have treatment failure, be lost to follow-up, have comorbidities, and experience higher mortality rates and lower quality of life, as has been reported in PLWH with SU in other regions. Five intervention studies were identified, and only one was effective at reducing HIV incidence in PWUS. Interventions in other regions have varying success depending on context-specific characteristics, highlighting the need to conduct more research in the LA region. Though progress has been made in establishing SU as a major concern in people living with HIV (PLWH), much more is yet to be done to reduce the burden of HIV and SU in LA.

Exploring Contextual Differences for Sexual Role Strain Among Transgender Women and Men Who Have Sex with Men in Lima, Peru

Sexual and gender politics inform relational expectations surrounding sexual experiences of Peruvian transgender women (TW) and men who have sex with men (MSM). We used the framework of sexual role strain, or incongruence between preferred sexual role and actual sexual practices, to explore potential conflicts between personally articulated identities and externally defined norms of gender and sexuality and its potential to increase HIV/STI risk. Cross-sectional individual- and dyad-level data from 766 TW and MSM in Lima, Peru were used to assess the partnership contexts within which insertive anal intercourse was practiced despite receptive role preference (receptive role strain), and receptive anal intercourse practiced despite insertive role preference (insertive role strain). Sexual role strain for TW was more common with non-primary partners, while for MSM it occurred more frequently in the context of a primary partnership. Receptive role strain was more prevalent for TW with unknown HIV status (reference: without HIV) or pre-sex drug use (reference: no pre-sex drug use). For homosexual MSM, receptive role strain was more prevalent during condomless anal intercourse (reference: condom-protected) and with receptive or versatile partners (reference: insertive). Among heterosexual or bisexual MSM, insertive role strain was more prevalent with insertive or versatile partners (reference: receptive), and less prevalent with casual partners (reference: primary). Our findings suggest TW and MSM experience different vulnerabilities during sexual role negotiation with different partner-types. Future studies should explore the impact of sexual role strain on condom use agency, HIV/STI risk, and discordances between public and private presentations of gender and sexual orientation.

Viral Suppression Levels in Men Who Have Sex With Men and Transgender Women With Newly Diagnosed HIV and Alcohol Use Disorder in Peru: Results From a Randomized, Double-Blind, Placebo-Controlled Trial Using Oral Naltrexone

BACKGROUND

Alcohol use disorders (AUDs) are common in men who have sex with men (MSM) and transgender women (TGW) in Peru and undermine antiretroviral therapy (ART) adherence. Oral naltrexone (NTX) is an evidence-based treatment for AUD that has not been assessed in cotreating AUD in MSM/TGW with HIV.

SETTING AND DESIGN

A multi-site, randomized, double-blind, placebo-controlled trial among MSM/TGW with AUD and newly diagnosed with HIV in Lima, Peru.

METHODS

Newly diagnosed MSM/TGW with HIV and AUD were prescribed a single-treatment regimen of EFV/TDF/FTC from 2014 to 2015 and randomized 2:1 to oral NTX (N = 103) or placebo (N = 53) for 24 weeks. The primary and secondary outcomes were proportion achieving viral suppression (VS: HIV-1 RNA < 400 copies/mL) or maximal viral suppression (MVS: HIV-1 RNA < 40 copies/mL) at 24 weeks.

RESULTS

There were no significant differences between the arms in VS (81.6% NTX arm vs 75.5% placebo arm; P = 0.37) or MVS (61.2% NTX arm vs 66.0% placebo arm; P = 0.48). Adherence to study medication was low (mean = 34.6%) overall with only 21.4% of participants meeting recommended adherence levels (≥80% daily doses/month). Participants allocated to NTX had significantly lower adherence compared with placebo for both the first and second 12-week study periods, respectively (44.0% vs 35.2%, P = 0.04; 31.4% vs 35.2%, P = 0.03).

CONCLUSIONS

Findings are inconclusive regarding the use of NTX for treatment of AUD in MSM/TGW newly diagnosed with HIV. VS and MVS levels were high irrespective of allocation. Adherence to study medication was low, requiring further exploration of strategies to optimize adherence to NTX as AUD treatment.

Intimate Partner Violence Against Transgender Women: Prevalence and Correlates in Lima, Peru (2016-2018)

Limited data exists on intimate partner violence (IPV) among transgender women (TW), though global trends suggest IPV is associated with HIV risk in this population. We describe the prevalence of verbal, physical, and/or sexual violence as well as participant- and partner-level correlates of IPV among TW in Lima, Peru. Among 389 respondents, 15.2% reported IPV with one or more of their last three sexual partners: 9.2% verbal, 8.2% physical, and 2.3% sexual violence. Physical and verbal violence were more common with stable partners (aPR 3.46, 95% CI 1.17-10.25, aPR 2.46, 95% CI 1.14-5.28, respectively). Physical violence was associated with condomless receptive anal intercourse (cRAI) (aPR 2.22, 95% CI 1.19-4.13) and partner alcohol use (aPR 4.38, 95% CI 1.56-12.33) while verbal violence correlated with participant inebriation (aPR 4.86, 95% CI 1.63-14.46). Our results link IPV with stable partnerships, alcohol use, and cRAI, suggesting TW in Peru may benefit from multidimensional IPV prevention strategies to foster supportive relationships and reduce HIV transmission.

Safety of oral naltrexone in HIV-positive men who have sex with men and transgender women with alcohol use disorder and initiating antiretroviral therapy

HIV disproportionately affects men who have sex with men (MSM) and transgender women (TW). These populations use alcohol more heavily than the general population, and alcohol use disorders (AUDs) are more prevalent among them. Naltrexone (NTX) has documented efficacy and safety as a medication-assisted therapy for AUD. Its use has not been well-examined in persons with HIV (PWH) newly initiating antiretroviral therapy (ART) where the possibility of hepatotoxicity may be increased when initating multiple new medications. This study assessed the safety of oral NTX treatment (50 mg daily) initiated concomitantly with antiretroviral therapy (ART) in a double-blind randomized placebo-controlled trial of NTX in MSM/TW in Lima, Peru among MSM and TW with AUD (AUDIT score ≥ 8). We analyzed adverse event data from ART-naïve participants (N = 155) who were randomized (2:1) to initiate ART plus NTX (N = 103) or ART plus placebo (N = 52). Participants were monitored for 24 weeks while taking ART plus NTX/placebo, followed by 24 weeks receiving ART alone. Over 48 weeks, 135 grade 2 or 3 adverse events were reported, resulting in 1.3 clinical adverse events per participant equally represented in both treatment and placebo arms. Two serious adverse events occurred among two participants receiving NTX; neither was attributed to the study medication. No significant differences were found in the proportion of subjects reporting any adverse events between treatment arms across all time-points. These results suggest NTX is safe in MSM/TW PWH with AUD newly initiating ART, as no excess of clinical adverse events or transaminase elevation was associated with NTX use.

'My Tablets are on Top of the Fridge': The Roles of Relationship Desire and Medical Mistrust in ART Adherence for HIV-Positive MSM and Transgender Women Living in Rural South Africa

Given the high HIV prevalence for men who have sex with men (MSM) and transgender women in South Africa, there is limited understanding of social determinants that influence antiretroviral treatment (ART) adherence. Although universal testing and treatment (UTT) is available, ART adherence remains suboptimal. We conducted focus groups with MSM and transgender women in order to understand factors influencing their ART adherence in Mpumalanga, South Africa. All focus groups were audio-recorded, transcribed and translated for analysis using a constant comparison approach, guided by the concept of Therapeutic Citizenship. We found there is medical mistrust of ART based on differing interpretations of HIV cure that may influence treatment adherence behaviors within social networks, and relationship desire had a significant influence on optimal ART adherence. Our findings suggest that clinics must provide interventions that integrate HIV disclosure and relationship skill-building to support optimal ART adherence for MSM and transgender women under UTT.

Addressing unhealthy alcohol use among people living with HIV: recent advances and research directions

PURPOSE OF REVIEW

Unhealthy alcohol use is prevalent among people living with HIV (PLWH). We sought to identify the most current literature examining the impact of unhealthy alcohol on health outcomes and latest developments on how to best intervene.

RECENT FINDINGS

New research shows that PLWH have heightened morbidity and mortality at lower levels of alcohol consumption compared with HIV-uninfected persons. Studies published since 2016 have further elucidated the effects of persistent unhealthy alcohol use on HIV treatment outcomes over time. Screening and brief interventions, as well as pharmacologic treatment, can reduce unhealthy alcohol use among PLWH.

SUMMARY

Unhealthy alcohol use is an important and modifiable risk factor for poor health and HIV treatment outcomes among PLWH. More research is needed to encourage and maintain engagement in alcohol-related interventions and improve implementation.

Serious adverse events reported in placebo randomised controlled trials of oral naltrexone: a systematic review and meta-analysis

BACKGROUND

Naltrexone is an opioid antagonist used in many different conditions, both licensed and unlicensed. It is used at widely varying doses from 3 to 250 mg. The aim of this review was to extensively evaluate the safety of oral naltrexone by examining the risk of serious adverse events and adverse events in randomised controlled trials of naltrexone compared to placebo.

METHODS

A systematic search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, other databases and clinical trials registries was undertaken up to May 2018. Parallel placebo-controlled randomised controlled trials longer than 4 weeks published after 1 January 2001 of oral naltrexone at any dose were selected. Any condition or age group was included, excluding only studies in opioid or ex-opioid users owing to possible opioid/opioid antagonist interactions. The systematic review used the guidance of the Cochrane Handbook and Preferred Reporting Items for Systematic Reviews and Meta-analyses harms checklist throughout. Numerical data were independently extracted by two people and cross-checked. Risk of bias was assessed with the Cochrane risk-of-bias tool. Meta-analyses were performed in R using random effects models throughout.

RESULTS

Eighty-nine randomised controlled trials with 11,194 participants were found, studying alcohol use disorders (n = 38), various psychiatric disorders (n = 13), impulse control disorders (n = 9), other addictions including smoking (n = 18), obesity or eating disorders (n = 6), Crohn's disease (n = 2), fibromyalgia (n = 1) and cancers (n = 2). Twenty-six studies (4,960 participants) recorded serious adverse events occurring by arm of study. There was no evidence of increased risk of serious adverse events for naltrexone compared to placebo (risk ratio 0.84, 95% confidence interval 0.66-1.06). Sensitivity analyses pooling risk differences supported this conclusion (risk difference -0.01, 95% confidence interval -0.02-0.00) and subgroup analyses showed that results were consistent across different doses and disease groups. Secondary analysis revealed only six marginally significant adverse events for naltrexone compared to placebo, which were of mild severity.

CONCLUSIONS

Naltrexone does not appear to increase the risk of serious adverse events over placebo. These findings confirm the safety of oral naltrexone when used in licensed indications and encourage investments to undertake efficacy studies in unlicensed indications.

TRIAL REGISTRATION

PROSPERO 2017 CRD42017054421 .

Acceptability of pharmacotherapy for hazardous alcohol use among men who have sex with men: Findings from a qualitative study

INTRODUCTION

Men who have sex with men (MSM) experience high rates of binge drinking, alcohol use disorder (AUD), and alcohol-related health issues. Pharmacotherapy for AUD can reduce hazardous drinking, yet remains underutilized among MSM. This qualitative study examined knowledge and perceptions regarding AUD medications among MSM, with an emphasis on naltrexone.

METHODS

Three focus group discussions (FGDs) with MSM who consumed alcohol in the past year were conducted in February 2015 (N = 39) in the San Francisco Bay Area. The FGD guide generated discussions about hazardous drinking, the social contexts of drinking, and alcohol reduction and cessation options, including pharmacotherapy. Interviews were analyzed via directed content analysis to codify themes.

RESULTS

For participants, drinking at LGBTQ bars was an important social activity. Many expressed interest in reducing alcohol use, but few had heard of pharmacotherapy for AUD. Potential uptake was limited by perceptions of disulfiram as the prototype medication, side effects associated with disulfiram, and concerns that medications do not address alcohol-related stigma or social drivers of drinking. Participants were more receptive to pharmacotherapy when presented with medication options that did not require abstinence. Participants reported being more likely to try pharmacotherapy as part of a peer group or treatment program.

CONCLUSIONS

Efforts to increase the knowledge and availability of naltrexone and harm reduction approaches, while addressing addiction- and medication-related stigma, might improve pharmacotherapy uptake for AUD and decrease hazardous drinking among MSM for whom alcohol holds social significance.

Correlates of viral suppression among HIV-infected men who have sex with men and transgender women in Lima, Peru

In Peru, HIV is concentrated among men who have sex with men (MSM) and transgender women (TGW). Between June 2015 and August 2016, 591 HIV-positive MSM and TGW were recruited at five clinical care sites in Lima, Peru. We found that 82.4% of the participants had achieved viral suppression (VS; VL < 200) and 73.6% had achieved maximal viral suppression (MVS; VL < 50). Multivariable modeling indicated that patients reporting transportation as a barrier to HIV care were less likely to achieve VS (aOR = 0.47; 95% CI = 0.30-0.75) and MVS (aOR = 0.56; 95% CI = 0.37-0.84). Alcohol use disorders were negatively associated with MVS (aOR = 0.62; 95% CI = 0.30-0.75) and age was positively associated with achieving MVS (aOR = 1.29; 95% CI = 1.04-1.59). These findings underscore the need for more accessible HIV care with integrated behavioral health services in Lima, Peru.

Do Subjective Alcohol Screening Tools Correlate with Biomarkers Among High-Risk Transgender Women and Men Who Have Sex with Men in Lima, Peru?

Alcohol abuse can influence sexual risk behavior; however, its measurement is not straightforward. This study compared self-reported alcohol use, via the AUDIT and CAGE, with levels of phosphatidylethanol (Peth), a phospholipid biomarker that forms with chronic, heavy drinking, among high-risk MSM and TW in Lima, Peru. Chi square, Fisher's exact, Wilcoxon ranksum tests compared the instruments. Receiver operating curves determined sensitivity and specificity of the self-reported measures. Among 69 MSM and 17 TW, PEth was positive for 86% (95% CI 77-93%) of participants, while 67% reported binge-drinking in the last 2 weeks. The AUDIT classified 25% as hazardous drinkers while CAGE identified 6% as problem drinkers. Self-reported binge drinking was more sensitive than the AUDIT for PEth positivity (71% vs. 27%, p = 0.022). Among high-risk MSM and TW in Lima, validated, self-report measures of alcohol abuse underestimated biological measures. Further research correlating bio-markers and self-reported alcohol abuse measures is needed.

A Qualitative Assessment of Alcohol Consumption and Sexual Risk Behaviors Among Men Who Have Sex With Men and Transgender Women in Peru

BACKGROUND

Peruvian men who have sex with men (MSM) and transgender women (TGW) experience the double burden of a highly concentrated HIV epidemic with a high prevalence of alcohol use disorders (AUDs). Recent research has associated both with risky sexual behaviors, including unprotected sex, having multiple sexual partners, engaging in sex work, having recent sexually transmitted infections, and having HIV-infected partners. AUDs have also been associated in MSM/TGW with being unaware of HIV+ status.

OBJECTIVES

This study aims to further examine issues associated with alcohol consumption, HIV infection, and risk behaviors in a qualitative analysis of focus groups conducted with MSM/TGW in Peru.

METHODS

A total of 26 MSM/TGW participants with AUDs participated in three semi-structured focus groups in Lima, Peru. Content analysis was facilitated by software, and specific themes were elucidated.

RESULTS

Participants described their drinking patterns, including the types of alcoholic drinks they consumed. They depicted drinking frequently and over multiple-day sessions. Problematic drinking behaviors were described, as well as the perceived characteristics of alcohol dependence. Interestingly, HIV-infected participants who were prescribed antiretroviral therapy did not believe that their drinking affected their medication adherence. These insights can aid in the design of future interventions aiming to reduce problematic drinking as well as HIV-related risk behaviors and, subsequently, HIV incidence.

CONCLUSIONS

Peruvian MSM/TGW exhibit problematic drinking, which may be associated with risky sexual behaviors and HIV transmission. Interest in reducing alcohol consumption was high, suggesting the need for targeted behavioral and pharmacological interventions.

A Systematic Review of Interventions to Reduce Problematic Substance Use Among Transgender Individuals: A Call to Action

Persons who are transgender (i.e., individuals who are assigned one sex at birth, but who do not identify with that sex) are at elevated risk for developing problematic substance use. Recent studies indicate that transgender persons have high rates of alcohol use, illicit drug use, and nonmedical use of prescription drugs and evince more severe misuse of these substances compared with nontransgender individuals. Despite the high rates of substance use among transgender persons and the multiple conceptual and narrative recommendations for substance use treatments, there is a lack of consensus or awareness of empirically tested interventions and programs effective for this population. Thus, it is critical to examine current substance use interventions for transgender individuals to identify gaps in the field and to immediately put forth efforts to reduce problematic substance use. This systematic review is the first to attempt a comprehensive identification and synthesis of the available evidence on interventions for reducing problematic substance use among transgender persons. Reflective of the state of the field regarding transgender care for substance use, we found a deficiency of studies to include in this systematic review (n=2). Perhaps the most important conclusion of this review is that well-designed, theoretically informed culturally sensitive research focused on developing and rigorously testing interventions for substance use among transgender individuals is alarmingly scarce. This review discusses barriers to intervention design and synthesizes treatment recommendations for future work.

Event-level analysis of alcohol consumption and condom use in partnership contexts among men who have sex with men and transgender women in Lima, Peru

BACKGROUND

We explored the association between alcohol use and condomless receptive (CRAI) and insertive (CIAI) anal intercourse within partnership contexts of men who have sex with men (MSM) and transgender women (TGW) in Lima, Peru.

METHODS

From 2012-2014, we surveyed men and TGW (n=1607) who reported anal intercourse with ≥1 male or TGW. Alcohol use with up to 3 sexual partners during the prior 90days was evaluated. Bivariate and multivariate analyses used generalized estimating equations to assess event-level associations between alcohol use, CRAI, CIAI, and partnership characteristics while adjusting for participant clustering from multiple partners.

RESULTS

Of 4774 sexual partnerships reported, 48% were casual, 34% primary, 10% anonymous, and 8% commercial. Alcohol use preceding sex was significantly (p<0.05) associated with CRAI (PR=1.26) and CIAI (PR=1.37). Partnership characteristics significantly associated with alcohol use included commercial sex work (PR=2.21) and trended (p<0.10) towards alcohol use with casual (PR=1.16), transgender (PR=1.48), and moderno ("versatile"; PR=1.17) partners. CRAI and CIAI were more common among participants who reported knowing they (PR=1.52; PR=1.41, respectively) or their partner (PR=1.47; PR=1.44, respectively) was HIV-uninfected. Yet, only CIAI (PR=1.42) was more commonly reported with known HIV-infected partners. Participants who drank alcohol prior to sex were less likely to know their partner's HIV serostatus.

CONCLUSIONS

Alcohol use prior to intercourse was associated with CRAI and CIAI, varied by partnership type, and may impair knowledge of partner HIV serostatus. Detailed knowledge of alcohol use within partner-specific contexts is essential for informing condom-based and alternative HIV prevention strategies for MSM and TGW in Peru.

Impact of alcohol use on sexual behavior among men who have sex with men and transgender women in Lima, Peru

BACKGROUND

Alcohol use disorders (AUDs) may enhance the likelihood of risky sexual behaviors and the acquisition of sexually transmitted infections (STIs). Associations between AUDs with condomless anal intercourse (CAI) and STI/HIV prevalence were assessed among men who have sex with men (MSM) and transgender women (TW) in Lima, Peru.

METHODS

MSM and TW were eligible to participate based on a set of inclusion criteria which characterized them as high-risk. Participants completed a bio-behavioral survey. An AUDIT score ≥8 determined AUD presence. Recent STI diagnosis included rectal gonorrhea/chlamydia, syphilis, and/or new HIV infection within 6 months. Prevalence ratios (PR) were calculated using Poisson regression.

RESULTS

Among 312 MSM and 89 TW, 45% (181/401) had an AUD. Among those with an AUD, 164 (91%) were hazardous/harmful drinkers, and 17 (9%) had alcohol dependence. Higher CAI was reported by participants with an AUD vs. without, (82% vs. 72% albeit not significant). Reporting anal sex in two or more risky venues was associated with screening AUD positive vs. not (24% vs. 15%, p=0.001). There was no difference in recent STI/HIV prevalence by AUD status (32% overall). In multivariable analysis, screening AUD positive was not associated with CAI or recent STI/HIV infection.

CONCLUSIONS

In our sample AUDs were not associated with CAI or new HIV infection/recent STI. However higher prevalence of CAI, alcohol use at last sex, and anal sex in risky venues among those with AUDs suggests that interventions to reduce the harms of alcohol should be aimed toward specific contexts.

Comparison of behavioral characteristics of dogs in the United States and Japan. J Vet Med Sci. 2016;78:231-238. [PMID: 26412048 DOI: 10.1007/s11904-015-0285-5]

This study examined the difference in dog owning between Japan and the United States, and the effect of these differences on dogs' behavioral characteristics. Behavioral evaluations of privately-owned dogs were obtained by using online questionnaire. We compared background and demographic information from the two countries and analyzed the effects of these differences on behavioral characteristics in dogs. The results indicated that there was a bias in the dog breeds kept in Japan compared to the United States and that Japanese dogs' body weight was lower than the US dogs. The main source of dog acquisition was pet stores in Japan and breeders and/or shelters in the United States. Multiple linear regression analysis found that Japanese dogs showed more aggression to household members and higher energy, restlessness and fear of non-social stimuli than US dogs, while US dogs showed more fear of unfamiliar persons, separation-related behavior and excitability. US dogs also showed higher levels of trainability and attachment to owners. The lower dog's body weight was, the higher the behavioral scores except for trainability were. When dogs that were obtained under 3 months of age were analyzed, the younger the dogs were when their owners obtained them, the higher the scores on some behavioral problem factors were. The higher rates of problem behaviors among Japanese dogs compared with US dogs suggest that the preference for small breed dogs and poor early development environment influenced the behavioral characteristics of dogs.