to amphetamines should be viewed as a stressor in the acute phase for the vulnerable individual in a dynamic way; for individuals with lower vulnerability higher doses of amphetamines are needed, whereas individuals with higher vulnerability require lower doses to precipitate acute psychosis. In addition, due to their sensitizing effects, amphetamines may also play a role in the devel- opment of vulnerability. Repeated use of amphetamines could increase vulnerability, thereby increasing the chances of developing psychotic symptoms even in the absence of (acute exposure to) amphetamines. Thus, primary psychotic disorder and psychosis precipitated by amphetamines need not be considered as two separ- ate phenomena, but as two phenomena interlinked in a dynamic way.