Please note: Dosage equivalents are provided for certain drugs below and are denoted as unit equivalents, i.e. one unit of drug x is roughly the equivalent as one unit of drug y, where the dosage equal to one unit varies.
A chemical medicinal formulation, Amphetamines are stimulant medications that increase awareness, attention and focus. They are primarily used to combat ADHD and narcolepsy but can also be used to fight weight gain and depression; they sadly have a great capacity for abuse and is most commonly known as speed.
Dextroamphetamine (Dexamphetamine)
Working on the monoamine neurotransmitters dopamine and noradrenaline, Dextroamphetamine is a powerful stimulant used to treat illnesses such as ADHD; it was first synthesised in 1887. It can also be used to treat narcolepsy where non-medical treatment has proven ineffective and in cases of severe depression and weight loss where obesity is grossly rampant.
However, this drug has the capacity to be easily abused as get-up-and-go pep pills or as a main means to combat weight gain with; as such, Dextroamphetamine should not be prescribed in cases where there is a history of substance abuse or self medication.
Interestingly, the USA Air Force uses this drug as an alertness pill for personnel on long term missions; it has been similarly used by NASA.
In overdose, this drug can precipitate psychosis and a "doll like" state with diluted pupils and a fixed face, along with hyperactivity and insomnia.
Dextroamphetamine & Laevoamphetamine
Used to treat ADHD and narcolepsy, this drug can also be used to treat severe depression and - extremely rarely - obesity. It was for the latter use for which this drug was first prescribed in the 1970s.
The manufacturer claims that the mix of the two salts helps soften the effects without losing any potency when compared to the other stimulants, although there is little evidence to support this.
The drug messes with the monoamine neurotransmitters dopamine and noradrenaline, increasing the amount of said chemicals available to neurons to soak in.
Common side effects include rises in ones heart rate, insomnia, anorexia, vertigo, headaches and irritability.
Methamphetamine
This drug is one of the primary drugs prescribed to treat traumatic brain injury and narcoleptic disorders and is prescribed to treat depression and ADHD. IT was first registered and patented in 1954; it is infamous as a treatment in the USA as it is by far the most prescribed medication for ADHD and one that has been notably abused by certain individuals.
Interestingly, whilst Methamphetamine is a stimulant, it has a calming effect on patients with ADHD.