Behavioural modifications induced by psychotropic drugs result primari
ly from their pharmacological properties. According to classification
of psychotropic drugs, sedative compounds contrast with psychostimulat
ing medications. Behavioural effects of psychotropic drugs depend art
dosing, subject's status (patient or healthy, volunteer), acute or chr
onic administration, and environment. Some psychotropic compounds, par
ticularly sedative drugs, decrease the level of mental alertness and c
ognitive functioning. But those deleterious effects tend to disappear
during the course of a repeated administration. Some psychotropic drug
s, especially benzodiazepines, induce a tolerance effect, eventually a
psychic or a physiological dependence state evidenced by withdrawal r
eactions Such similar dependence processes have been reported with oth
er psychotropic drugs Forensic problems have been attributed to some p
sychotropic compounds like benzodiazepines: paradoxical agressive reac
tions, psychomotor automatism ; Psychotropic drugs usually can confer
a positive effect on behaviour owing to their therapeutic action by th
e way of improving the illness and consequently the life of patients i
n the cases of depression, anxiety or schizophrenia.