Drugs and bugs: Negative affect, psychostimulant use and withdrawal, and the microbiome.

Background And Objectives: A growing body of literature demonstrates that the human microbiota plays a crucial role in health and disease states, as well as in the body's response to stress. In addition, the microbiome plays a role in psychological well-being and regulating negative affect. Regulation of negative affect is a factor in psychostimulant abuse disorders. We propose a risk chain in which stress leads to negative affect that places an individual at risk to develop or relapse to psychostimulant abuse disorder. Stress, negative affect, and psychostimulant use all alter the gut microbiome.

Methods: This review brings together the literature on affective disorders, stress, and psychostimulant abuse disorders to assess possible modulatory actions of the gut-brain axis to regulate these conditions.

Results: Studies reviewed across the various disciplines suggest that the dysbiosis resulting from drug use, drug withdrawal, or stress may cause an individual to be more susceptible to addiction and relapse. Probiotics and prebiotics reduce stress and negative affect.

Scientific Significance: Treatment during the withdrawal phase of psychostimulant abuse disorder, when the microbiome is altered, may ameliorate the symptoms of stress and negative affect leading to a reduced risk of relapse to psychostimulant use.