BDNF changes as a result of non-pharmacological interventions in schizophrenia – A scoping review

Abstract

Schizophrenia is a severe, chronic, neuropsychiatric disorder, with a complex, yet to be elucidated aetiology. The altered connectivity responsible for the wide range of symptoms in schizophrenia, stemming from genetic, metabolic, as well as environmental factors, has had researchers focusing on the identification of more and more “players” carrying certain specificity for the disease. One of these factors is the brain-derived neurotrophic factor (BDNF) - the most abundant growth factor in the central nervous system (CNS) and most frequently researched. Here, we set to explore the evidence pertaining to a correlational change in serum BDNF levels while individuals with schizophrenia undergo a non-pharmacological/psychotherapeutic intervention. We performed a systematic search of studies evaluating BDNF changes as a result of psychotherapeutic interventions in schizophrenia, in four databases: APA PsycInfo, Pubmed, Medline and EBSCO. The keywords “schizophrenia”, “psychotherapy OR psychosocial”, and “BDNF OR brain-derived neurotrophic factor” were searched for on all databases. The search yielded 46 titles and abstracts, of which 10 met the criteria for inclusion. The interventions consisted in neurofeedback, auditory training, cognitive remediation and lifestyle changes and behaviour therapy, as well as exercise. Serum BDNF levels were assessed systematically, showing significant increases as a result of the interventions in all studies, except three, where other changes are discussed. The studies discussed in this review support, overall, the idea of an increase in BDNF levels, as well as cognitive and clinical improvements secondary to non-pharmacological interventions. Several limitations and future directions are discussed.