A direct comparison of the behavioral and physiological effects of methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) in humans

Effects of L-methamphetamine treatment on cocaine- and food-maintained behavior in rhesus monkeys

RATIONALE

Monoamine releasers with prominent dopaminergic actions, e.g., D-methamphetamine (D-MA), significantly reduce cocaine use and craving in clinical and preclinical laboratory studies. However, D-MA and related drugs also display high abuse potential, which limits their acceptability as agonist replacement medications for the management of Cocaine Use Disorder.

OBJECTIVES

The L-isomer of methamphetamine (L-MA), unlike D-MA, has preferential noradrenergic actions and is used medicinally with low, if any, abuse liability. The present study was conducted to determine whether L-MA could serve as an agonist replacement medication by both mimicking interoceptive effects of cocaine and decreasing intravenous (IV) cocaine self-administration.

METHODS

Separate groups (N = 4-5) of rhesus monkeys were studied to determine whether L-MA could (1) substitute for cocaine in subjects that discriminated intramuscular (IM) cocaine (0.4 mg/kg) from saline and (2) decrease IV cocaine self-administration under a second-order FR2(VR16:S) schedule of reinforcement.

RESULTS

L-MA, like D-MA but with approximately 5-fold lesser potency, substituted for cocaine in drug discrimination experiments in a dose-dependent manner. In IV self-administration studies, 5-10-day treatments with continuously infused L-MA (0.032-0.32 mg/kg/h, IV) dose-dependently decreased cocaine-maintained responding; the highest dosage reduced cocaine intake to levels of saline self-administration without appreciable effects on food-maintained responding.

CONCLUSIONS

These results indicate that L-MA both shares discriminative stimulus effects with cocaine and reduces cocaine self-administration in a behaviorally selective manner. L-MA and other compounds with a similar pharmacological profile deserve further evaluation for the management of Cocaine Use Disorder.

Boundary conditions of methamphetamine craving

Methamphetamine use has increased significantly and become a global health concern. Craving is known to predict methamphetamine use and relapse following abstinence. Some have suggested that cravings are automatic, generalized, and uncontrollable, but experimental work addressing these claims is lacking. In 2 exploratory studies, we tested the boundary conditions of methamphetamine craving by asking: (a) is craving specific to users' preferred route of administration?, and (b) can craving be regulated by cognitive strategies? Two groups of methamphetamine users were recruited. In Study 1, participants were grouped by their preferred route of administration (intranasal vs. smoking), and rated their craving in response to photographs and movies depicting methamphetamine use (via the intranasal vs. smoking route). In Study 2, methamphetamine smokers implemented cognitive regulation strategies while viewing photographs depicting methamphetamine smoking. Strategies involved either focusing on the positive aspects of smoking methamphetamine or the negative consequences of doing so-the latter strategy based on treatment protocols for addiction. In Study 1, we found a significant interaction between group and route of administration, such that participants who preferred to smoke methamphetamine reported significantly stronger craving for smoking stimuli, whereas those who preferred the intranasal route reported stronger craving for intranasal stimuli. In Study 2, participants reported significantly lower craving when focusing on the negative consequences associated with methamphetamine use. Taken together, these findings suggest that strength of craving for methamphetamine is moderated by users' route of administration and can be reduced by cognitive strategies. This has important theoretical, methodological, and clinical implications.

Application of the Passionate Attachment Model to Recreational Use of MDMA/Ecstasy

Those who are not addicted to ecstasy, but who use it persistently over time, could be viewed as having a "passionate attachment" to a highly valued activity. To evaluate the associations of obsessive and harmonious passion with psychological and behavioral aspects of ecstasy consumption, we recruited a community sample of ecstasy users to complete a modified version of the Passion Scale (Vallerand et al. 2003) and other questionnaires assessing their substance use history, self-efficacy to refuse ecstasy, and use of ecstasy to cope with worries and problems. Both Obsessive and Harmonious passion scores were negatively correlated with self-efficacy to refuse ecstasy and positively correlated with using ecstasy to cope with worries and problems. The findings also provided partial support for our hypotheses that scores on the Obsessive Passion subscale would be associated with number of times participants had used ecstasy, the frequency of use, and the typical number of pills consumed. Participants agreed more strongly with statements indicative of Harmonious Passion to consume ecstasy, but Harmonious subscale scores were not associated with several measures of consumption. As a supplemental measure, the modified questionnaire could provide a more comprehensive picture of the psychology of one's ecstasy use.

The implications of sleep disruption for cognitive and affective processing in methamphetamine abuse

Sleep is disrupted during active use of methamphetamine (MA), during withdrawal from the drug, and during abstinence from its use. However, relatively little is known about possible mediatory functions of disrupted sleep in the emergence, manifestation, and maintenance of cognitive and affective symptoms of MA abuse. We hypothesise that sleep functions as a mediator for stimulant drug effects. Specifically, we propose that objectively-measured sleep parameters can be used to explain some of the variability in the experience and presentation of memory deficits and emotion dysregulation in MA abusers. After describing how important healthy sleep is to unimpaired cognitive and affective functioning, we review literature describing how sleep is disrupted in MA abuse. Then, we provide a conceptual framework for our hypothesis by explaining the relationship between MA abuse, sleep disruption, memory deficits, emotion dysregulation, and changes in reward-related brain networks. We conclude by discussing implications of the hypothesis for research and treatment.

Why all stimulant drugs are damaging to recreational users: an empirical overview and psychobiological explanation

AIMS

Stimulant drugs such as nicotine and Ecstasy/3, 4-methylenedioxymethamphetamine (MDMA) are taken for positive reasons, yet their regular use leads to deficits rather than gains. This article outlines the psychobiological rationale for this paradox.

METHODS

The empirical literature on nicotine, cocaine, amphetamine, Ecstasy/MDMA, and mephedrone are reviewed. A theoretical explanation for why they are problematic to humans is then described.

RESULTS

The acute effects of central nervous system (CNS) stimulants are typically positive, with greater alertness and emotional intensity. However, in the post-drug recovery period, the opposite feelings develop, with lethargy and low moods. All recreational stimulants cause mood fluctuation, although it is most pronounced in drugs with rapid onset and comedown (e.g. nicotine and cocaine), explaining why they are the most addictive. Parallel fluctuations occur across many psychological and neurocognitive functions, with users suffering various off-drug deficits. CNS stimulants also affect the hypothalamic-pituitary-adrenal axis, impairing sleep, disrupting homeostasis, and exacerbating psychiatric distress. Neuroimaging studies reveal altered brain activity patterns in regular users. These problems are related to lifetime usage but commence in novice users.

CONCLUSIONS

Repetitive CNS stimulation is potentially damaging to the organism, both acutely and chronically. The review describes the various psychobiological systems through which recreational stimulant drugs impair human well-being.

Intimate insight: MDMA changes how people talk about significant others

RATIONALE

±3,4-methylenedioxymethamphetamine (MDMA) is widely believed to increase sociability. The drug alters speech production and fluency, and may influence speech content. Here, we investigated the effect of MDMA on speech content, which may reveal how this drug affects social interactions.

METHOD

Thirty-five healthy volunteers with prior MDMA experience completed this two-session, within-subjects, double-blind study during which they received 1.5 mg/kg oral MDMA and placebo. Participants completed a five-minute standardized talking task during which they discussed a close personal relationship (e.g. a friend or family member) with a research assistant. The conversations were analyzed for selected content categories (e.g. words pertaining to affect, social interaction, and cognition), using both a standard dictionary method (Pennebaker's Linguistic Inquiry and Word Count: LIWC) and a machine learning method using random forest classifiers.

RESULTS

Both analytic methods revealed that MDMA altered speech content relative to placebo. Using LIWC scores, the drug increased use of social and sexual words, consistent with reports that MDMA increases willingness to disclose. Using the machine learning algorithm, we found that MDMA increased use of social words and words relating to both positive and negative emotions.

CONCLUSIONS

These findings are consistent with reports that MDMA acutely alters speech content, specifically increasing emotional and social content during a brief semistructured dyadic interaction. Studying effects of psychoactive drugs on speech content may offer new insights into drug effects on mental states, and on emotional and psychosocial interaction.

Prosocial effects of MDMA: A measure of generosity

BACKGROUND

3,4-methylenedioxymethamphetamine (MDMA) produces "prosocial" effects that contribute to its recreational use. Few studies have examined the cognitive and behavioral mechanisms by which MDMA produces these effects. Here we examined the effect of MDMA on a specific prosocial effect, i.e. generosity, using a task in which participants make decisions about whether they or another person will receive money (Welfare Trade-Off Task; WTT).

METHODS

The project included one study without drug administration and one with MDMA. In Study 1, we administered the WTT to healthy adults (N = 361) and examined their performance in relation to measures of personality and socioeconomic status. In Study 2, healthy volunteers with MDMA experience (N = 32) completed the WTT after MDMA administration (0, 0.5, or 1.0 mg/kg).

RESULTS

As expected, in both studies participants were more generous with a close friend than an acquaintance or stranger. In Study 1, WTT generosity was related to household income and trait Agreeableness. In Study 2, MDMA (1.0 mg/kg) increased generosity toward a friend but not a stranger, whereas MDMA (0.5 mg/kg) slightly increased generosity toward a stranger, especially among female participants.

CONCLUSIONS

These data indicate that the WTT is a valuable, novel tool to assess a component of prosocial behavior, i.e. generosity to others. The findings support growing evidence that MDMA produces prosocial effects, but, as with oxytocin, these appear to depend on the social proximity of the relationships. The brain mechanisms underlying the construct of generosity, or the effects of MDMA on this measure, remain to be determined.

MDMA: a social drug in a social context

RATIONALE

The drug ±3,4-methylenedioxymethamphetamine (MDMA, "ecstasy," "molly") is thought to produce prosocial effects and enhance social interaction. However, in most laboratory studies to date, the participants have been tested under nonsocial conditions, which may not simulate the effects the drug produces in more naturalistic social settings.

METHODS

Healthy experienced MDMA users participated in three laboratory sessions in which they received MDMA (0.5 or 1.0 mg/kg or placebo, double blind). They were randomly assigned to one of three social conditions, in which they were tested alone (solitary (SOL); N = 10), in the presence of a research assistant (research assistant present (RAP); N = 11) or in the presence of another participant who also received the drug (other participant present (OPP); N = 11).

RESULTS

As expected, MDMA increased heart rate and blood pressure and produced positive subjective effects in all the three groups. It also increased ratings of attractiveness of another person and increased social interaction in RAP and OPP. The social context affected certain responses to the drug. The effects of MDMA were greater in the OPP condition, compared to the SOL or RAP conditions, on measures of "feel drug," "dizzy," and on cardiovascular. But responses to the drug on other measures, including social behavior, did not differ across the conditions.

CONCLUSIONS

These findings provide some support for the idea that drugs produce greater effects when they are used in the presence of other drug users. However, the influence of the social context was modest, and it remains to be determined whether other variables related to social context would substantially alter the effects of MDMA or other drugs.

Methamphetamine-induced short-term increase and long-term decrease in spatial working memory affects protein Kinase M zeta (PKMζ), dopamine, and glutamate receptors

Methamphetamine (MA) is a toxic, addictive drug shown to modulate learning and memory, yet the neural mechanisms are not fully understood. We investigated the effects of 2 weekly injections of MA (30 mg/kg) on working memory using the radial 8-arm maze (RAM) across 5 weeks in adolescent-age mice. MA-treated mice show a significant improvement in working memory performance 1 week following the first MA injection compared to saline-injected controls. Following 5 weeks of MA abstinence mice were re-trained on a reference and working memory version of the RAM to assess cognitive flexibility. MA-treated mice show significantly more working memory errors without effects on reference memory performance. The hippocampus and dorsal striatum were assessed for expression of glutamate receptors subunits, GluA2 and GluN2B; dopamine markers, dopamine 1 receptor (D1), dopamine transporter (DAT) and tyrosine hydroxylase (TH); and memory markers, protein kinase M zeta (PKMζ) and protein kinase C zeta (PKCζ). Within the hippocampus, PKMζ and GluA2 are both significantly reduced after MA supporting the poor memory performance. Additionally, a significant increase in GluN2B and decrease in D1 identifies dysregulated synaptic function. In the striatum, MA treatment increased cytosolic DAT and TH levels associated with dopamine hyperfunction. MA treatment significantly reduced GluN2B while increasing both PKMζ and PKCζ within the striatum. We discuss the potential role of PKMζ/PKCζ in modulating dopamine and glutamate receptors after MA treatment. These results identify potential underlying mechanisms for working memory deficits induced by MA.

Effects of MDMA on body temperature in humans

Hyperthermia is a severe complication associated with the recreational use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy). In this review, the clinical laboratory studies that tested the effects of MDMA on body temperature are summarized. The mechanisms that underlie the hyperthermic effects of MDMA in humans and treatment of severe hyperthermia are presented. The data show that MDMA produces an acute and dose-dependent rise in core body temperature in healthy subjects. The increase in body temperature is in the range of 0.2-0.8°C and does not result in hyperpyrexia (>40°C) in a controlled laboratory setting. However, moderately hyperthermic body temperatures >38.0°C occur frequently at higher doses, even in the absence of physical activity and at room temperature. MDMA primarily releases serotonin and norepinephrine. Mechanistic clinical studies indicate that the MDMA-induced elevations in body temperature in humans partially depend on the MDMA-induced release of norepinephrine and involve enhanced metabolic heat generation and cutaneous vasoconstriction, resulting in impaired heat dissipation. The mediating role of serotonin is unclear. The management of sympathomimetic toxicity and associated hyperthermia mainly includes sedation with benzodiazepines and intravenous fluid replacement. Severe hyperthermia should primarily be treated with additional cooling and mechanical ventilation.

MDMA effects consistent across laboratories

RATIONALE

Several laboratories have conducted placebo-controlled drug challenge studies with 3,4-methylenedioxymethamphetamine (MDMA), providing a unique source of data to examine the reliability of the acute effects of the drug across subject samples and settings. We examined the subjective and physiological responses to the drug across three different laboratories and investigated the influence of prior MDMA use.

METHODS

Overall, 220 healthy volunteers with varying levels of previous MDMA experience participated in laboratory-based studies in which they received placebo or MDMA orally (1.5 mg/kg or 125-mg fixed dose) under double-blind conditions. Cardiovascular and subjective effects were assessed before and repeatedly after drug administration. The studies were conducted independently by investigators in Basel, San Francisco, and Chicago.

RESULTS

Despite methodological differences between the studies and differences in the subjects' drug use histories, MDMA produced very similar cardiovascular and subjective effects across the sites. The participants' prior use of MDMA was inversely related to feeling "Any Drug Effect" only at sites testing more experienced users.

CONCLUSIONS

These data indicate that the pharmacological effects of MDMA are robust and highly reproducible across settings. There was also modest evidence for tolerance to the effects of MDMA in regular users.

Plasma oxytocin concentrations following MDMA or intranasal oxytocin in humans

MDMA (±3,4-methylenedioxymethamphetamine, 'ecstasy') is reportedly used recreationally because it increases feelings of sociability and interpersonal closeness. Prior work suggests that the pro-social effects of MDMA may be mediated by release of oxytocin. A direct examination of plasma levels of oxytocin after acute doses of oxytocin and MDMA, in the same individuals, would provide further evidence for the idea that MDMA produces its pro-social effects by increasing oxytocin. Fourteen healthy MDMA users participated in a 4-session, double-blind study in which they received oral MDMA (0.75 and 1.5mg/kg), intranasal oxytocin (20IU or 40IU), and placebo. Plasma oxytocin concentrations, as well as cardiovascular and subjective effects were assessed before and at several time points after drug administration. MDMA (1.5mg/kg only) increased plasma oxytocin levels to a mean peak of 83.7pg/ml at approximately 90-120min, compared to 18.6pg/ml after placebo. Intranasal oxytocin (40IU, but not 20IU) increased plasma oxytocin levels to 48.0pg/ml, 30-60min after nasal spray administration. MDMA dose-dependently increased heart rate, blood pressure, feelings of euphoria (e.g., 'High' and 'Like Drug'), and feelings of sociability, whereas oxytocin had no cardiovascular or subjective effects. The subjective and cardiovascular responses to MDMA were not related to plasma oxytocin levels, although the N was small for this analysis. Future studies examining the effects of oxytocin antagonists on responses to MDMA will help to determine the mechanism by which MDMA produces pro-social effects.

Differential substitution for the discriminative stimulus effects of 3,4-methylenedioxymethamphetamine and methylphenidate in rats

Previous studies have demonstrated that methylphenidate, MDMA (3,4-methylenedioxymethamphetamine), and other psychostimulants exert stimulant-like subjective effects in humans. Furthermore, MDMA and methylphenidate substitute for the discriminative stimulus effects of psychostimulants, such as amphetamine and cocaine, in animals, which suggests that MDMA and methylphenidate may produce similar discriminative stimulus effects in rats. However, there is no evidence regarding the similarities between the discriminative stimulus effects of MDMA and methylphenidate. To explore this issue, cross-substitution, substitution, and combination tests were conducted in rats that had been trained to discriminate between MDMA (2.5 mg/kg) or methylphenidate (5.0 mg/kg) and saline. In the cross-substitution tests, MDMA and methylphenidate did not cross-substitute for each other. In the substitution test, methamphetamine substituted for the discriminative stimulus effects of methylphenidate, but not for those of MDMA. Furthermore, ephedrine and bupropion, which activate dopaminergic and noradrenergic systems, substituted for the discriminative stimulus effects of methylphenidate. On the other hand, serotonin (5-HT) receptor agonists 5-HT1A and 5-HT2 fully substituted for the discriminative stimulus effects of MDMA. These results suggest that activation of the noradrenergic and dopaminergic systems is important for the discriminative stimulus effects of methylphenidate, whereas activation of the serotonergic system is crucial for the discriminative stimulus effects of MDMA. Even though MDMA, like psychostimulants, exerts stimulant-like effects, our findings clearly indicate that the discriminative stimulus effects of MDMA are distinctly different from those of other psychostimulants in rats.

Repeated Acquisition in the Morris Swim Task: Effects of MDMA, Methamphetamine and Methylphenidate

Acute effects of methylenedioxymethamphetamine (MDMA), methamphetamine (MA) and methylphenidate (MPD) were studied using a within-subject, repeated acquisition/performance procedure adapted to the Morris Swim Task. To investigate place learning, the acquisition component consisted of a hidden platform that varied in location across experimental sessions. As a control for drug effects not specific to acquisition, a performance component was included in which the hidden platform was in the same pool location in every experimental session. All three drugs increased escape latencies and swim distances in dose-dependent fashion. However, impairment in the acquisition component was generally observed only at doses that also produced impairment in the performance component, suggesting that effects were not selective to place learning. None of the drugs produced enhancement of learning or performance at any dose. Taken together, the results suggest that acute exposure to these psychomotor stimulants produce global impairment of performance in the Morris task, rather than specific deficits in place learning.

'Ecstasy' as a social drug: MDMA preferentially affects responses to emotional stimuli with social content

3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive 'prosocial' effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content. We hypothesized that MDMA would dose-dependently increase reactivity to positive emotional stimuli and dampen reactivity to negative stimuli, and that these effects would be most pronounced for pictures with people in them. The data were obtained from two studies using similar designs with healthy occasional MDMA users (total N = 101). During each session, participants received MDMA (0, 0.75 and 1.5 mg/kg oral), and then rated their positive and negative responses to standardized positive, negative and neutral pictures with and without social content. MDMA increased positive ratings of positive social pictures, but reduced positive ratings of non-social positive pictures. We speculate this 'socially selective' effect contributes to the prosocial effects of MDMA by increasing the comparative value of social contact and closeness with others. This effect may also contribute to its attractiveness to recreational users.

MDMA is certainly damaging after 25 years of empirical research: a reply and refutation of Doblin et al. (2014)

Human Psychopharmacology recently published my review into the increase in empirical knowledge about the human psychobiology of MDMA over the past 25 years (Parrott, 2013a). Deficits have been demonstrated in retrospective memory, prospective memory, higher cognition, complex visual processing, sleep architecture, sleep apnoea, pain, neurohormonal activity, and psychiatric status. Neuroimaging studies have shown serotonergic deficits, which are associated with lifetime Ecstasy/MDMA usage, and degree of neurocognitive impairment. Basic psychological skills remain intact. Ecstasy/MDMA use by pregnant mothers leads to psychomotor impairments in the children. Hence, the damaging effects of Ecstasy/MDMA were far more widespread than was realized a few years ago. In their critique of my review, Doblin et al. (2014) argued that my review contained misstatements, omitted contrary findings, and recited dated misconceptions. In this reply, I have answered all the points they raised. I have been able to refute each of their criticisms by citing the relevant empirical data, since many of their points were based on inaccurate summaries of the actual research findings. Doblin and colleagues are proponents of the use of MDMA for drug-assisted psychotherapy, and their strongest criticisms were focused on my concerns about this proposal. However, again all the issues I raised were based on sound empirical evidence or theoretical understanding. Indeed I would recommend potentially far safer co-drugs such as D-cycloserine or oxytocin. In summary, MDMA can induce a wide range of neuropsychobiological changes, many of which are damaging to humans.

Increased cortisol levels in hair of recent Ecstasy/MDMA users

Previous research has revealed an acute 8-fold increase in salivary cortisol following self-administrated Ecstasy/MDMA in dance clubbers. It is currently not known to what extent repeated usage impacts upon activity of the hypothalamic-pituitary-adrenal axis over a more prolonged period of time. This study investigated the integrated cortisol levels in 3-month hair samples from recent Ecstasy/MDMA users and non-user controls. One hundred and one unpaid participants (53 males, 48 females; mean age 21.75 years) completed the University of East London recreational drug use questionnaire, modified to cover the past 3-months of usage. They comprised 32 light recent Ecstasy/MDMA users (1-4 times in last 3 months), 23 recent heavy MDMA users (+5 times in last 3 months), and 54 non-user controls. Volunteers provided 3 cm hair samples for cortisol analysis. Hair cortisol levels were observed to be significantly higher in recent heavy MDMA users (mean = 55.0 ± 80.1 pg/mg), compared to recent light MDMA users (19.4 ± 16.0 pg/mg; p=0.015), and to non-users (13.8 ± 6.1 pg/mg; p<0.001). Hence the regular use of Ecstasy/MDMA was associated with almost 4-fold raised hair cortisol levels, in comparison with non-user controls. The present results are consistent with the bio-energetic stress model for Ecstasy/MDMA, which predicts that repeated stimulant drug use may increase cortisol production acutely, and result in greater deposits of the hormone in hair. These data may also help explain the neurocognitive, psychiatric, and other psychobiological problems of some abstinent users. Future study design and directions for research concerning the psychoneuroendocrinological impact of MDMA are also discussed.

Psychiatric profiles of mothers who take Ecstasy/MDMA during pregnancy: reduced depression 1 year after giving birth and quitting Ecstasy

BACKGROUND

The recreational drug MDMA (3,4-methylenedioxymethamphetamine) or 'Ecstasy' is associated with heightened psychiatric distress and feelings of depression. The Drugs and Infancy Study (DAISY) monitored the psychiatric symptom profiles of mothers who used Ecstasy/MDMA while pregnant, and followed them over the first year post-partum.

METHODS

We compared 28 young women whom took MDMA during their pregnancy with a polydrug control group of 68 women who took other psychoactive drugs while pregnant. The Brief Symptom Inventory (BSI) was completed for several periods: The first trimester of pregnancy; and 1, 4 and 12 months after childbirth. Recreational drug use was monitored at each time point.

RESULTS

During the first trimester of pregnancy, MDMA-using mothers reported higher depression scores than the polydrug controls. At 1 year after childbirth, their BSI depression scores were significantly lower, now closer to the control group values. At the same time point, their self-reported use of MDMA became nearly zero, in contrast to their continued use of Cannabis/marijuana, nicotine and alcohol. We found significant symptom reductions in those with BSI obsessive-compulsive and interpersonal sensitivity, following Ecstasy/MDMA cessation.

CONCLUSIONS

The findings from this unique prospective study of young recreational drug-using mothers are consistent with previous reports of improved psychiatric health after quitting MDMA.

MDMA and heightened cortisol: a neurohormonal perspective on the pregnancy outcomes of mothers used 'Ecstasy' during pregnancy

OBJECTIVE

The illicit recreational drug 3,4-methylenedioxymethamphetamine (MDMA) or Ecstasy has strong neurohormonal effects. When taken by recreational users at dance clubs and raves, it can generate an 800% increase in the stress hormone cortisol, whereas drug-free users show chronically raised levels of cortisol. The aim here is to critically debate this neurohormonal influence for the children of pregnant MDMA-using mothers.

METHODS

High levels of cortisol are known to be damaging for neuropsychobiological well-being in adult humans. MDMA can damage foetal development in laboratory animals, and the prospective Drugs and Infancy Study was established to monitor the effects of MDMA taken recreationally by pregnant women.

RESULTS

The Drugs and Infancy Study revealed that young mothers, who took MDMA during the first trimester of pregnancy, gave birth to babies with significant gross psychomotor retardation. These mothers would have experienced high levels of cortisol due to Ecstasy/MDMA use, and since cortisol can cross the placenta, this is likely to have also occurred in the foetus.

CONCLUSIONS

In terms of causation, the developmental problems may reflect a combination of neurotransmitter and neurohormonal effects on the hypothalamic-pituitary-adrenal axis, with serotonergic activity being influenced by the high levels of cortisol.

Efficacy of psychostimulant drugs for amphetamine abuse or dependence

BACKGROUND

Amphetamine dependence is a public health problem with medical, psychiatric, cognitive, legal and socioeconomic consequences. To date, no pharmacological treatment has been approved for this disorder, and psychotherapy remains the mainstay of treatment. In recent years, psychostimulants have been investigated as a possible replacement therapy.

OBJECTIVES

To evaluate the efficacy and safety of psychostimulant medications for amphetamine abuse or dependence. The influences of type of drug, type of dependence, comorbid disorders, clinical trial risk of bias and publication of data were also studied.

SEARCH METHODS

Relevant trials were searched in the following sources: PubMed (January 1966 to 6 June 2012), EMBASE (January 1988 to 6 June 2012), CENTRAL (The Cochrane Library, Issue 5 of 12, May 2012), PsycINFO (January 1985 to 6 June 2012) and the Specialised Register of the Cochrane Drug and Alcohol Group (June 2012). We also searched the reference lists of retrieved trials, the list of studies citing the included trials and the main electronic registers of ongoing trials (ClinicalTrials.gov, International Clinical Trials Registry Platform and EU Clinical Trials Register). Finally, we contacted investigators to request information about unpublished trials. Searches included non-English language literature.

SELECTION CRITERIA

All randomised, placebo-controlled, parallel-group clinical trials investigating the efficacy or safety of psychostimulants for amphetamine dependence or abuse conducted in an outpatient setting.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Eleven studies were included in the review (791 participants). Studied psychostimulants included dexamphetamine, bupropion, methylphenidate and modafinil. No significant differences were found between psychostimulants and placebo for any of the studied efficacy outcomes. Overall retention in studies was low (50.4%). Psychostimulants did not reduce amphetamine use (mean difference (MD) -0.26, 95% confidence interval (CI) -0.85 to 0.33) or amphetamine craving (MD 0.07, 95% CI -0.44 to 0.59) and did not increase sustained abstinence (relative risk (RR) 1.12, 95% CI 0.84 to 1.49). The proportion of adverse events inducing dropout was similar for psychostimulants and placebo (risk difference (RD) 0.01, 95% CI -0.03 to 0.04). The main findings did not change in any subgroup analysis.

AUTHORS' CONCLUSIONS

Results of this review do not support the use of psychostimulant medications at the tested doses as a replacement therapy for amphetamine abuse or dependence. Future research could change this conclusion, as the numbers of included studies and participants are limited and information on relevant outcomes, such as efficacy according to the severity of dependence or craving, is still missing.

Substituted cathinone products: a new trend in "bath salts" and other designer stimulant drug use

There is a growing concern about the availability of a new generation of "designer drug" stimulants that are marketed as "bath salts" and other household products. The products are not true bath salts and contain substituted cathinone stimulant substances, such as methylenedioxypyrovalerone (MDPV) and mephedrone. Calls to the American Association of Poison Control Centers regarding "bath salts" consumption began in 2010 and have continued since that time. Few reports of systematic epidemiologic surveillance or definitive clinical effects of toxicity specifically associated with "bath salts" consumption have been reported in the medical literature. The current narrative review describes the growing trend of designer substituted cathinone use, pharmacology, clinical effects, and recent regulatory changes. It is hoped that a greater understanding of the clinical effects and use patterns will help inform policy and practice.

Human psychobiology of MDMA or 'Ecstasy': an overview of 25 years of empirical research

AIMS

This paper aimed to review how scientific knowledge about the human psychobiology of MDMA has developed over time.

METHODS

In this paper, the empirical findings from earlier and later studies will be reviewed.

RESULTS

When MDMA was a 'novel psychoactive substance', it was not seen as a drug of abuse, as it displayed loss of efficacy. However, recreational users display a unique pattern of increasing doses, deteriorating cost-benefit ratios, and voluntary cessation. MDMA increases body temperature and thermal stress, with cortisol levels increased by 800% in dance clubbers. It can be extremely euphoric, although negative moods are also intensified. MDMA causes apoptosis (programmed cell death) and has been investigated for cancer therapy because of its anti-lymphoma properties. Recreational users show deficits in retrospective memory, prospective memory, higher cognition, problem solving, and social intelligence. Basic cognitive skills remain intact. Neuroimaging studies show reduced serotonin transporter levels across the cerebral cortex, which are associated with neurocognitive impairments. Deficits also occur in sleep architecture, sleep apnoea, complex vision, pain, neurohormones, and psychiatric status. Ecstasy/MDMA use during pregnancy leads to psychomotor impairments in the children.

CONCLUSIONS

The damaging effects of Ecstasy/MDMA are far more widespread than was realized a few years ago, with new neuropsychobiological deficits still emerging.

Substitutional potential of mephedrone: an analysis of the subjective effects

OBJECTIVE

In the past 25-30 years, a large number of synthetic and non-synthetic drugs have appeared on the recreational scene, but with the exception of 4-methylmethcathinone (mephedrone), none of these substances reached the popularity of ecstasy [3,4-methylenedioxy-N-methylamphetamine, (MDMA)]. Authors aimed to determine the subjective effects of mephedrone in order to understand how mephedrone can serve as a potential substitute for entactogens, such as MDMA.

METHODS

One hundred forty-five mephedrone users--recruited by snowball method--filled out a questionnaire on their patterns of use and experienced subjective effects of mephedrone.

RESULTS

Factor analysis revealed six factors of mephedrone-induced subjective effects: positive emotions, sensibility, adverse somatic effects, adverse psychological effects, stimulant effects, and psychedelic effects. A preference list of subjective effects indicates that mephedrone is popular primarily for its psychostimulant and entactogen effects. Latent class analysis identified two classes of mephedrone users, with closely parallel profiles. The two classes differed in severity of subjective experience in a way that was consistent across the six dimensions.

CONCLUSIONS

By having similar subjective effects as MDMA and other entactogens, mephedrone seems able to substitute other enactogenic stimulants.

Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study

We report follow-up data evaluating the long-term outcomes for the first completed trial of 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for chronic, treatment-resistant post-traumatic stress disorder (PTSD) (Mithoefer et al., 2011). All of the 19 subjects who received MDMA-assisted treatment in the original trial participated in the long-term follow-up (LTFU), with 16 out of 19 completing all of the long-term outcome measures, which were administered from 17 to 74 months after the original study's final MDMA session (mean = 45.4; SD = 17.3). Our primary outcome measure used was the Clinician-Administered PTSD Scale (CAPS). Secondary outcome measures were the Impact of Events Scale-Revised (IES-R) and the Neuroticism Extroversion Oppenness Personality Inventory-Revised (NEO PI-R) Personality Inventory. We also collected a long-term follow-up questionnaire. Results for the 16 CAPS completers showed there were no statistical differences between mean CAPS score at LTFU (mean = 23.7; SD = 22.8) (t (matched) = 0.1; df = 15, p = 0.91) and the mean CAPS score previously obtained at Study Exit (mean = 24.6, SD = 18.6). On average, subjects maintained statistically and clinically-significant gains in symptom relief, although two of these subjects did relapse. It was promising that we found the majority of these subjects with previously severe PTSD who were unresponsive to existing treatments had symptomatic relief provided by MDMA-assisted psychotherapy that persisted over time, with no subjects reporting harm from participation in the study.

Contrasting effects of d-methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxypyrovalerone, and 4-methylmethcathinone on wheel activity in rats

BACKGROUND

Reports from U.S., U.K. and European drug policy entities, and ongoing media accounts, show increasing recreational use of 4-methylmethcathinone (4-MMC, mephedrone) and 3,4-methylenedioxypyrovalerone (MDPV). Severe sympathomimetic symptoms, hallucinations, psychoses, and even deaths have been reported, yet little scientific information is available on the effects of these compounds in laboratory models. Available studies on the neurochemistry of these drugs show that 4-MMC and MDPV enhance DA neurotransmission, while 4-MMC additionally enhances 5-HT neurotransmission--a pattern much like that reported for methamphetamine versus 3,4-methylenedioxymethamphetamine (MDMA). As is the case for designer amphetamines, these neurochemical distinctions may predict differential potential for repetitive versus episodic abuse and distinct lasting toxicities.

METHODS

This study determined relative locomotor stimulant effects of 4-MMC (1-10 mg/kg, s.c.) and MDPV (0.5-5.6 mg/kg, s.c.), in comparison with d-methamphetamine (MA; 0.5-5.6 mg/kg, s.c.) and MDMA (1-7.5 mg/kg, s.c.) on a measure of locomotor activity--voluntary wheel running--in male Wistar rats (N=8).

RESULTS

Compared to counts of wheel rotations after saline, a biphasic change in the pattern of counts was observed after injections of MA and MDPV, with relatively higher counts following lower doses and lower counts following the highest dose. However, monophasic, dose-dependent reductions in counts were observed in response to injections of MDMA and 4-MMC.

CONCLUSION

Thus, voluntary wheel running yielded the same categorical distinctions for these drugs as did prior experiments testing the effects of these drugs on monoaminergic neurotransmission. These data indicate that MDPV produces prototypical locomotor stimulant effects whereas 4-MMC is more similar to the entactogen MDMA.

Mephedrone (4-methylmethcathinone) and d-methamphetamine improve visuospatial associative memory, but not spatial working memory, in rhesus macaques

BACKGROUND AND PURPOSE

The novel cathinone derivative 4-methylmethcathinone (4-MMC; mephedrone) is increasingly popular with recreational users. Little scientific information is available but users report both entactogen-like and classic stimulant-like subjective properties. A recent study in humans reported psychomotor speed improvement after intranasal 4-MMC suggesting classic stimulant properties. Limitations of the user group (which was impaired on some tasks) prompt controlled laboratory investigation.

EXPERIMENTAL APPROACH

Adult male rhesus monkeys were trained to perform tasks from the non-human primate Cambridge Neuropsychological Test Automated Battery, which assess spatial working memory, visuospatial associative memory, learning and motivation for food reward. Test of bimanual motor coordination and manual tracking were also included. The subjects were challenged with 0.178-0.56 mg·kg(-1) 4-MMC and 0.056-0.56 mg·kg(-1) d-methamphetamine (MA), i.m., in randomized order for behavioural evaluation.

KEY RESULTS

A pronounced improvement in visuospatial memory and learning was observed after the 0.32 mg·kg(-1) dose of each compound, this effect was confirmed with subsequent repetition of these conditions. Spatial working memory was not improved by either drug, and the progressive ratio, bimanual motor and rotating turntable tasks were all disrupted in a dose-dependent manner.

CONCLUSIONS AND IMPLICATIONS

These studies show that 4-MMC produces behavioural effects, including improvements in complex spatial memory and learning that are in large part similar to those of MA in non-human primates. Thus, the data suggest that the effects of 4-MMC in monkeys can be classified with classical psychomotor stimulants.

Is cognitive functioning impaired in methamphetamine users? A critical review

The prevailing view is that recreational methamphetamine use causes a broad range of severe cognitive deficits, despite the fact that concerns have been raised about interpretations drawn from the published literature. This article addresses an important gap in our knowledge by providing a critical review of findings from recent research investigating the impact of recreational methamphetamine use on human cognition. Included in the discussion are findings from studies that have assessed the acute and long-term effects of methamphetamine on several domains of cognition, including visuospatial perception, attention, inhibition, working memory, long-term memory, and learning. In addition, relevant neuroimaging data are reviewed in an effort to better understand neural mechanisms underlying methamphetamine-related effects on cognitive functioning. In general, the data on acute effects show that methamphetamine improves cognitive performance in selected domains, that is, visuospatial perception, attention, and inhibition. Regarding long-term effects on cognitive performance and brain-imaging measures, statistically significant differences between methamphetamine users and control participants have been observed on a minority of measures. More importantly, however, the clinical significance of these findings may be limited because cognitive functioning overwhelmingly falls within the normal range when compared against normative data. In spite of these observations, there seems to be a propensity to interpret any cognitive and/or brain difference(s) as a clinically significant abnormality. The implications of this situation are multiple, with consequences for scientific research, substance-abuse treatment, and public policy.