Psychostimulant addiction, most notably cocaine and amphetamine - type stimulants are an important public health problem
worldwide. It appears that social factors may influence the initiation, maintenance and recovery from addictions. Several animal models
have been developed to study addiction, highlighting drug self-administration (SA) and the conditioned place preference (CPP) paradigms.
These models have been modified to accurately reflect the characteristics of drug addiction in its different stages. One factor that
clearly plays a major role in addiction is stress, which is a risk factor not only for the initiation, maintenance and escalation of drug consumption,
but also for relapse. In animal models, stress for itself can provoke reinstatement of self-administration or CPP. The relationship
between stress and addiction is very tight. One example is the close anatomical relationship of some areas that share these two phenomena.
It seems obvious to think that the main source of stress in humans is social interaction. The aim of the present review is to gather
the current information regarding the role of social stress in the addiction to psychostimulant drugs in animal models. First, we briefly describe
the mechanisms by which stress exerts its effects and the basic concepts of addiction. We will try to establish common pathways of
stress and addiction, to address later social stress effects on different stages of addiction. Then, we will address pharmacological therapies
and preventive factors that counteract the enhancing effects of social stress in addiction. Finally, we will analyze how negative environmental
conditions may induce individuals to increased vulnerability to drugs, and how favorable environmental conditions may have protective
and curative effects against addiction. In this sense, we also analyze the importance of social interactions and their ability to
modulate the different stages of addiction. As a conclusion, and despite the scarcity of the research, social stress exposure increases the
initiation of psychostimulant consumption and the vulnerability to relapse in animal models of addiction. Studies on the mechanisms underlying
the effects of social stress and how it can be counteracted pharmacologically, are research areas that should be explored in the
future. At the same time, translational research on the effects of environmental conditions and positive social interactions, which have
been shown to have a critical role in addictions, should be encouraged.