Patients with schizophrenia are frequently diagnosed with addictive comorbidities, and data in the literature support a 10 to 70% prevalence of this dual diagnosis. Nonetheless, substance use disorders can be missed during the initial interview with a psychotic patient, if the clinician is focused only on the more obvious manifestations. Therefore, using psychometric scales and structured interviews in patients with schizophrenia is strongly encouraged because the case manager will base his/her therapeutic decisions on quantifiable data about these patients’ symptoms and functional status. Clinical management in dual diagnosis cases must address both conditions simultaneously, as the delay in the initiation of substance withdrawal treatment may hinder the recovery from a psychotic episode. An important issue is represented by the potential pharmacologic interactions between drugs administered for schizophrenia and those targeting substance withdrawal and substance dependence. Other important aspects refer to (1) the therapeutic adherence, which can influence the prognosis of both conditions, (2) the negative impact of residual psychotic symptoms and substance-related disorders over the patient quality of life and daily functioning, (3) the necessity to integrate variables like the patient’s specific needs, lifestyle, and psychological resources in the therapeutic decision. These clinical vignettes are focused on clinical, biological, psychometric, and pharmacological dimensions, supporting the formulation of treatment recommendations based on monitoring both psychiatric and biological profiles.
Background: A large number of augmentation agents have been tried in patients with schizophrenia spectrum disorders, because negative and cognitive symptoms are difficult-to-treat with current pharmacological agents, and because the high percentage of treatment-resistant cases requires new therapeutic solutions. Inflammation is one of the supposed pathophysiological mechanisms in schizophrenia; therefore, antibiotics have been explored as add-on agents. No systematic review or meta-analysis about the efficacy of antibiotics in psychotic disorders has yet been conducted. Objectives: To assess if the use of antibiotics as add-on to current antipsychotic treatment may improve core symptoms of schizophrenia spectrum disorders, global clinical status, overall functionality, and if this augmentation strategy is well tolerated. Methods: A systematic literature review was conducted, including papers published between 1980 and 2018, which have been found in the main electronic databases (PubMed/MEDLINE, CINAHL, NCBI, Embase, Thomson Reuters/Web of Science). The keyword search strategy was formulated using the following paradigm: „schizophrenia spectrum disorders”/ „schizophrenia”/ „schizo-affective disorder”/ „schizophreniform disorder”, AND „antibiotics”/ all the names of currently marketed antibiotics classes. This review was registered to PROSPERO database with the protocol number CRD42019119152. Results: Based on reviewing the selected trials regarding the efficacy of antibiotics over core symptoms of schizophrenia, only two agents were detected – minocycline and D-cycloserine. Minocycline as add-on to antipsychotic treatment was associated with mixed results, while regarding the efficacy of d-cycloserine either no significant difference, or superiority to placebo over negative and cognitive symptoms was reported. Minocycline had an overall effect over the clinical impression that was not distinguishable from placebo, although there was one trial supporting the efficacy of this antibiotic. The impact of minocycline over the global functioning when added to antipsychotic in patients with schizophrenia was mixed, with one positive and one negative trial (moderate to high quality designed trials). D-cycloserine had no significant impact over global clinical status or patients’ overall functionality. Conclusion: From all the data reviewed and hierarchized resulted that larger trials are needed in order to confirm the efficacy of antibiotics as add-on to antipsychotics over negative and cognitive symptoms of schizophrenia spectrum disorders.
