Risks and Severity

The use of illegal drugs involves many long- and short-term risks. Do not endanger your health: do not use illegal drugs! If, however, you do in fact use illegal drugs, it is advisable to be supported or accompanied by some other person who can call the emergency services in the case of sudden severe illness.

Overview of the main risks

The abuse of drugs involves many risks that can occur acutely after intake or after a longer period. Some of these risks are related to the substance itself while others result from the behaviour adopted during drug abuse:

  • physical risks
  • psychological risks
  • behavioural risks
  • social risks.

It should be noted that some people are more vulnerable than others to the physical and psychological risks:

  • stressed, anxious, depressed people
  • people who already are suffering from psychiatric, psychological and psychic disorders (depression, attention deficit disorders, hyperactivity)
  • persons suffering from cardiovascular diseases, epilepsy, lung diseases, etc.
  • genetic predisposition.

The table below describes the main physical and psychological risks for illegal drugs (X: frequent risk, °: rare risk)

  Stimulants Hallucinogens Tranquilizers
Drugs Coc. Crack Amph. Khat Ecst. LSD  Mushr. Cactus Salvia Ayahua. Canna. Keta. GHB Hero.
Risks
Cardiovascular x x x x x       x x x     x
Psychiatric x x x x x x x x x x x x x x
Neurological x x   x x       x       x  
Infections (HIV, hepatitis) x x x                     x
Obstetrical x x x x x x x x x x x x x x
Physical dependence ° ° °     °             x x
Psychological dependence x x x x ° ° °       x x x x
Risk of overdose x x x   x x x         x x x

Physical risks

Everyone reacts differently to drugs according to their psychological and physical health, environment, and the quality and the quantity of the drug consumed. 

The risks can be directly related to the consumption, occur just after it or appear gradually due to regular abuse over the long term (chronic use).

Immediate risks

  • Dehydration, breathing difficulties, heart disorders
  • Overdose: loss of consciousness which can lead to death, related to the quantity and quality of the used drug, toxic cutting agents or NPS
  • Crash”: unpleasant symptoms which occur once the effect of the drug has worn off (fatigue, tachycardia, insomnia, nervousness, dizziness, etc.)

Long-term risks

  • Insomnia, headaches, dizziness, nausea, loss of memory, cardiac disorders, etc.

DID YOU KNOW? The brain continues to develop in adolescence and it is particularly vulnerable to the toxic effects of alcohol and drugs, even after the age of 18. Drugs can interfere with the normal development of the brain. Regular and prolonged abuse of cannabis, started in adolescence, can cause deterioration in intellectual performance. 

Psychological risks

Drugs act on the central nervous system and, among other things, on the chemical substances present in the brain: neurotransmitters.

Dopamine, serotonin and noradrenaline are the most important neurotransmitters which have an effect on our senses, moods and perceptions. 

Over the long-term, the brain can suffer more or less imbalances which result in psychological problems: dependence, depression, concentration difficulties, anxiousness, sadness, panic attacks, emotional changes, conflicts, stress, etc.

DID YOU KNOW? The abuse of drugs in pregnant women can involve risks for the foetus (miscarriages, effects on intrauterine growth, foetal death in utero, premature birth, underdevelopment of the foetus) and also for the child after birth (below average weight, withdrawal syndrome, respiratory and cardiac disorders). 

At-risk behaviour

The abuse of drugs involves certain indirect risks related to behaviour, such as the way intravenous injecting is carried out or the irresponsible behaviour adopted under the influence of drugs: 

Social risks

The physical and psychological problems of the abuse of drugs can have repercussions on a person’s social life: family conflicts, isolation, loss of interest in one’s own life, violence, financial problems, academic or professional difficulties, criminality, exclusion, marginalisation, delinquency, problems with the law, etc.

Dangerous mixes 

Combining various illicit drugs and/or using illegal drugs together with alcohol, cigarettes and medications can increase the risks, in particular those of respiratory depression (difficulty in breathing and getting oxygen).


Sciensano collects data and analyses the consumption of drugs, the drug market, the consequences for health, requests for treatment and the policies implemented with regard to drugs in Belgium.

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