Numerous evidences suggest that fear could be implicated in the negative emotional state induced by withdrawal from drugs of abuse and in the development of diverse psycopathologies. The main purpose of the present study was to evaluate the potential facilitation of fear reaction employing a contextual conditioning fear paradigm in diazepam withdrawn animals. Adult male Wistar rats were subjected to a chronic diazepam treatment (2 mg/kg/day, i.p.) during 21 days. When the withdrawal-induced anxiogenic behavior was not longer evident (day 4 of withdrawal), diazepam withdrawn rats were exposed to 5 footshocks (0,7 mA; 3s duration). The freezing response, as a behavioral expression of fear, was evaluated 24 h after the shock session in the context previously paired with these aversive stimuli. This response was also evaluated in a novel unpaired context as a behavioral output of unconditioned fear learning. Diazepam withdrawn rats showed an enhanced contextual fear response expressed as an enhanced freezing behavior. Furthermore, this enhanced fear reaction induced by prior exposure to inescapable footshock was also evident on day 12 and 18 of diazepam withdrawal. These exaggerated emotional reactions which persist until day 18 of abstinence may indicate that diazepam withdrawal alters the ability to modulate emotional responses induced by subsequent aversive situations.
