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

Chemical similarity of molecules with physiological response

Measuring the similarity among molecules is an important task in various chemically oriented problems. This elusive concept is hard to define and quantify. Moreover, the complexity of the problem is elevated by bifurcating the notion of molecular similarity to structural and chemical similarity. While the structural similarity of molecules is being extensively researched, the so-called chemical similarity is being mentioned scarcely. Here, we propose a way of converting the physico-chemical properties into molecular fingerprints. Then, using the apparatus of measuring the structural similarity, the chemical similarity can be assessed. The proof of a concept is demonstrated on a set of molecules that induce diverse physiological responses.

Examining Symptoms of Stimulant Misuse and Community Support Among Members of a Recovery-Oriented Online Community

Misuse of prescription and non-prescription stimulants and related overdose deaths represent a growing public health crisis that warrants immediate intervention. We examined 100 posts and their respective comments from a public, recovery-oriented Reddit community in January 2021 to explore content related to DSM-V stimulant use disorder symptoms, access and barriers to recovery, and peer support. Using inductive and deductive methods, a codebook was developed with the following primary themes: 1) DSM-V Symptoms and Risk Factors, 2) Stigma/Shame, 3) Seeking Advice or Information, 4) Supportive or Unsupportive Comments. In 37% of posts community members reported taking high doses and engaging in prolonged misuse of stimulants. Nearly half of posts in the sample (46%) were seeking advice for recovery, but 42% noted fear of withdrawal symptoms or a loss of productivity (18%) as barriers to abstinence or a reduction in use. Concerns related to stigma, shame, hiding use from others (30%), and comorbid mental health conditions (34%) were also noted. Social media content analysis allows for insight into information about lived experiences of individuals struggling with substance use disorders. Future online interventions should address recovery barriers related to stigma and shame as well as fears associated with the physical and psychological impact of quitting stimulant misuse.

Cigarettes, heated tobacco products and dual use: exhaled carbon monoxide, saliva cotinine and total tobacco consumed by Hong Kong tobacco users

BACKGROUND

Independent studies on exhaled carbon monoxide (CO) and saliva cotinine levels in regular heated tobacco product (HTP) users, and how they compare with conventional cigarette (CC) smokers, are lacking.

METHODS

A total of 3294 current users of CCs, HTPs or electronic cigarettes (ECs) from a household survey and a smoking hotspot survey were classified into seven groups: exclusive users of CCs, HTPs, ECs; dual users of CCs and HTPs, CCs and ECs, HTPs and ECs; and triple users. We measured exhaled CO level using the piCo Smokerlyzer (n=780) and saliva cotinine using NicAlert cotinine test strips (n=620). Among the seven groups, the differences in (1) CO and cotinine levels were examined using Kruskal-Wallis test, and (2) the average daily tobacco consumption in the past 30 days was examined using multivariable linear regression.

RESULTS

Both exclusive and dual users of CCs had a higher CO level than exclusive HTP or EC users (p<0.05). Exhaled CO levels were similar between HTP and EC users, as were saliva cotinine levels among the seven groups. Compared with exclusive CC users, those who also used HTPs or ECs smoked fewer CCs (CCs+HTPs: adjusted coefficient -2.79, 95% CI -3.90 to -1.69; CCs+ECs: -1.34, 95% CI -2.34 to -0.34), but consumed more tobacco sticks equivalent in total (2.79 (95% CI 1.61 to 3.96); 1.95 (95% CI 0.79 to 3.12)).

CONCLUSIONS

HTP or EC use showed lower exhaled CO but similar saliva cotinine levels compared with CC use. Dual users of CCs and HTPs/ECs smoked fewer CCs than exclusive CC users, but consumed more tobacco in total.

Methamphetamine and sleep impairments: neurobehavioral correlates and molecular mechanisms

Methamphetamine is a potent and highly addictive psychostimulant, and one of the most widely used illicit drugs. Over recent years, its global usage and seizure have been on a rapid rise, with growing detrimental effects on mental and physical health, and devastating psychosocial impact pressing for intervention. Among the unwanted effects of methamphetamine, acute and long-term sleep impairments are of major concern, posing a significant therapeutic challenge, and a cause of addiction relapse. Unraveling mechanisms and functional correlates of methamphetamine-related sleep and circadian disruption are, therefore, of key relevance to translational and clinical psychiatry. In this article, we review the mounting evidence for the acute and long-term impairements of sleep-wake behavior and circadian activity caused by single or recurring methamphetamine usage and withdrawal. Factors contributing to the severity of sleep loss and related cognitive deficit, with risks of relapse are discussed. Key molecular players mediating methamphetamine-induced dopamine release and neuromodulation are considered, with wake-promoting effects in mesolimbic circuits. The effects on various sleep phases and related changes in dopamine levels in selected subcortical structures are reviewed and compared to other psychostimulants with similar action mechanisms. A critical appraisal is presented of the therapeutic use of modafinil, countering sleep, and circadian rhythm impairments. Finally, emerging knowledge gaps and methodical limitations are highlighted along with the areas for future research and therapeutic translation.

Illicit Drug Use and Associated Problems in the Nightlife Scene: A Potential Setting for Prevention

Illicit drug use is prevalent in the nightlife scene, especially at electronic dance music (EDM) events. The aim of the present study was to investigate illicit drug use patterns and consequences of drug use among frequent visitors of EDM events. Young adults (18-34 years old) who had visited at least six EDM events in Sweden during the past year participated in a web-based survey on drug use patterns and its consequences. Fifty-nine percent of participants had used illicit drugs during the past year, most often cannabis followed by ecstasy, cocaine, and amphetamine. Nightlife venues were identified as the main setting for the use of central stimulants, while cannabis was mostly used at home. Frequent alcohol and tobacco use was associated with illicit drug use. The most prevalent negative consequences of drug use were related to mental health, such as impairments in mood, sleep, and memory problems, but physical manifestations were also reported, such as palpitations and collapsing. These findings confirm that drug use is prevalent and associated with negative health effects among EDM nightlife attendees. The nightlife scene is a setting with promising potential to reach a high-risk target group with illicit drug use prevention interventions.

The impact of chronic daily nicotine exposure and its overnight withdrawal on the structure of anxiety-related behaviors in rats: Role of the lateral habenula

Tobacco smoking is a serious health problem worldwide and a leading cause of mortality. Nicotine, the addictive component of tobacco, affects a range of emotional responses, including anxiety-related behaviors. Although perceived by smokers to be anxiolytic, evidence suggests that smoking increases anxiety and that mood fluctuates with nicotine intake. Thus, nicotine addiction may depend on easing the psychobiological distress caused by its abuse. The lateral habenula (LHb) has been implicated as a neural substrate for acute nicotine-induced anxiety, but its role in anxiety-like behaviors associated with chronic nicotine exposure has not been explored. Here, we assessed the effect of chronic nicotine exposure and its subsequent overnight withdrawal on anxiety-like behavior using both quantitative and multivariate T-pattern analysis in rats tested using the hole-board apparatus. Additionally, we explored the role of the LHb by comparing the behavioral effects of short-term nicotine withdrawal in chronically treated LHb-lesioned rats. Quantitative analysis revealed increased anxiety-like behavior in chronically treated overnight nicotine-deprived rats, as manifested in reduced general and focused exploratory behaviors, which was eased in animals that received nicotine. Quantitative analysis failed to reveal a role of the LHb in overnight nicotine deprivation-induced anxiety. Conversely, T-pattern analysis of behavioral outcomes revealed that chronic nicotine-treated rats still show anxiety-like behavior following nicotine challenge. Moreover, it demonstrated that the LHb lesion induced a stronger anxiolytic-like response to the acute challenge of nicotine in chronically nicotine-exposed animals, implicating the LHb in the anxiogenic effect of chronic nicotine exposure. These data further highlight the LHb as a promising target for smoking cessation therapies and support the importance of T-pattern analysis for behavioral analysis.

A prospective longitudinal study shows putamen volume is associated with moderate amphetamine use and resultant cognitive impairments

Background

Amphetamine-type stimulants (ATS) have become a critical public health issue. Animal models have indicated a clear neurotoxic potential of ATSs. In humans, chronic use has been associated with cognitive deficits and structural brain abnormalities. However, cross-sectional retrospective designs in chronic users cannot truly determine the causal direction of the effects.

Objective

To prospectively determine effects of occasional ATS use on cognitive functioning and brain structure.

Methods

In a prospective longitudinal study design, cognitive functioning and brain structure were assessed at baseline and at 12-month follow-up in occasional ATS users (cumulative lifetime use <10 units at baseline).

Results

Examination of change scores between the initial examination and follow-up revealed declined verbal memory performance and putamen volume in users with high relative to low interim ATS exposure. In the entire sample, interim ATS use, memory decline, and putamen volume reductions were strongly associated.

Conclusions

The present findings support the hypothesis that ATS use is associated with deficient dorsal striatal morphology that might reflect alterations in dopaminergic pathways. More importantly, these findings strongly suggest that even occasional, low-dose ATS use disrupts striatal integrity and cognitive functioning.

Lack of longitudinal changes in cognition in individuals with methamphetamine use disorder during the first 6 weeks after commencing treatment

Background: Methamphetamine use disorder (MUD) associates with cognitive impulsivity deficits. However, few studies have examined longitudinal changes in cognition, and it remains unclear if deficits resolve during early recovery.Objectives: To compare: (1) cognitive function of individuals with MUD at treatment onset and six-weeks later with controls tested over the same period; (2) cognitive changes in MUD-individuals who remained abstinent versus relapsed.Method: We recruited 108 participants meeting DSM-IV-TR criteria for methamphetamine dependence (81 males) and 50 demographically matched controls (38 males); 77 methamphetamine- dependent participants (59 males) and 48 controls (36 males) were retained at follow-up. We administered response inhibition, delay discounting and uncertainty-based decision-making tests at both endpoints. Relapse was defined as methamphetamine concentrations >0.4 ng/mg at follow-up in hair toxicology.Results: We found a significant time-by-group interaction on uncertainty-based decision-making (effect size: η² = .05), although post-hoc tests to disentangle this interaction yielded inconclusive results (p-range = .14-.40; BF₁₀-range = 0.43-1.67). There were no significant time-by-group interactions on response inhibition or delay discounting, with the former likely a null effect (η²-interaction = .003 and .02; BF_incl = 0.23 and 0.71). There were no significant differences in cognitive recovery between individuals who maintained abstinence (n = 12) versus relapsed (n = 65) (η²-range = .003-.04), although evidence was inconclusive toward whether findings reflected true null effects (BF_incl-range = 0.33-0.75).Conclusion: We did not find evidence that MUD-related cognitive impulsivity deficits improve beyond practice effects over 6 weeks. Findings do not support previous, albeit conflicting, evidence of early recovery of cognitive deficits in MUD.

Self-reported PTSD is associated with increased use of MDMA in adolescents with substance use disorders

BACKGROUND

Adolescent patients with a substance use disorder (SUD) often fulfil the criteria for a co-occurring post-traumatic stress disorder (PTSD). However, it is not clear if these dual-diagnosed adolescents present with unique levels of substance use and how their substance use relates to PTSD symptom clusters.

OBJECTIVE

To investigate substance use in adolescents with co-occurring PTSD and SUD. Additionally, we explored how the use of specific substances is related to specific PTSD symptom clusters.

METHOD

We recruited n = 121 German adolescent SUD patients, in three groups: no history of traumatic events (TEs) (n = 35), TEs but not PTSD (n = 48), probable PTSD (n = 38). All groups were administered a trauma questionnaire and were asked to report their past-month substance use.

RESULTS

Adolescents with probable PTSD and SUD report a higher frequency of MDMA use than adolescents with no PTSD and no TE (PTSD vs. noTE: U = 510.5, p = .016; PTSD vs. TE: U = 710.0, p = .010). The use of MDMA was more frequent in adolescents with avoidance symptoms (X² (1) = 6.0, p = .014). Participants report using substances at a younger age (PTSD vs. noTE: U = 372.0, p = .001; PTSD vs. TE: U = 653.5, p = .022) and PTSD symptom onset was on average 2.2 years earlier than first MDMA use (t (26) = -2.89, p = .008).

CONCLUSIONS

Adolescent SUD patients with probable PTSD are more likely to use MDMA than SUD patients without PTSD. The use of MDMA was associated with reported avoidance symptoms. The first age of MDMA use is initiated after PTSD onset. It is unclear whether the association of MDMA use with avoidance symptoms is due to efforts to reduce these symptoms or a result of regular MDMA use.

Mephedrone and MDMA: A comparative review

Mephedrone and MDMA are both constituents of party drugs, with mephedrone being relatively new compared to MDMA. This review compares current knowledge regarding the patterns of usage and neuropsychobiological effects of both mephedrone and MDMA. Both drugs share common psychoactive effects, the duration of which is significantly shorter with mephedrone use, attributing towards a pattern of binge use among users. Both drugs have also been associated with adverse health, psychiatric, and neurocognitive problems. Whilst there is extensive research into the psychobiological problems induced by MDMA, the evidence for mephedrone is comparatively limited. The adverse effect profile of mephedrone appears to be less severe than that of MDMA. Users often believe it to be safer, although both drugs have been associated with overdoses. The neurotoxic potential of mephedrone appears to be low, whereas MDMA can cause long-term damage to the serotonergic system, although this needs further investigation. The abuse liability of mephedrone is significantly greater than that of MDMA, raising concerns regarding the impact of lifetime usage on users. Given that mephedrone is relatively new, the effects of long-term exposure are yet to be documented. Future research focused on lifetime users may highlight more severe neuropsychobiological effects from the drug.

Of mice and men on MDMA: A translational comparison of the neuropsychobiological effects of 3,4-methylenedioxymethamphetamine ('Ecstasy')

MDMA (3,4-methylendioxymethamphetamine), also known as Ecstasy, is a stimulant drug recreationally used by young adults usually in dance clubs and raves. Acute MDMA administration increases serotonin, dopamine and noradrenaline by reversing the action of the monoamine transporters. In this work, we review the studies carried out over the last 30 years on the neuropsychobiological effects of MDMA in humans and mice and summarise the current knowledge. The two species differ with respect to the neurochemical consequences of chronic MDMA, since it preferentially induces serotonergic dysfunction in humans and dopaminergic neurotoxicity in mice. However, MDMA alters brain structure and function and induces hormonal, psychomotor, neurocognitive, psychosocial and psychiatric outcomes in both species, as well as physically damaging and teratogen effects. Pharmacological and genetic studies in mice have increased our knowledge of the neurochemical substrate of the multiple effects of MDMA. Future work in this area may contribute to developing pharmacological treatments for MDMA-related disorders.

A fractionated analysis of hot and cool self-regulation in cigarette smokers from different socioeconomic backgrounds

Smoking cigarettes and low socioeconomic status (SES) are both related to impaired cognition. However, it is unknown whether people of lower SES, who comprise most tobacco smokers worldwide, are more susceptible to cognitive impairment associated with smoking. In this non-randomized, cross-sectional study we investigated the effects of cigarette smoking, SES and their interaction on dissociable executive or “cool” and “hot” measures of behavioural self-regulation. Participants (n = 80) were selected among young physically and mentally healthy smokers and non-smokers who had graduated high school and were from different SES backgrounds. Cool self-regulation was measured by executive function tasks that tap inhibition, updating, shifting, dual tasking, planning, access to long-term memory (semantic fluency), and working memory capacity. Hot measures assessed self-reported impulsivity, delay discounting and risk taking. Exposure to tobacco (cotinine, exhaled carbon monoxide, tobacco dependence, cigarette consumption) was assessed to determine to what extent it mediated the cognitive effects of smoking. Nicotine abstinence and its acute effects were controlled, as were sex, age, schooling, and psychiatric symptoms despite the fact that smokers and non-smokers were selected as being as similar as possible in these demographic characteristics. Lower SES (less years of parental schooling) was associated with worse performance on tasks that measured all cool domains except dual tasking and fluency, while smoking status was related to impaired delayed discounting and impulsivity (hot domains), effects that were not mediated by tobacco exposure. Smoking and SES, however, did not interact. In short, impaired performance in measures of most cool skills was associated with SES irrespective of smoking status; in contrast, regardless of SES, smokers showed specific impairment in hot self-regulation domains (more difficulty resisting immediate temptations and weighing future consequences of actions). Possible explanations for the lack of mediation of tobacco exposure on hot skills of smokers are discussed.

Methamphetamine-associated difficulties in cognitive control allocation may normalize after prolonged abstinence

Chronic heavy methamphetamine use likely causes dopaminergic neurotoxicity, which is commonly thought to result in cognitive control deficits. Both of these alterations may persist even after the use is discontinued, but tend to (partly) improve with increasing duration of abstinence. While several studies have demonstrated that the reinstatement of comparatively normal dopaminergic signaling may take months, if not years, the amelioration of cognitive deficits has predominantly been investigated in much shorter intervals of several weeks to less than half a year. Against this background, we set out to investigate the effects on prolonged abstinence in n = 27 abstinent former methamphetamine users in a cross-sectional design using behavioral and neurophysiological measures of cognitive control. Our behavioral results suggest that former users struggled to identify and adapt to different degrees of cognitive control requirements, which made their behavioral performance less expedient than that of healthy controls. On the neurophysiological level, this was reflected by reduced modulations of the N2-N450 amplitude in response to high vs. low cognitive control requirements. Yet, those effects could only be observed in methamphetamine users who had been abstinent for a relatively short time (mean 9.9; max. 18 months), but not in former users who had been abstinent two years or longer. While this finding alone does not allow for causal inferences, it suggests that the amelioration of control deficits may take longer than what is commonly investigated (1-6 months). Hence, some of the statements about permanent/irreversible dopamine-dependent executive dysfunctions in former methamphetamine users should be interpreted with caution.

Evidence of 2 Populations of Mephedrone Abusers by Hair Testing. Application to 4 Forensic Expertises

Background

New psychoactive substances are conquering the drug scene. Among these substances, cathinone derivatives have been observed since late in the years 2000. At that time, there was evidence of increasing use of the synthetic cathinone mephedrone, particularly amongst clubbers. Although the emergent drugs have an aura of safety, there is an increasing amount of experiences on their secondary effects. Mephedrone is known to induce psychosis.

Method

Given the potential negative effects of mephedrone, the laboratory was asked to test for the drug in hair, a cumulative matrix that can document single, occasional or repetitive abuse of xenobiotics. Mephedrone was tested in hair by GC/MS, using a standard procedure developed for stimulants such as amphetamine or ecstasy.

Results

In the head hair of 24 positive abusers, mephedrone was identified in the range 0.1 to 87 ng/mg, clearly determining 2 populations, one with co-administration of ecstasy and a second without ecstasy. In the first population, mephedrone concentrations were 0.1 to 5 ng/mg; in the second population, mephedrone concentrations were 3 to 87 ng/mg. These findings should help in the understanding the addiction of subjects. In 4 separate forensic cases, mephedrone was identified in hair of abusers, including a rape case (0.54 ng/mg), a fatal car crash (0.38 ng/mg), a fatal drowning (1.21 ng/mg), and a fatal overdose (6.99 ng/mg).

Conclusion

Hair testing for new psychoactive substances appears as a good complement to standard urine analyses. This study confirms the increasing diffusion of new drugs among the forensic population of abusers.

Associations of unhappiness with sociodemographic factors and unhealthy behaviours in Chinese adolescents

Background

Evidence on the effects of lack of physical exercise, alcohol drinking and smoking on happiness is limited and inconsistent. We examined the associations of unhappiness with sociodemographic factors and these unhealthy behaviours in Chinese adolescents. In a school-based survey in 2012-13 in Hong Kong, 45 857 secondary school students (mean age 14.8 years, 54.0% boys) reported their happiness level (not happy at all/not very happy/happy/very happy), frequency of physical exercise, alcohol drinking status, smoking status and sociodemographic factors. A main and a sensitivity analysis examined the associations of unhappiness with the study factors, treating unhappiness as a binary (combining 'not happy at all' and 'not very happy') and a four-level ordered variable, respectively. The main and the sensitivity analysis both showed that unhappiness was associated with older age, very poor families, non-intact families, more co-residing smokers, lack of physical exercise and alcohol drinking; current smokers were unhappier than never and ex-smokers; unhappiness also increased significantly with the number of unhealthy behaviours ( P for trend < 0.001). In Chinese adolescents, unhappiness levels were higher in those who had a very poor family, a non-intact family and more co-residing smokers, and in those who were physically inactive, drank alcohol and smoked.

Mood Fluctuation and Psychobiological Instability: The Same Core Functions Are Disrupted by Novel Psychoactive Substances and Established Recreational Drugs

Many novel psychoactive substances (NPS) have entered the recreational drug scene in recent years, yet the problems they cause are similar to those found with established drugs. This article will debate the psychobiological effects of these newer and more traditional substances. It will show how they disrupt the same core psychobiological functions, so damaging well-being in similar ways. Every psychoactive drug causes mood states to fluctuate. Users feel better on-drug, then feel worse off-drug. The strength of these mood fluctuations is closely related to their addiction potential. Cyclical changes can occur with many other core psychobiological functions, such as information processing and psychomotor speed. Hence the list of drug-related impairments can include: homeostatic imbalance, HPA axis disruption, increased stress, altered sleep patterns, neurohormonal changes, modified brain rhythms, neurocognitive impairments, and greater psychiatric vulnerability. Similar patterns of deficit are found with older drugs such as cocaine, nicotine and cannabis, and newer substances such as 3,4-methylenedioxymethamphetamine (MDMA), mephedrone and spice. All psychoactive drugs damage human well-being through similar basic neuropsychobiological mechanisms.

Differential effects of MDMA and cocaine on inhibitory avoidance and object recognition tests in rodents

INTRODUCTION

Drug addiction continues being a major public problem faced by modern societies with different social, health and legal consequences for the consumers. Consumption of psychostimulants, like cocaine or MDMA (known as ecstasy) are highly prevalent and cognitive and memory impairments have been related with the abuse of these drugs.

AIM

The aim of this work was to review the most important data of the literature in the last 10 years about the effects of cocaine and MDMA on inhibitory avoidance and object recognition tests in rodents.

DEVELOPMENT

The object recognition and the inhibitory avoidance tests are popular procedures used to assess different types of memory. We compare the effects of cocaine and MDMA administration in these tests, taking in consideration different factors such as the period of life development of the animals (prenatal, adolescence and adult age), the presence of polydrug consumption or the role of environmental variables. Brain structures involved in the effects of cocaine and MDMA on memory are also described.

CONCLUSIONS

Cocaine and MDMA induced similar impairing effects on the object recognition test during critical periods of lifetime or after abstinence of prolonged consumption in adulthood. Deficits of inhibitory avoidance memory are observed only in adult rodents exposed to MDMA. Psychostimulant abuse is a potential factor to induce memory impairments and could facilitate the development of future neurodegenerative disorders.

Heritability of lifetime ecstasy use

BACKGROUND

Ecstasy is a widely used psychoactive drug that users often take because they experience positive effects such as increased euphoria, sociability, elevated mood, and heightened sensations. Ecstasy use is not harmless and several immediate and long term side effects have been identified. Lifetime ecstasy use is likely to be partly influenced by genetic factors, but no twin study has determined the heritability. Here, we apply a classical twin design to a large sample of twins and siblings to estimate the heritability of lifetime ecstasy use.

METHODS

The sample comprised 8500 twins and siblings aged between 18 and 45 years from 5402 families registered at the Netherlands Twin Registry. In 2013-2014 participants filled out a questionnaire including a question whether they had ever used ecstasy. We used the classical twin design to partition the individual differences in liability to ecstasy use into that due to genetic, shared environmental, and residual components.

RESULTS

Overall, 10.4% of the sample had used ecstasy during their lifetime, with a somewhat higher prevalence in males than females. Twin modelling indicated that individual differences in liability to lifetime ecstasy use are for 74% due to genetic differences between individuals, whereas shared environmental and residual factors explain a small proportion of its liability (5% and 21%, respectively). Although heritability estimates appeared to be higher for females than males, this difference was not significant.

CONCLUSIONS

Lifetime ecstasy use is a highly heritable trait, which indicates that some people are genetically more vulnerable to start using ecstasy than others.

Recreational 3,4-methylenedioxymethamphetamine or 'ecstasy': Current perspective and future research prospects

AIMS

The purpose of this article is to debate current understandings about the psychobiological effects of recreational 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy'), and recommend theoretically-driven topics for future research.

METHODS

Recent empirical findings, especially those from novel topic areas were reviewed. Potential causes for the high variance often found in group findings were also examined.

RESULTS AND CONCLUSIONS

The first empirical reports into psychobiological and psychiatric aspects from the early 1990s concluded that regular users demonstrated some selective psychobiological deficits, for instance worse declarative memory, or heightened depression. More recent research has covered a far wider range of psychobiological functions, and deficits have emerged in aspects of vision, higher cognitive skill, neurohormonal functioning, and foetal developmental outcomes. However, variance levels are often high, indicating that while some recreational users develop problems, others are less affected. Potential reasons for this high variance are debated. An explanatory model based on multi-factorial causation is then proposed.

FUTURE DIRECTIONS

A number of theoretically driven research topics are suggested, in order to empirically investigate the potential causes for these diverse psychobiological deficits. Future neuroimaging studies should study the practical implications of any serotonergic and/or neurohormonal changes, using a wide range of functional measures.

Recreational stimulants, herbal, and spice cannabis: The core psychobiological processes that underlie their damaging effects

AIMS

Recreational drugs are taken for their positive mood effects, yet their regular usage damages well-being. The psychobiological mechanisms underlying these damaging effects will be debated.

METHODS

The empirical literature on recreational cannabinoids and stimulant drugs is reviewed. A theoretical explanation for how they cause similar types of damage is outlined.

RESULTS

All psychoactive drugs cause moods and psychological states to fluctuate. The acute mood gains underlie their recreational usage, while the mood deficits on withdrawal explain their addictiveness. Cyclical mood changes are found with every central nervous system stimulant and also occur with cannabis. These mood state changes provide a surface index for more profound psychobiological fluctuations. Homeostatic balance is altered, with repetitive disturbances of the hypothalamic-pituitary-adrenal axis, and disrupted cortisol-neurohormonal secretions. Hence, these drugs cause increased stress, disturbed sleep, neurocognitive impairments, altered brain activity, and psychiatric vulnerability. Equivalent deficits occur with novel psychoactive stimulants such as mephedrone and artificial "spice" cannabinoids. These psychobiological fluctuations underlie drug dependency and make cessation difficult. Psychobiological stability and homeostatic balance are optimally restored by quitting psychoactive drugs.

CONCLUSIONS

Recreational stimulants such as cocaine or MDMA (3.4-methylenedioxymethamphetamine) and sedative drugs such as cannabis damage human homeostasis and well-being through similar core psychobiological mechanisms.

Mephedrone and 3,4-methylenedioxy-methamphetamine: Comparative psychobiological effects as reported by recreational polydrug users

AIMS

The purpose of this study was to compare the effects of mephedrone and 3,4-methylenedioxy-methamphetamine (MDMA), as reported by young recreational polydrug users.

METHODS

152 MDMA users and 81 mephedrone users were recruited through snowballing on social network sites. They completed a standard online questionnaire for either mephedrone or MDMA. The questions covered the average amount taken per session, the longest duration of usage in the last 12-months, subjective effects while on-drug, and recovery effects in the days afterwards.

RESULTS

Mephedrone users reported a significantly longer maximum session of use than MDMA users. Mephedrone users also reported a significantly greater average amount used per session. The majority of on-drug subjective ratings did not differ between drugs, with similar increases in entactogenic effects. Although mephedrone users did report significantly more frequent issues with sleeping, anger and anxiety. In relation to recovery, mephedrone users reported more frequent craving, nasal irritation, paranoia, and relationship difficulties. Mephedrone users also rated general recovery effects as more severe over the seven-day period following use, taking more days to feel normal.

CONCLUSIONS

The acute effects of MDMA and mephedrone were broadly similar. However, the recovery period for mephedrone was more enduring, possibly due to the longer duration of acute session usage.

Developmental outcomes of 3,4-methylenedioxymethamphetamine (ecstasy)-exposed infants in the UK

OBJECTIVE

This paper aims to review findings from a longitudinal study of prenatal methylenedioxymethamphetamine (MDMA, "ecstasy") on infant development.

METHODS

In a prospective, longitudinal cohort design, we followed 28 MDMA-exposed and 68 non-MDMA-exposed infants from birth to 2 years of age. Women recruited voluntarily into a study of recreational drug use during pregnancy were interviewed to obtain type, frequency, and amount of recreational drug use. Their children were followed for a 2-year period after birth. A large number of drug and environmental covariates were controlled. Infants were seen at 1, 4, 12, 18, and 24 months using standardized normative tests of mental and motor development.

RESULTS

There were no differences between MDMA-exposed and non-MDMA-exposed infants at birth except that MDMA-exposed infants were more likely to be male. Motor delays were evident in MDMA infants at each age and amount of MDMA exposure predicted motor deficits at 12 months in a dose-dependent fashion.

CONCLUSIONS

Prenatal MDMA exposure is related to fine and gross motor delays in the first 2 years of life. Follow-up studies are needed to determine long-term effects.