Evolutionary Science as a Method to Facilitate Higher Level Thinking and Reasoning in Medical Training.

Evolutionary science is indispensable for understanding biological processes. Effective medical treatment must be anchored in sound biology. However, currently the insights available from evolutionary science are not adequately incorporated in either pre-medical or medical school curricula. To illuminate how evolution may be helpful in these areas, examples in which the insights of evolutionary science are already improving medical treatment and ways in which evolutionary reasoning can be practiced in the context of medicine are provided. In order to facilitate the learning of evolutionary principles, concepts derived from evolutionary science that medical students and professionals should understand are outlined. These concepts are designed to be authoritative and at the same time easily accessible for anyone with the general biological knowledge of a first-year medical student. Thus we conclude that medical practice informed by evolutionary principles will be more effective and lead to better patient outcomes.Furthermore, it is argued that evolutionary medicine complements general medical training because it provides an additional means by which medical students can practice the critical thinking skills that will be important in their future practice. We argue that core concepts from evolutionary science have the potential to improve critical thinking and facilitate more effective learning in medical training.

Sexual Hookup Culture: A Review.

"Hookups," or uncommitted sexual encounters, are becoming progressively more engrained in popular culture, reflecting both evolved sexual predilections and changing social and sexual scripts. Hook-up activities may include a wide range of sexual behaviors, such as kissing, oral sex, and penetrative intercourse. However, these encounters often transpire without any promise of, or desire for, a more traditional romantic relationship. A review of the literature suggests that these encounters are becoming increasingly normative among adolescents and young adults in North America, representing a marked shift in openness and acceptance of uncommitted sex. We reviewed the current literature on sexual hookups and considered the multiple forces influencing hookup culture, using examples from popular culture to place hooking up in context. We argue that contemporary hookup culture is best understood as the convergence of evolutionary and social forces during the developmental period of emerging adulthood. We suggest that researchers must consider both evolutionary mechanisms and social processes, and be considerate of the contemporary popular cultural climate in which hookups occur, in order to provide a comprehensive and synergistic biopsychosocial view of "casual sex" among emerging adults today.

Change in human social behavior in response to a common vaccine.

PURPOSE: The purpose of this study was to test the hypothesis that exposure to a directly transmitted human pathogen-flu virus-increases human social behavior presymptomatically. This hypothesis is grounded in empirical evidence that animals infected with pathogens rarely behave like uninfected animals, and in evolutionary theory as applied to infectious disease. Such behavioral changes have the potential to increase parasite transmission and/or host solicitation of care. METHODS: We carried out a prospective, longitudinal study that followed participants across a known point-source exposure to a form of influenza virus (immunizations), and compared social behavior before and after exposure using each participant as his/her own control. RESULTS: Human social behavior does, indeed, change with exposure. Compared to the 48 hours pre-exposure, participants interacted with significantly more people, and in significantly larger groups, during the 48 hours immediately post-exposure. CONCLUSIONS: These results show that there is an immediate active behavioral response to infection before the expected onset of symptoms or sickness behavior. Although the adaptive significance of this finding awaits further investigation, we anticipate it will advance ecological and evolutionary understanding of human-pathogen interactions, and will have implications for infectious disease epidemiology and prevention.

Hooking up: gender differences, evolution, and pluralistic ignorance.

"Hooking-up"--engaging in no-strings-attached sexual behaviors with uncommitted partners--has become a norm on college campuses, and raises the potential for disease, unintended pregnancy, and physical and psychological trauma. The primacy of sex in the evolutionary process suggests that predictions derived from evolutionary theory may be a useful first step toward understanding these contemporary behaviors. This study assessed the hook-up behaviors and attitudes of 507 college students. As predicted by behavioral-evolutionary theory: men were more comfortable than women with all types of sexual behaviors; women correctly attributed higher comfort levels to men, but overestimated men's actual comfort levels; and men correctly attributed lower comfort levels to women, but still overestimated women's actual comfort levels. Both genders attributed higher comfort levels to same-gendered others, reinforcing a pluralistic ignorance effect that might contribute to the high frequency of hook-up behaviors in spite of the low comfort levels reported and suggesting that hooking up may be a modern form of intrasexual competition between females for potential mates.

HIV prevention among incarcerated male adolescents in an alternative school setting.

This pilot project tested the feasibility of an evidence-based HIV Intervention Program (HIP) program among 64 male youth, most of whom were African American or Hispanic, in Los Angeles County probation camps. Comparisons were made between adolescents who participated in HIP and a control group on changes in (a) condom use, (b) sexual intercourse under the influence of drugs, (c) knowledge of HIV prevention behaviors, and (d) attitudes toward condom use. Compared to the control group, the intervention group demonstrated significant increases in condom use and significant decreases in their endorsement of the attitude, ''If you want to use a condom, your boy-friend or girlfriend might think you don't trust them.'' These preliminary findings suggest that the HIP program influences key HIV-related constructs among male juvenile offenders.

Evolution for epidemiologists.

Because humans are biological organisms, human health and disease should be understandable within the context of modern evolutionary theory. Although health is not necessarily maximized by evolution and disease is not generally adaptive, a vast amount of human suffering can be captured with relatively few explanatory categories that are consistent with evolutionary logic. Synthesizing epidemiology and evolutionary thinking can generate novel insights into causes and prevention, intervention, and treatment strategies for disease.

Risk behaviors in a rural community with a known point-source exposure to chronic wasting disease.

BACKGROUND: The emergence and continuing spread of Chronic Wasting Disease (CWD) in cervids has now reached 14 U.S. states, two Canadian provinces, and South Korea, producing a potential for transmission of CWD prions to humans and other animals globally. In 2005, CWD spread for the first time from the Midwest to more densely populated regions of the East Coast. As a result, a large cohort of individuals attending a wild game feast in upstate New York were exposed to a deer that was subsequently confirmed positive for CWD. METHODS: Eighty-one participants who ingested or otherwise were exposed to a deer with chronic wasting disease at a local New York State sportsman's feast were recruited for this study. Participants were administered an exposure questionnaire and agreed to follow-up health evaluations longitudinally over the next six years. RESULTS: Our results indicate two types of risks for those who attended the feast, a Feast Risk and a General Risk. The larger the number of risk factors, the greater the risk to human health if CWD is transmissible to humans. Long-term surveillance of feast participants exposed to CWD is ongoing. CONCLUSION: The risk data from this study provide a relative scale for cumulative exposure to CWD-infected tissues and surfaces, and those in the upper tiers of cumulative risk may be most at risk if CWD is transmissible to humans.

An evolutionary model of premenstrual syndrome.

PMS has existed at least since the beginning of medical writing, and is estimated to affect large proportions of women worldwide. But the etiology remains unknown, diagnostic definition and methods vary tremendously, and treatment is wholly symptom-oriented. This poor state of understanding has been attributed to a lack of theoretical perspective. The current work provides such a theoretical perspective from an evolutionary paradigm. PMS is not evolutionarily adaptive in and of itself. Rather, it is part of a cyclic pattern that results from the cessation of heightened, positive physical and sociobehavioral states that are evolutionarily favored during the fertile phase of the menstrual cycle for some women. When the advantage of these positive states diminishes, they cease, causing relatively lower states that are subjectively experienced as symptoms. In its clinical extreme, this is PMS. However, eons of evolution would result in modern women who are choosy about the conditions under which they reproduce. Thus, women whose conditions suggest a high probability of successful immediate reproduction are expected to experience the heightened, positive states during the fertile phase of the menstrual cycle to attract mates and fertilizations; these women will experience symptoms premenstrually. But women whose conditions suggest a low probability of successful immediate reproduction are expected to experience the heightened, positive states during the premenstruum to retain mates, accrue or maintain resources, and/or otherwise improve their conditions; these women will experience symptoms during the fertile phase of the menstrual cycle ("pseudo-PMS"). In addition, the heightened states are expected to shift in response to changes in conditions throughout women's lives, being expressed at whatever point is most evolutionarily beneficial given current conditions. This suggests that our conceptualization of PMS should be reframed within a facultative (condition-sensitive), evolutionary model. It also generates predictions both within- and between women that should elucidate the syndrome.

Methamphetamine users entering treatment: characteristics of the methamphetamine treatment project sample.

The Center for Substance Abuse Treatment funded the Metamphetamine Treatment Project to evaluate and compare treatment approaches for methamphetamine users. As part of this study, drug use patterns, history of physical or sexual abuse, history of suicidality, and psychopathology were assessed in 1,016 methamphetamine-dependent outpatients entering treatment between 1999 and 2001 at eight sites across the western United States. The sample was predominately female and racially diverse. The mean age of the participants was 32.8 years. Most were methamphetamine smokers, but there were marked regional variations. Suicidality and physical or sexual abuse were common and measures of current psychopathology were high. These clinical issues were associated with more frequent use of methamphetamine and, more strongly, with concurrent use of other drugs. Therefore, the relationship between polydrug use and psychopathology in methamphetamine users warrants further investigation.

A comparison of contingency management and cognitive-behavioral approaches for stimulant-dependent individuals.

AIMS: Previous research has reported that both contingency management (CM) and cognitive-behavioral therapy (CBT) are efficacious interventions for the treatment of stimulant abusers. The present study sought to directly compare the effectiveness of (CM) and (CBT) alone and in combination in reducing stimulant use. DESIGN: Randomized clinical trial. PARTICIPANTS: Stimulant-dependent individuals (n = 171). INTERVENTION: CM, CBT or combined CM and CBT, 16-week treatment conditions. CM condition participants received vouchers for stimulant-free urine samples. CBT condition participants attended three 90-minute group sessions each week. MEASUREMENTS: Participants were interviewed at baseline and weeks 17, 26 and 52. Measures included psychiatric disorders and alcohol and drug use and concomitant social problems. FINDINGS: CM procedures produced better retention and lower rates of stimulant use during the study period. Self-reported stimulant use was reduced from baseline levels at all follow-up points for all groups and urinalysis data did not differ between groups at follow-up. While CM produced robust evidence of efficacy during treatment application, CBT produced comparable longer-term outcomes. There was no evidence of an additive effect when the two treatments were combined. CONCLUSIONS: This study suggests that CM is an efficacious treatment for reducing stimulant use and is superior during treatment to a CBT approach. CM is useful in engaging substance abusers, retaining them in treatment and helping them achieve abstinence from stimulant use. CBT also reduces drug use from baseline levels and produces comparable outcomes on all measures at follow-up.

Randomized controlled pilot trial of cabergoline, hydergine and levodopa/carbidopa: Los Angeles Cocaine Rapid Efficacy Screening Trial (CREST).

AIM: This study tested three dopaminergic medications against a common unmatched placebo condition: hydergine 1 mg three times daily (n = 15); levodopa/carbidopa 25/100 mg three times daily (n = 15); cabergoline 0.5 mg per week (n = 15); and placebo three times daily (n = 15) as potential pharmacotherapies for cocaine dependence. DESIGN: The four-parallel group, Cocaine Rapid Efficacy Screening Trial (CREST) design featured a 2-week baseline period followed by randomization to an 8-week medication condition that included 1 hour per week of cognitive behavioral drug counseling. A safety evaluation was conducted 4 weeks after termination. MEASURES: Outcomes included cocaine metabolites measured in urine, retention and self-reports for drug use, cocaine craving, clinical improvement, mood and HIV risk behaviors. RESULTS: Participants assigned to receive cabergoline provided more urine samples negative for cocaine metabolites (42.4%) than those assigned to receive placebo (25.0%), a statistically significant difference after controlling for baseline differences in self-reported cocaine use (F = 2.95, df = 3; P = 0.05). Cabergoline-treated participants demonstrated a significant improvement over placebo from baseline to week 8 when measured using the Addiction Severity Index (ASI) employment subscale (overall change = - 0.09, SD = 0.10, t = 2.36, P < 0.05). Safety and adverse event measures showed similar rates and types of complaints by treatment condition. CONCLUSIONS: These results, combined with the apparent safety of cabergoline when used with this population, provide empirical support for conducting a larger study of the medication.

Bringing buprenorphine-naloxone detoxification to community treatment providers: the NIDA Clinical Trials Network field experience.

In October 2002, the U.S. Food and Drug Administration approved buprenorphine-naloxone (Suboxone) sublingual tablets as an opioid dependence treatment available for use outside traditionally licensed opioid treatment programs. The NIDA Center for Clinical Trials Network (CTN) sponsored two clinical trials assessing buprenorphine-naloxone for short-term opioid detoxification. These trials provided an unprecedented field test of its use in twelve diverse community-based treatment programs. Opioid-dependent men and women were randomized to a thirteen-day buprenorphine-naloxone taper regimen for short-term opioid detoxification. The 234 buprenorphine-naloxone patients averaged 37 years old and used mostly intravenous heroin. Direct and rapid induction onto buprenorphine-naloxone was safe and well tolerated. Most patients (83%) received 8 mg buprenorphine-2 mg naloxone on the first day and 90% successfully completed induction and reached a target dose of 16 mg buprenorphine-4 mg naloxone in three days. Medication compliance and treatment engagement was high. An average of 81% of available doses was ingested, and 68% of patients completed the detoxification. Most (80.3%) patients received some ancillary medications with an average of 2.3 withdrawal symptoms treated. The safety profile of buprenorphine-naloxone was excellent. Of eighteen serious adverse events reported, only one was possibly related to buprenorphine-naloxone. All providers successfully integrated buprenorphine-naloxone into their existing treatment milieus. Overall, data from the CTN field experience suggest that buprenorphine-naloxone is practical and safe for use in diverse community treatment settings, including those with minimal experience providing opioid-based pharmacotherapy and/or medical detoxification for opioid dependence.

A multi-site comparison of psychosocial approaches for the treatment of methamphetamine dependence.

AIMS: The Center for Substance Abuse Treatment (CSAT) Methamphetamine Treatment Project (MTP) is the largest randomized clinical trial of treatments for methamphetamine (MA) dependence to date. The objective of the study was to compare the Matrix Model, a manualized treatment method, with treatment-as-usual (TAU) in eight community out-patient settings in the Western United States. DESIGN: Over an 18-month period between 1999 and 2001, 978 treatment-seeking, MA-dependent people were randomly assigned to receive either TAU at each site or a manualized 16-week treatment (Matrix Model). SETTING: The study was conducted as an eight-site out-patient trial, with six sites located in California and one each in Montana and Hawaii. FINDINGS: In the overall sample, and in the majority of sites, those who were assigned to Matrix treatment attended more clinical sessions, stayed in treatment longer, provided more MA-free urine samples during the treatment period and had longer periods of MA abstinence than those assigned to receive TAU. Measures of drug use and functioning collected at treatment discharge and 6 months post-admission indicate significant improvement by participants in all sites and conditions when compared to baseline levels, but the superiority of the Matrix approach did not persist at these two timepoints. CONCLUSIONS: Study results demonstrate a significant initial step in documenting the efficacy of the Matrix approach. Although the superiority of the Matrix approach over TAU was not maintained at the post-treatment timepoints, the in-treatment benefit is an important demonstration of empirical support for this psychosocial treatment approach.

Abuse and violence history of men and women in treatment for methamphetamine dependence.

The Methamphetamine Treatment Project offers the opportunity to examine the history of abuse and violence in a sample of 1016 methamphetamine users participating in a multisite study between 1999-2001. Reporting of abuse and violence was extensive, with 80% of women reporting abuse or violence from a partner. Men were more likely to report experiencing violence from friends and others. A high percentage of study participants reported a variety of threatening or coercive experiences with their partners. Past and current interpersonal violence is a characteristic of the lifestyles of the majority entering treatment for methamphetamine dependence.

A comparison of contingency management and cognitive-behavioral approaches during methadone maintenance treatment for cocaine dependence.

BACKGROUND: This study compared 2 psychosocial approaches for the treatment of cocaine dependence: contingency management (CM) and cognitive-behavioral therapy (CBT). METHODS: Patients with cocaine dependence who were receiving methadone maintenance treatment (n = 120) were randomly assigned to 1 of 4 conditions: CM, CBT, combined CM and CBT (CBT + CM), or treatment as usual (ie, methadone maintenance treatment program only [MMTP only]) (n = 30 per cell). The CM procedures and CBT materials were comparable to those used in previously published research. The active study period was 16 weeks, requiring 3 clinic visits per week. Participants were evaluated during treatment and at 17, 26, and 52 weeks after admission. RESULTS: Urinalysis results during the 16-week treatment period show that participants assigned to the 2 groups featuring CM had significantly superior in-treatment urinalysis results, whereas urinalysis results from participants in the CBT group were not significantly different than those from the MMTP-only group. At week 17, self-reported days of cocaine use were significantly reduced from baseline levels for all 3 treatment groups but not for the MMTP-only group. At the 26-week and 52-week follow-up points, CBT participants showed substantial improvement, resulting in equivalent performance with the CM groups as indicated by both urinalysis and self-reported cocaine use data. CONCLUSIONS: Study findings provide solid evidence of efficacy for CM and CBT. Although the effect of CM is significantly greater during treatment, CBT appears to produce comparable long-term outcomes. There was no evidence of an additive effect for the 2 treatments in the CM + CBT group.

Predicting treatment success at multiple timepoints in diverse patient populations of cocaine-dependent individuals.

The quest for predictive utility of baseline demographic and drug use characteristics has been difficult. The present article draws data from two studies of cocaine-dependent individuals (N = 297) in treatment at clinics in Los Angeles, and examines the utility of socio-demographic characteristics of patients and in-treatment performance variables as predictors of success at treatment end, 6 and 12 month follow-up assessments. Socio-demographic variables examined are age, gender, ethnicity, and educational attainment; drug use variables include years of cocaine use, self-reported days of cocaine use, the Addiction Severity Index drug composite score, and two composite measures cited in the literature. The in-treatment variables examined include cocaine urine toxicology results, number of weeks retained, and measures of compliance. The self-reported number of days of cocaine use in the past 30 days provides the most predictive utility of all baseline variables evaluated, and is the most parsimonious of the significant variables associated with substance use at all subsequent timepoints. Matching cocaine-dependent patients with treatment types or intensities based on the self-reported number of cocaine use days at intake may increase patient success rates.

Drugs and sexual effects: role of drug type and gender.

This study investigated gender differences in the relationship between psychoactive substance use and sexual thoughts, feelings, and behaviors. Participants (N = 464) were male and female alcohol, opiate, cocaine, and methamphetamine users enrolled in an outpatient treatment program at any of 8 sites. A self-report survey that inquired about the specific sexual thoughts, feelings, and behaviors of the participant during previous instances of being under the influence of their primary drug of dependence served as the data source. The results indicate that different categories of psychoactive agents were associated with different effects on sexual behavior, and that those effects vary by gender. Development of a valid measure assessing the type and strength of these relationships may be beneficial for use by treatment programs in promoting abstinence from drug and alcohol use and preventing relapse.