Contribution of Caffeine to the Psychostimulant, Neuroinflammatory and Neurotoxic Effects of Amphetamine-Related Drugs

Does early exposure to caffeine promote smoking and alcohol use behavior? A prospective analysis of middle school students

BACKGROUND AND AIMS

Despite the negative consequences associated with caffeine use among children and youth, its use is increasingly widespread among middle school students. Cross-sectional studies reveal links between caffeine and other substance use. The potential for caffeine use to confer increased vulnerability to substance use, however, has not been investigated using prospective designs. We hypothesized that caffeine use at baseline would be associated positively with increased alcohol use, drunkenness, smoking and e-cigarette use.

DESIGN

Prospective cohort study with 12 months separating baseline from follow-up.

SETTING

West Virginia, USA.

PARTICIPANTS

Middle school students (6th and 7th grades; n = 3932) in three West Virginia (WV) counties provided data at baseline and follow-up 12 months later.

MEASUREMENTS

Youth self-reported their use of caffeine from multiple sources (e.g. soda, energy drinks, coffee and tea), cigarette smoking, electronic cigarette use, alcohol use and drunkenness.

FINDINGS

Cross-lagged path models for individual substance use categories provided a good fit to the data. Controlling for demographic variables and other substance use at baseline, caffeine at time 1 (T1) was associated positively with T2 cigarette smoking (β = 0.27, P = 0.001), e-cigarette use (β = 0.21, P = 0.001), alcohol use (β = 0.17, P = 0.001) and drunkenness (β = 0.15, P = 0.001). Conversely, non-significant relations emerged between three of four substances at T1 and caffeine at T2. Positive relations were found between e-cigarette use at T1 and caffeine use at T2 (β = 0.07, P = 0.006). These findings were supported by an omnibus model with all substances included. Specifically, significant relations were observed between caffeine at T1 and all substance use outcomes at T2, whereas no significant relations were observed between substance use and caffeine over time.

CONCLUSIONS

Caffeine may promote early use of other types of substances among middle school-aged adolescents.

Amphetamine-related drugs neurotoxicity in humans and in experimental animals: Main mechanisms

Amphetamine-related drugs, such as 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine (METH), are popular recreational psychostimulants. Several preclinical studies have demonstrated that, besides having the potential for abuse, amphetamine-related drugs may also elicit neurotoxic and neuroinflammatory effects. The neurotoxic potentials of MDMA and METH to dopaminergic and serotonergic neurons have been clearly demonstrated in both rodents and non-human primates. This review summarizes the species-specific cellular and molecular mechanisms involved in MDMA and METH-mediated neurotoxic and neuroinflammatory effects, along with the most important behavioral changes elicited by these substances in experimental animals and humans. Emphasis is placed on the neuropsychological and neurological consequences associated with the neuronal damage. Moreover, we point out the gap in our knowledge and the need for developing appropriate therapeutic strategies to manage the neurological problems associated with amphetamine-related drug abuse.

Co-ingestion of energy drinks with alcohol and other substances among a sample of people who regularly use ecstasy

INTRODUCTION AND AIMS

Despite the potential harms of mixing unregulated drugs with energy drinks (ED), research to date has primarily been focused on EDs co-ingested with alcohol. Consequently, the aim of the present study was to explore the rate of use, harms and correlates of EDs co-ingested with alcohol and other drugs among a sample of people who regularly use illicit stimulant drugs.

DESIGN AND METHODS

In 2010, 693 Australians who regularly used ecstasy completed a 1-h interview about their past six-month ED and drug use.

RESULTS

Three-quarters of the sample (77%) had recently consumed EDs with other substances, primarily alcohol (70%) and ecstasy (57%). People who consumed ED with alcohol versus those who had consumed ED with ecstasy and with alcohol (only 8% reported only consuming ED with ecstasy) had similar profiles in regards to demographics, drug use, mental health and drug-related problems. Primary motives for consuming ED with alcohol included increased alertness (59%), the taste (25%), to party for longer (23%) and to combat fatigue (16%). One-half (52%) and one-quarter (27%) of participants who consumed EDs with alcohol and with ecstasy respectively had recently experienced adverse outcomes post-consumption, primarily headaches (24% and 11%) and heart palpitations (21% and 14%).

DISCUSSION AND CONCLUSIONS

Co-ingestion of EDs with licit and illicit drugs is common among people who regularly use ecstasy and related drugs. Adverse outcomes of co-ingestion suggest that targeted education regarding negative interactive drug effects is crucial for harm reduction. [Peacock A, Sindicich N, Dunn M, Whittaker E, Sutherland R, Entwistle G, Burns L, Bruno R. Co-Ingestion of Energy Drinks with Alcohol and Other Substances among a Sample of People Who Regularly Use Ecstasy. Drug Alcohol Rev 2016;35:352-358].