Sex differences in addiction

Figures & data

Figure 1. Figure 1. Females are more likely to develop a preference for cocaine. (A) The development of cocaine preferences in male (open circles) and female (filled circles) rats (n =12 per sex). Significant increase in the proportion of cocaine-preferring (CP) females between the second and last fixed-ratio 5 (FR5) tests (*P=0.05). The proportion of CP females was greater than males ($P=0.05). (B) The stability of preferences in pellet-preferring (PP) rats and CP rats (both before and after CP developed). Significant difference between PP and CP rats within same preference category (#P=0.05). Significant difference in preference category before and after CP developed (*P=0.05). Significant difference between the “preference for cocaine” and “preference for pellets” categories within a given group (^P=0.05). PP rats (n = 16) and CP rats (n = 8). (C) Representative self-administration behavior in a PP rat over the 21 FR sessions, displaying the number of infusions (gray) and pellets (black) earned each day during the cocaine-only or pellet-only sessions (closed symbols) and the choice session (open symbols). (D) Representative self-administration behavior in a CP rat (CP criteria met on day 11 in this case). Reproduced from ref 44: Perry AN, Westenbroek C, Becker JB. The development of a preference for cocaine over food identifies individual rats with addiction-like behaviors. PLoS ONE. 2013;8(11):e79465. Reproduced under the Creative Commons Attribution License.

Figure 2. A sagittal section of the rat brain depicting some of the neural systems involved in the reward system. Not shown are the glutamate projections from frontal cortex and other brain regions, as well as the GABAergic neurons and the enkaphalin and dynorphin neurons in the nucleus accumbens and dorsal striatum. BST, bed nucleus of the stria terminalis; CeA, central nucleus of the amygdala; DS, dorsal striatum; Fcx, frontal cortex; LC, locus coeruleus; NAc, nucleus accumbens; NTS, nucleus tractus solitarus; VTA/SN, ventral tegmental area/substantia nigra. Reproduced from ref 8: Becker JB, Perry AN, Westenbroek C. Sex differences in the neural mechanisms mediating addiction: a new synthesis and hypothesis. Biol Sex Differ. 2012;3(1):14. Reproduced under the Creative Commons Attribution License. Copyright © 2012, Becker et al, licensee BioMed Central Ltd.