Co-occurrence of substance use disorders and other mental disorders in people undergoing specific treatment for any of them in Spain.

The co-occurrence of substance use disorders (SUD) and other mental disorders (OMD) is assumed to be high but is, in fact, unknown in Spain; and it is approached from different healthcare networks. The objective of the present study was to know the prevalence of this co-occurrence, both in specific addiction treatment networks and in mental health networks, in Spain. An observational, multicenter cross study, with a randomized sample, of patients under treatment for SUD or OMD in different Autonomous Communities of Spain was carried out (N=1,783). A specific ad hoc online questionnaire collecting sociodemographic variables, substance use and diagnoses of SUD and OMD was completed.The data obtained in the survey show a significant concurrence of SUD and OMD diagnoses (in more than 60% of the patients). A high prevalence of OMD was found in those patients receiving treatment for their SUD (71%), and also of diagnoses of any SUD (68.9%) and active substance use (50%, except tobacco) in people receiving treatment for diagnoses of OMD. Also were found significant relationships between addiction to certain substances and specific mental disorders: personality disorders with all SUDs; psychotic disorders with cannabis use disorder, but not cocaine use disorder; affective disorders with cocaine use disorder, and anxiety disorders with cannabis use disorder. This study provides preliminary information about the high coexistence in routine clinical practice of addictive disorders and other mental disorders in different treatment settings in Spain.