National Amphetamine-Type Stimulant Strategy Background Paper: Monograph Series No. 69
3.1 Effects for users
The action of amphetamine-type stimulants in the brain elevates levels of the monoamine neurotransmitters dopamine, serotonin (5-HT) and noradrenaline (Rothman & Baumann, 2003). Dopamine is involved in the regulation of movement; cognitive processes related to attention, working memory and motivational behaviour; and is the primary neurotransmitter involved in reward pathways (Tzschentke, 2001). Serotonin has a role in a variety of physiological processes, and in complex behaviours such as mood, appetite, sleep, cognition, perception, motor activity, temperature regulation, pain control, sexual behaviour and hormone secretion (Kema et al., 2000). Noradrenaline is responsible for mediating cardiovascular effects, arousal, concentration, attention, learning and memory (Ressler & Nemeroff, 1999).
As noted, ATS include both meth/amphetamine and MDMA or ecstasy. The difference between these groups of drugs is that MDMA primarily inhibits serotonin reuptake and stimulates serotonin release, while methamphetamine has the same effects on dopamine (Clemens et al., 2007; Dean 2004). The differential release of neurotransmitters by MDMA and methamphetamine results in relatively unique subjective effects produced by each drug. While MDMA is more likely to produce euphoria, mild hallucinations and feelings of closeness to others, methamphetamine is more likely to enhance confidence, energy and sexual stimulation (Clemens et al., 2007; Dean 2004).
The effects of ATS include the sought after effects, and negative short-term and long term consequences. Both the intended and the adverse consequences will depend on the amount taken, purity, physiological factors such as age and general health, individual tolerance to the drug and the context in which the intoxicating effects are experienced. The sought after effects of meth/amphetamine include a sense of wellbeing, euphoria, mood elevation, increased libido, alertness, reduced fatigue, increased concentration, diminished appetite, enhanced reflexes, and a perceived increase in confidence, energy, and physical strength (AIDS Council of New South Wales (ACON), 2006; Dean, 2004). At relatively low doses, performance of simple motor and cognitive tasks can improve (although performance may deteriorate after larger doses or after regular use) (e.g., Brauer & de Wit, 1997; Rogers et al., 1999). The immediate sought after effects of ecstasy are similar and include a subjective sense of closeness to other people, enhanced sociability, positive mood states, including a sense of wellbeing and euphoria, and changed perceptions, in particular sharpened sensory perception (AIDS Council of New South Wales (ACON), 2006; Dean 2004; Tancer & Johanson, 2001). For ecstasy, the balance of positive to negative effects shifts after a relatively short period of repeated use, possibly acting as a disincentive to frequent use (e.g., Peroutka et al., 1988).
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As with the sought after effects, the adverse effects of ATS are dose and frequency related (i.e., their likelihood and intensity increase with increasing dose and increasing use). The short-term adverse effects of meth/amphetamine include: restlessness, irritation, anxiety, agitation, tremor, teeth grinding, insomnia, confusion, increased heart rate and irregular heart beat, abdominal pain, sweating, dilated pupils, fatigue, and parasitosis (picking and scratching skin) (ACON, 2006; Dean 2004). The short-term adverse effects of ecstasy include racing thoughts, depersonalisation, panic attacks, tremor, muscle cramps, increased heart rate, decreased capacity to cope with changing ambient temperature (which may result in hypo- or hyperthermia), hyperactivity, insomnia and impairment of sexual functioning (Cohen 1998; Dean 2004; Peroutka et al., 1988).
The sought after effects and adverse effects were discussed during consultations. In addition to ‘rush’ or euphoric experiences, it was noted that ATS are sometimes used to enhance sexual performance and for weight loss. It was also noted that some people might use ATS as self-medication to alleviate distress and anxiety. However, these latter symptoms may in fact become exacerbated following use and during ‘come down’, which can then result in further use and instigate a binge-crash cycle. It was noted that following 2 to 5 days after abstinence many regular users would experience a lack of energy and enthusiasm, reduced concentration, poor motivation, irritability and possibly anger. Longterm effects mentioned by participants in the consultations included poor diet and nutrition, kidney and heart problems, and high stress levels.
