Chronic drug abuse, stress reactivity
and vulnerability to relapse
Most commonly abused drugs such as alcohol, nicotine,
cocaine, amphetamines, opiates and marijuana that stimulate
brain reward pathways (mesocorticolimbic dopaminergic
systems) also activate brain stress systems (Cobb
and Van Thiel 1982; Cinciripini et al. 1989; Robinson
and Berridge 1993; Baumann et al. 1995; Heesch et al.
1995; Kreek and Koob 1998). As stated earlier, activation
of brain stress circuits increases dopaminergic neurotransmission
in brain reward pathways (Thierry et al.
1976; Dunn 1988; Kalivas and Duffy 1989; Prasad et al.
1995; Piazza and Le Moal 1996; Goeders 1997). Given
that the neural circuitry in brain stress and reward pathways
overlap considerably, this section examines whether
neuroadaptations in these circuits increases the vulnerability
to stress and relapse to drugs.