New Zealand Women's Experience of Intimacy Within Heterosexual Relationships: Influence of Partners' Perceived Pornography Use.

The association between women's levels of relationship intimacy and how frequently their partner viewed pornography was examined in a community sample of 136 NZ heterosexual women. Controlling for age, ethnicity and education, partner use of pornography was significantly negatively correlated with emotional, sexual, intellectual and recreational intimacy, but not social intimacy. Women's attitudes toward pornography did not mediate any of these associations. However, significant moderation effects were found: women with more negative attitudes toward pornography reported lower rates of emotional and social intimacy when their partner was believed to be viewing pornography weekly or more, but not when this frequency was less. No association was found for women with less negative attitudes toward pornography. These findings indicate that pornography may be detrimental to relationship intimacy for women with strongly negative attitudes toward it.

Development and Validation of a Brief Measure of Eating Compulsivity (MEC).

Food addiction is increasingly being recognised as a contributory factor in overweight and obesity. Management of eating compulsivity, a key component of food addiction, may assist greatly in the successful treatment of obesity. Measurement of food addiction and its core characteristic of eating compulsivity is fundamental to increasing understandings of the concept of food addiction, its prevalence among people with and without obesity and its utility within a treatment context. The current study describes the development and initial validation of a brief measure of eating compulsivity that can be used within clinical and research settings to establish a person's level of eating compulsivity. Sixty five participants with a BMI ≥30 (mean BMI 38.1) were recruited from a general population sample within Christchurch, New Zealand. Participants completed the test version of the Measure of Eating Compulsivity (MEC) and the Yale Food Addiction Scale (YFAS) as well as providing self-reported measures of height and weight. The 10-item MEC was developed. This measure was shown to have excellent internal consistency (Cronbach's alpha =.946), based on a single factor accounting for 67.4% of the variance and excellent test-retest reliability (r =.923). MEC10 score was strongly predictive of being categorised as having food addiction based on the YFAS, although not associated with BMI. This brief tool is likely to have high utility in clinical and research settings and requires further validation with a range of populations including those with and without obesity, binge eating disorder and other eating disorders.

Personality Predictors of Drinking Outcomes in Depressed Alcohol-Dependent Patients.

AIM: To evaluate the role of personality dimensions as predictors of drinking outcomes in depressed alcohol-dependent patients. METHODS: Temperament and character inventory (TCI) scores were obtained at baseline in a 24-week study of 127 depressed alcohol-dependent patients who received open-label naltrexone and were randomized to citalopram or placebo. The association between TCI personality dimensions and alcohol outcomes during follow-up was examined using general linear mixed models. RESULTS: Low novelty seeking, high self-directedness and high cooperativeness predicted less alcohol consumption on drinking days during follow-up. Temperament and character variables had no effect on the percentage of days abstinent from alcohol. Depression mediated the effects of self-directedness and cooperativeness on alcohol outcomes while the effect of novelty seeking remained after adjusting for depression scores in follow-up. CONCLUSION: Identifying personality characteristics at baseline predicts drinking outcomes in depressed, alcohol-dependent patients. In particular patients with high novelty seeking drank more heavily on drinking days and they may therefore need more intensive intervention to achieve good treatment outcomes.

OPRM1 genotype and naltrexone response in depressed alcohol-dependent patients.

A functional polymorphism rs1799971 (A118G) in the µ-opioid receptor gene (OPRM1) produces an amino acid substitution Asn40Asp, which is believed to influence naltrexone response in nondepressed alcohol-dependent patients. In this study, patients with alcohol dependence and major depression (n=108) received open-label naltrexone and clinical case management for 12 weeks, and were randomized to citalopram or placebo. General linear mixed models examined the effect of the OPRM1 A118G genotype on alcohol outcomes during treatment. There was no evidence of any difference in the percentage of days abstinent, drinks per drinking day or percentage of heavy drinking days between Asp40 carriers and noncarriers during treatment. This study therefore failed to replicate the previous positive findings for this single nucleotide polymorphism in relation to naltrexone response, possibly indicating that the effect is not present in depressed patients.

A randomized trial of combined citalopram and naltrexone for nonabstinent outpatients with co-occurring alcohol dependence and major depression.

Despite the high rate of co-occurrence of major depression and alcohol dependence, the role of pharmacotherapy in their treatment remains unclear. In the new era of naltrexone for alcohol dependence, it is notable that only 1 study to date has examined the efficacy of antidepressant medication prescribed concurrently with naltrexone. We aimed to determine whether combining naltrexone with citalopram produced better treatment outcomes than naltrexone alone in patients with co-occurring alcohol dependence and depression, and to investigate whether either sex or depression type (independent or substance-induced depression) moderated treatment response. Participants were 138 depressed alcohol-dependent adults who were not required to be abstinent at the commencement of the trial. They were randomized to 12 weeks of citalopram or placebo, plus naltrexone and clinical case management. Treatment was well attended, and medications were reasonably well tolerated with high adherence rates. Substantial improvements in both mood and drinking occurred in both groups, with no significant differences between groups on any of the mood or drinking outcome measures, whether or not other variables were controlled for. No interaction effect was found for independent/substance-induced depression status, whereas there was a marginal effect found by sex, with greater improvement in 1 drinking outcome measure (percent days abstinent) in women taking citalopram. These findings suggest that citalopram is not a clinically useful addition to naltrexone and clinical case management in this treatment population. Independent/substance-induced depression status did not predict treatment response. Findings for sex were equivocal.

Combination rapid-acting nicotine mouth spray and nicotine patch therapy in smoking cessation.

INTRODUCTION: Improved smoking cessation rates are urgently required if New Zealand is to reach its target of a smokefree nation by 2025, during which some 600,000 smokers will need to quit. Nicotine replacement therapy remains a core part of the pharmacological approach to smoking cessation. Oral nicotine solutions with rapid onset have recently become available. We have examined the effect of a nicotine spray and a nicotine patch on smoking cessation for 12 months. METHODS: We enrolled potential participants-smokers wanting to quit aged 18-70 years, who smoked ≥9 cigarettes per day-with Fagerström Test of Nicotine Dependence score ≥3 in a double-blind trial in 3 trial sites. Smokers were randomized to a nicotine or placebo spray for 6 months, and all received nicotine patches daily for 5 months. They were followed at regular intervals for 12 months. RESULTS: A total of 1,423 subjects were randomized to nicotine oral spray (1mg of nicotine free base per spray) plus nicotine patch or a placebo spray and nicotine patch. The nicotine mouth spray plus nicotine patch showed significant improvements in prolonged abstinence for all measures to 6 months (7 consecutive days at each visit for 6 months: 15.5% vs. 10.6%; p = .006) for the combination versus placebo and nicotine patch. Thereafter, the differences were not significant. CONCLUSIONS: The addition of a nicotine mouth spray to a nicotine replacement patch in a population of smokers receiving a low level of behavioral support improved early quitting, but the effects were not sustained.

The New Zealand drug harms ranking study: A multi-criteria decision analysis.

AIMS: The harms arising from psychoactive drug use are complex, and harm reduction strategies should be informed by a detailed understanding of the extent and nature of that harm. Drug harm is also context specific, and so any comprehensive assessment of drug harm should be relevant to the characteristics of the population in question. This study aimed to evaluate and rank drug harms within Aotearoa New Zealand using a multi-criteria decision analysis (MCDA) framework, and to separately consider harm within the total population, and among youth. METHODS: Two facilitated workshops involved the separate ranking of harm for the total population, and then for youth aged 12-17, by two expert panels. In the total population workshop, 23 drugs were scored against 17 harm criteria, and those criteria were then evaluated using a swing weighting process. Scoring and weighting were subsequently updated during the youth-specific workshop. All results were recorded and analysed using specialised MCDA software. RESULTS: When considering overall harm, the MCDA modelling results indicated that alcohol, methamphetamine and synthetic cannabinoids were the most harmful to both the overall population and the youth, followed by tobacco in the total population. Alcohol remained the most harmful drug for the total population when separately considering harm to those who use it, and harm to others. CONCLUSIONS: The results provide detailed and context-specific insight into the harm associated with psychoactive drugs use within Aotearoa New Zealand. The findings also demonstrate the value of separately considering harm for different countries, and for different population subgroups.

Activin type I receptor polymorphisms and body composition in older individuals with sarcopenia-Analyses from the LACE randomised controlled trial.

BACKGROUND: Ageing is associated with changes in body composition including an overall reduction in muscle mass and a proportionate increase in fat mass. Sarcopenia is characterised by losses in both muscle mass and strength. Body composition and muscle strength are at least in part genetically determined, consequently polymorphisms in pathways important in muscle biology (e.g., the activin/myostatin signalling pathway) are hypothesised to contribute to the development of sarcopenia. METHODS: We compared regional body composition measured by DXA with genotypes for two polymorphisms (rs10783486, minor allele frequency (MAF) = 0.26 and rs2854464, MAF = 0.26) in the activin 1B receptor (ACVR1B) determined by PCR in a cross-sectional analysis of DNA from 110 older individuals with sarcopenia from the LACE trial. RESULTS: Neither muscle mass nor strength showed any significant associations with either genotype in this cohort. Initial analysis of rs10783486 showed that males with the AA/AG genotype were taller than GG males (174±7cm vs 170±5cm, p = 0.023) and had higher arm fat mass, (median higher by 15%, p = 0.008), and leg fat mass (median higher by 14%, p = 0.042). After correcting for height, arm fat mass remained significantly higher (median higher by 4% padj = 0.024). No associations (adjusted or unadjusted) were seen in females. Similar analysis of the rs2854464 allele showed a similar pattern with the presence of the minor allele (GG/AG) being associated with greater height (GG/AG = 174±7 cm vs AA = 170 ±5cm, p = 0.017) and greater arm fat mass (median higher by 16%, p = 0.023). Again, the difference in arm fat remained after correction for height. No similar associations were seen in females analysed alone. CONCLUSION: These data suggest that polymorphic variation in the ACVR1B locus could be associated with body composition in older males. The activin/myostatin pathway might offer a novel potential target to prevent fat accumulation in older individuals.

ACE I/D genotype associates with strength in sarcopenic men but not with response to ACE inhibitor therapy in older adults with sarcopenia: Results from the LACE trial.

BACKGROUND: Angiotensin II (AII), has been suggested to promote muscle loss. Reducing AII synthesis, by inhibiting angiotensin converting enzyme (ACE) activity has been proposed as a method to inhibit muscle loss. The LACE clinical trial was designed to determine whether ACE inhibition would reduce further muscle loss in individuals with sarcopenia but suffered from low recruitment and returned a negative result. Polymorphic variation in the ACE promoter (I/D alleles) has been associated with differences in ACE activity and muscle physiology in a range of clinical conditions. This aim of this analysis was to determine whether I/D polymorphic variation is associated with muscle mass, strength, in sarcopenia or contributed to the lack of response to treatment in the LACE study. METHODS: Sarcopenic individuals were recruited into a 2x2 factorial multicentre double-blind study of the effects of perindopril and/or leucine versus placebo on physical performance and muscle mass. DNA extracted from blood samples (n = 130 72 women and 58 men) was genotyped by PCR for the ACE I/D polymorphism. Genotypes were then compared with body composition measured by DXA, hand grip and quadriceps strength before and after 12 months' treatment with leucine and/or perindopril in a cross-sectional analysis of the influence of genotype on these variables. RESULTS: Allele frequencies for the normal UK population were extracted from 13 previous studies (I = 0.473, D = 0.527). In the LACE cohort the D allele was over-represented (I = 0.412, D = 0.588, p = 0.046). This over-representation was present in men (I = 0.353, D = 0.647, p = 0.010) but not women (I = 0.458, D = 0.532, p = 0.708). In men but not women, individuals with the I allele had greater leg strength (II/ID = 18.00 kg (14.50, 21.60) vs DD = 13.20 kg (10.50, 15.90), p = 0.028). Over the 12 months individuals with the DD genotype increased in quadriceps strength but those with the II or ID genotype did not. Perindopril did not increase muscle strength or mass in any polymorphism group relative to placebo. CONCLUSION: Our results suggest that although ACE genotype was not associated with response to ACE inhibitor therapy in the LACE trial population, sarcopenic men with the ACE DD genotype may be weaker than those with the ACE I/D or II genotype.

Effect of perindopril or leucine on physical performance in older people with sarcopenia: the LACE randomized controlled trial.

BACKGROUND: This trial aimed to determine the efficacy of leucine and/or perindopril in improving physical function in older people with sarcopenia. METHODS: Placebo-controlled, parallel group, double-blind, randomized two-by-two factorial trial. We recruited adults aged ≥ 70 years with sarcopenia, defined as low gait speed (<0.8 m/s on 4 m walk) and/or low handgrip strength (women < 20 kg, men < 30 kg) plus low muscle mass (using sex and body mass index category-specific thresholds derived from normative UK BioBank data) from 14 UK centres. Eligible participants were randomized to perindopril 4 mg or placebo, and to oral leucine powder 2.5 g or placebo thrice daily. The primary outcome was the between-group difference in the short physical performance battery (SPPB) score over 12-month follow-up by repeated-measures mixed models. Results were combined with existing systematic reviews using random-effects meta-analysis to derive summary estimates of treatment efficacy. RESULTS: We screened 320 people and randomized 145 participants compared with an original target of 440 participants. For perindopril [n = 73, mean age 79 (SD 6), female sex 39 (53%), mean SPPB 7.1 (SD 2.3)] versus no perindopril [n = 72, mean age 79 (SD 6), female sex 39 (54%), mean SPPB 6.9 (SD 2.4)], median adherence to perindopril was lower (76% vs. 96%; P < 0.001). Perindopril did not improve the primary outcome [adjusted treatment effect -0.1 points (95%CI -1.2 to 1.0), P = 0.89]. No significant treatment benefit was seen for any secondary outcome including muscle mass [adjusted treatment effect -0.4 kg (95%CI -1.1 to 0.3), P = 0.27]. More adverse events occurred in the perindopril group (218 vs. 165), but falls rates were similar. For leucine [n = 72, mean age 78 (SD 6), female sex 38 (53%), mean SPPB 7.0 (SD 2.1)] versus no leucine [n = 72, mean age 79 (SD 6), female sex 40 (55%), mean SPPB 7.0 (SD 2.5)], median adherence was the same in both groups (76% vs. 76%; P = 0.99). Leucine did not improve the primary outcome [adjusted treatment effect 0.1 point (95%CI -1.0 to 1.1), P = 0.90]. No significant treatment benefit was seen for any secondary outcome including muscle mass [adjusted treatment effect -0.3 kg (95%CI -1.0 to 0.4), P = 0.47]. Meta-analysis of angiotensin converting enzyme inhibitor/angiotensin receptor blocker trials showed no clinically important treatment effect for the SPPB [between-group difference -0.1 points (95%CI -0.4 to 0.2)]. CONCLUSIONS: Neither perindopril nor leucine improved physical performance or muscle mass in this trial; meta-analysis did not find evidence of efficacy of either ACE inhibitors or leucine as treatments to improve physical performance.

Dipeptidyl peptidase-1 inhibition in patients hospitalised with COVID-19: a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial.

BACKGROUND: Neutrophil serine proteases are involved in the pathogenesis of COVID-19 and increased serine protease activity has been reported in severe and fatal infection. We investigated whether brensocatib, an inhibitor of dipeptidyl peptidase-1 (DPP-1; an enzyme responsible for the activation of neutrophil serine proteases), would improve outcomes in patients hospitalised with COVID-19. METHODS: In a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial, across 14 hospitals in the UK, patients aged 16 years and older who were hospitalised with COVID-19 and had at least one risk factor for severe disease were randomly assigned 1:1, within 96 h of hospital admission, to once-daily brensocatib 25 mg or placebo orally for 28 days. Patients were randomly assigned via a central web-based randomisation system (TruST). Randomisation was stratified by site and age (65 years or ≥65 years), and within each stratum, blocks were of random sizes of two, four, or six patients. Participants in both groups continued to receive other therapies required to manage their condition. Participants, study staff, and investigators were masked to the study assignment. The primary outcome was the 7-point WHO ordinal scale for clinical status at day 29 after random assignment. The intention-to-treat population included all patients who were randomly assigned and met the enrolment criteria. The safety population included all participants who received at least one dose of study medication. This study was registered with the ISRCTN registry, ISRCTN30564012. FINDINGS: Between June 5, 2020, and Jan 25, 2021, 406 patients were randomly assigned to brensocatib or placebo; 192 (47·3%) to the brensocatib group and 214 (52·7%) to the placebo group. Two participants were excluded after being randomly assigned in the brensocatib group (214 patients included in the placebo group and 190 included in the brensocatib group in the intention-to-treat population). Primary outcome data was unavailable for six patients (three in the brensocatib group and three in the placebo group). Patients in the brensocatib group had worse clinical status at day 29 after being randomly assigned than those in the placebo group (adjusted odds ratio 0·72 [95% CI 0·57-0·92]). Prespecified subgroup analyses of the primary outcome supported the primary results. 185 participants reported at least one adverse event; 99 (46%) in the placebo group and 86 (45%) in the brensocatib group. The most common adverse events were gastrointestinal disorders and infections. One death in the placebo group was judged as possibly related to study drug. INTERPRETATION: Brensocatib treatment did not improve clinical status at day 29 in patients hospitalised with COVID-19. FUNDING: Sponsored by the University of Dundee and supported through an Investigator Initiated Research award from Insmed, Bridgewater, NJ; STOP-COVID19 trial.

Validation of the French version of the Cannabis Use Disorder Identification Test-Revised and comparison with the Cannabis Abuse Screening Test for screening cannabis use disorder in a psychiatric sample.

INTRODUCTION: Several questionnaires have been developed for screening cannabis use disorder in clinical populations, but very few studies have compared the screening abilities of the different instruments. Here, we aimed to confirm the psychometric properties of a French version of the Cannabis Use Disorder Identification Test-Revised (CUDIT-R), and to compare its screening abilities with those of the Cannabis Abuse Screening Test (CAST), in subjects consulting in mental health settings. METHODS: Two hundred and thirteen cannabis smokers who sought treatment for any type of mental disorder, recruited in four French centres, completed the French CUDIT-R (CUDIT-R-Fr) and the full version of the CAST, and were assessed for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria of cannabis use disorder by an addiction specialist. They were retested with the CUDIT-R-Fr after approximately a week. The factorial construct validity, internal consistency and test-retest reliability of the CUDIT-R-Fr were assessed. The compared sensitivity and specificity of the CAST and CUDIT-R-Fr were explored, using the clinician assessment as the reference. RESULTS: The French CUDIT-R showed a good internal consistency (Cronbach's alpha = 0.89) and an excellent test-retest reliability (ρ = 0.97). The sensitivity and specificity for screening cannabis use disorder were 0.81 and 0.77 for the CUDIT-R, and 0.92 and 0.63 for the CAST, respectively. CONCLUSIONS: Based on the recommended cut-offs, the CAST appeared more sensitive, while the CUDIT-R was more specific, for screening cannabis use disorder in a population of cannabis users with heterogeneous types of mental health disorders.

Initial preference for drinking goal in the treatment of alcohol problems: I. Baseline differences between abstinence and non-abstinence groups.

AIMS: To compare baseline characteristics of clients initially preferring abstinence with those preferring non-abstinence at the screening stage of a randomized controlled trial of treatment for alcohol problems (UKATT) and to identify predictors of goal preference from client characteristics present before the preference was stated. METHODS: From discussions with clients entering the trial (N = 742), screeners noted whether clients were aiming for abstinence 'probably yes' or 'probably no'. Differences between the two groups thus formed were explored by univariate comparisons among client characteristics recorded at baseline assessment and by logistic regression analysis with pre-existing characteristics as independent variables. RESULTS: Across all UKATT sites, 54.3% of clients expressed a preference for abstinence and 45.7% for non-abstinence. In univariate comparisons, clients preferring abstinence were significantly (P < 0.01) more likely to: (i) be female, (ii) be unemployed, (iii) report drinking more heavily but less frequently, (iv) have been detoxified in the 2 weeks prior to assessment, (v) report more alcohol problems, (vi) be in the action stage of change, (vii) report greater negative expectancies of drinking, (viii) report greater mental and physical ill-health, (ix) report less social support for drinking and (x) be more confident of their ability to resist heavy drinking in tempting situations. In the logistic regression model, the strongest predictors of goal preference were gender, drinking pattern, recent detoxification and social support for drinking. CONCLUSION: The implications of these findings for service delivery are best considered in conjunction with findings from a companion paper reporting treatment outcomes associated with each goal preference.

Initial preference for drinking goal in the treatment of alcohol problems: II. Treatment outcomes.

AIMS: To compare treatment outcomes between clients preferring abstinence and those preferring non-abstinence at the screening stage of a randomized controlled trial of treatment for alcohol problems (the United Kingdom Alcohol Treatment Trial) and to interpret any differential outcome in light of baseline differences between goal preference groups outlined in an accompanying paper. METHODS: Outcomes at 3 and 12 months' follow-up were recorded both in categorical terms (abstinence/non-problem drinking/much improved/somewhat improved/same/worse) and on continuous measures (percent days abstinent, drinks per drinking day/dependence score). RESULTS: Clients initially stating a preference for abstinence showed a better outcome than those stating a preference for non-abstinence. This superior outcome was clearer at 3 months' follow-up but still evident at 12 months' follow-up. The better outcome consisted almost entirely in a greater frequency of abstinent days, with only a modest benefit in drinking intensity for goal abstainers that disappeared when baseline covariates of goal preference were controlled for. Type of successful outcome (abstinence/non-problem drinking) was related to initial goal preference, with clients preferring abstinence more likely to obtain an abstinent outcome and those preferring non-abstinence a non-problem drinking outcome. CONCLUSION: The client's personal drinking goals should be discussed in assessment at treatment entry and as a basis for negotiation. Clinicians should be prepared to identify and support goal change as an unexceptional part of the treatment process that need not jeopardize good outcome.

Client language during motivational enhancement therapy and alcohol use outcome.

BACKGROUND: The exact link between the process engaged in during Motivational Interviewing based interventions, such as Motivational Enhancement Therapy (MET), and outcome is yet to be fully understood. AIMS: This preliminary study examined Client Language during MET and outcome. METHOD: A modified Motivational Interviewing Skills Code Version 2.0 was used to code 106 audiotaped MET sessions from 28 participants who received 3-4 sessions of MET within the context of a randomized controlled trial for mild-moderate alcohol dependence. Client Language was analyzed within sessions (categorized into Early, Mid, or End Intervals) and across sessions, and in relation to six month drinking outcome (drinking within/over national drinking guidelines, i.e. Remitted/Unremitted Drinkers). RESULTS: Unremitted Drinkers uttered a significantly higher frequency of Sustain Talk, lower Ability Language strength (over all MET and during End Intervals), and lower Commitment Language strength (during Session 2 and 4, and change over MET). CONCLUSIONS: Notwithstanding limitations, this exploratory study was unique in examining the strength of Client Language within and across sessions. It produced potentially valuable findings that warrant further investigation including supporting the clinical benefit of monitoring Client Language to predict outcome.

The Impact of Sprint Interval Training Frequency on Blood Glucose Control and Physical Function of Older Adults.

Exercise is a powerful tool for improving health in older adults, but the minimum frequency required is not known. This study sought to determine the effect of training frequency of sprint interval training (SIT) on health and physical function in older adults. Thirty-four (13 males and 21 females) older adults (age 65 ± 4 years) were recruited. Participants were allocated to a control group (CON n = 12) or a once- (n = 11) or twice- (n = 11) weekly sprint interval training (SIT) groups. The control group maintained daily activities; the SIT groups performed 8 weeks of once- or twice-weekly training sessions consisting of 6 s sprints. Metabolic health (oral glucose tolerance test), aerobic capacity (walk test) and physical function (get up and go test, sit to stand test) were determined before and after training. Following training, there were significant improvements in blood glucose control, physical function and aerobic capacity in both training groups compared to control, with changes larger than the smallest worthwhile change. There was a small to moderate effect for blood glucose (d = 0.43-0.80) and physical function (d = 0.43-0.69) and a trivial effect for aerobic capacity (d = 0.01) between the two training frequencies. Once a week training SIT is sufficient to produce health benefits. Therefore, the minimum time and frequency of exercise required is much lower than currently recommended.

Drug use and addiction: evolutionary perspective.

Drug use creates a significant amount of harm in modern societies. From an evolutionary perspective, the pervasive use of drugs and the ongoing risk of drug addiction can be explained in terms of the action of drugs on evolved motivational-emotional systems. Addiction arises through interaction of these evolutionarily ancient systems, designed to promote the pursuit of natural rewards, and contemporary environments where purified and potent forms of drugs are readily available. This evolutionary analysis is extended to account for developmental patterns in problem drug use, and to explain the existence of behavioural addictions, such as problem gambling. The paper concludes by considering some of the clinical and public policy implications of the evolutionary perspective presented.