IntroductionImpulsiveness is one of the main features of a series of psychiatric entities such as ADHD, gambling addiction, disorders related to psychoactive substance use, impulse control disorders such as pyromania and certain personality disorders such as antisocial and borderline personality disorder.According to Moeller et al., impulsiveness can be defined as a predisposition towards rapid, unplanned reactions to internal and external stimuli regardless of the negative consequences of these reactions [1]. In accordance with the latest studies, there is a tendency to describe impulsiveness as a mul dimensional construct within which the behavioural impulsiveness is described as the impossibility of stopping the initiated reaction or action and cognitive impulsiveness as the impossibility to form an adequate judgement on the consequences of somebody's behaviour. These two dimensions of impulsiveness are described as independent and different phenomena. It can be assumed that in the future these constructs will be additionally developed and complemented [2]. Conceptual definitions of impulsiveness often state the following dimensions: lack of perseverance, sensation seeking, i.e. new contents, lack of premeditation before acting, urgency and increased sensitivity to gratification [3].Impulsiveness is also often described as a part of personality traits and so do Patton et al. distinguish between the motoric aspect of impulsiveness related to action without premeditation and cognitive aspect related to urgent decision-making, non-planning, which is described as focusing on the present and having difficulties to maintain attention [4]. Impulsiveness can be quantified in two ways - by self-reports and neuropsychological tests which use specific movements with the aim to evaluate various components of impulsiveness such as the time thinking was initiated, i.e. making slow or fast decisions in situations of high insecurity. Delaying gratification and fast response are two clear ways a person can operationalize impulsiveness [5,6].A large number of conducted studies showed that addicts had scored generally higher on the impulsiveness scale of selfevaluation scales than persons not diagnosed with an addiction, i.e. not consuming psychoactive substances and that impulsiveness was one of the most important factors for developing and maintaining addiction [7,8]. This was also supported by the fact that the very diagnostic criteria for diagnosing an addiction syndrome also overlapped to a large extent with the elements of the impulsiveness definition. The previous research studies showed that impulsiveness plays an important role in the clinical course, i.e. it represents an important predictive factor for the occurrence of relapse and significantly affects the response to treatment of both addicts on psychoactive substances, such as alcohol addicts, and gambling addicts, as the only recognised behavioural addicts [9,10].With psychoactive substance addictions, as with behavioural addictions, impulsiveness can be observed as the determining factor or the vital causative factor for the development of an addiction, but also as a consequence of psychoactive substance addictions. As a determinant or one of the causative factors, impulsive personality traits represent a risk factor for beginning to experiment with psychoactive substances, developing addiction and making abstinence more difficult once the addiction is developed and the change of the impulsiveness intensity is in direct correlation to the amount of the psychoactive substance consumption [11]. However, psychoactive substances per se can have an impact on impulsiveness, an acute one, i.e. due to their primary effect, but also as a longterm consequence of psychoactive substance consumption. The acute effect of alcohol, as well of other psychoactive substances, results in a reduction of inhibition, i.e. a change of the decision-making process, thus raising the probability of engaging in all forms of risk behaviour. …