Drugs which are distinguished by their capability of diminishing or suspending unpleasant perceptions or emotions, with little effect on conciousness. They induce a state of mental comfort. According to Restak:

"Thanks to euphoriants, the difficulties and frustrations of the present can be replaced by substitute worlds of the mind’s own creation, words in which problems disappear, anxieties are quieted, and desires are sated".

Lewin included in this group opium and its derivatives as well as cocaine. The last mentioned agent, in Restak’s opinion, would today be taken out of this group by most psychopharmacologists, and included in the excitants group.

Also called "drugs of illusion", they induce sensory and perceptive alterations such as hallucinations and illusions (mainly visual). An example is mescaline, extracted from the peyote cactus (scientific name Anhalonium lewinii). In this group we can also include LSD, harmine (present in ayahuasca, intoxicant used by South American Indians and extracted from two plants – B. caapi and B. Inebrians), hashish and the anticholinergic alkaloids hyoscyamine, atropine and scopolamine.

These drugs produce behavioral excitement as well as perceptual, cognitive, and affective alterations. This group includes ether, chloroform, ethyl chloride, and the drug most used at all places and times, alcohol.

Substances used to induce sleep, like barbiturates and, modernly, some types of benzodiazepines.

Drugs which produce cerebral excitation and behavioral stimulation without altering consciousness. This group includes caffeine, amphetamines and, according to present standards, cocaine.

Alcohol abuse without dependence

9,4%

Alcohol dependence

14,1%

Drug-abuse without dependence

4,4%

Drug dependence

7,5%