“…This 1-month duration is unusual compared to the 1-to 7-day effect seen in rats withdrawn from chronic amphetamine (eg Leith and Barrett, 1976;Kokkinidis and Zacharko, 1980;Kokkinidis et al, 1986;Lin et al, 1999;Paterson et al, 2000), cocaine Koob, 1991, 1992a;Baldo et al, 1999), opiates (Schulteis et al, 1994), ethanol (Schulteis et al, 1995), and nicotine (Epping-Jordan et al, 1998;Harrison et al, 2001). Further, attempts to increase the duration of the effect of amphetamine and nicotine withdrawal on reward threshold using repeated withdrawal from continuous administration of these drugs were not successful (Paterson et al, 2000;Skjei and Markou, 2003). Interestingly, when nicotine was given for a prolonged period of time (ie 28 vs 7 days via subcutaneous osmotic minipumps), rats exhibited a 14-15 day elevation in brain reward threshold during the subsequent withdrawal that was independent of the dose administered (Skjei and Markou, 2003).…”