Psychostimulants are a group of drugs including amphetamines, cocaine and ecstasy (MDMA). The term “amphetamine” includes the three types of amphetamines: amphetamine, dexamphetamine and methamphetamine. Most illicit drugs bought in Australia as speed or amphetamines are likely to be methamphetamine.

Ice is the strongest form of methamphetamine. It is the highest purity form of methamphetamine and is usually smoked or injected.

In general, stimulants make you feel good they increase dopamine production in the brain that promotes alertness, confidence and a sense of wellbeing. Dopamine is a neurotransmitter in our brains that is responsible for reinforcing pleasurable activities that are good for our survival so we repeat them. Stimulants hijack this reward system and fool the brain into thinking the drug use is good for survival but unfortunately this is not the case. Individuals who become addicted to stimulants have moved into a pattern of repeated use and require higher doses, in an increasing search for intense euphoric sensations.


Amphetamine psychosis

High doses and frequent heavy use can also create an ‘amphetamine psychosis’, characterised by paranoid delusions, hallucinations and out of character aggressive or violent behaviour. These symptoms usually disappear a few days after the person stops using amphetamines.

Effects of higher doses


  • Headaches
  • Pale skin
  • Restlessness
  • Dizziness
  • Rapid or irregular heartbeat
  • Paranoia
  • Anxiety
  • Panic attacks
  • Depression
  • Confusion (feeling “scattered”)
  • Psychosis



Immediate effects of stimulants


  • Increased alertness
  • Increased energy
  • Increased confidence
  • Euphoria
  • Increased talkativeness
  • Loss of appetite
  • Insomnia
  • Increased heart rate and breathing
  • Nausea/vomiting
  • Headaches
  • Jaw clenching and teeth grinding
  • Hot and cold flushes
  • Sweats




















Withdrawal from stimulants will be different for different people.

The intensity of the symptoms experienced can depend on a few things such as how much you were using, your general health, any existing mental health issues and the length of time you have been using.

Stimulant withdrawal typically occurs in three phases.


1. The crash phase

Commences as the effects of stimulants wear off, and can last for several days.  Amphetamine crash typically commences 12–24 hours after last amphetamine use, and subsides by days 2–4. Cocaine crash occurs within hours of last use, with short duration (up to 48 hours). Some individuals do not report a significant crash on stopping cocaine.

Cocaine crash occurs within hours of last use, with short duration (up to 48 hours). Some individuals do not report a significant crash on stopping cocaine.

Common signs and symptoms:

  • Exhaustion and fatigue
  • Sleep disturbances (typically increased sleep, although insomnia or restless sleep may occur)
  • Mood disturbances — typically flat mood or dysphoria; may be associated with anxiety or agitation
  • Low cravings
  • Generalised aches and pains

 2. The withdrawal phase

Amphetamine withdrawal typically commences 2–4 days after last amphetamine use and peaks in severity over 7–10 days, and then subsides over 2–4 weeks.

Cocaine withdrawal typically commences 1–2 days after last use, peaking in severity over 4–7 days and then subsides over 1–2 weeks.

Withdrawal features of stimulant use are predominantly psychological, with fluctuating mood and energy levels, cravings, disturbed sleep, and poor concentration. Withdrawal features gradually subside during the extinction phase.

 Common signs and symptoms:

  • Strong cravings
  • Fluctuating mood and energy levels, alternating between: Irritability,
  • restlessness, anxiety, and agitation
  • Fatigue, lacking energy, anhedonia
  • Disturbed sleep, including vivid dreams, insomnia
  • General aches and pains, headaches
  • Muscle tension
  • Increased appetite
  • Poor concentration and attention
  • Disturbances of thought (eg, paranoid ideation, strange beliefs) and perception (misperceptions, hallucinations) can re-emerge during withdrawal phase after having been masked during crash.

 3. The extinction phase

 Typically lasts from weeks to months.

 Common signs and symptoms:

  • Gradual resumption of normal mood with episodic fluctuations in mood and energy levels, alternating between: irritability, restlessness, anxiety, agitation, fatigue, lacking energy and anhedonia
  • Episodic cravings
  • Disturbed sleep

Withdrawal from stimulant drugs is not medically dangerous, and no specific treatment has been shown to be effective. The usual objectives in treating stimulant withdrawal are to assist you to interrupt a period or pattern of compulsive use, to identify and manage any comorbid conditions and to commence relapse prevention treatment.