Abstract
Apathy is a quantitative reduction of goal-directed activity, which can be observed in relation to behavior, cognition, emotions and social interaction. It is an invalidating behavioral symptom that is frequently present across different psychiatric conditions and neurocognitive disorders including Korsakoff's Syndrome (KS). In fact, apathy is one of the most severe behavioral symptoms of KS and has a major impact on the lives of patients and their relatives and other informal caregivers. However, guidelines for the treatment of apathy in KS are currently not available. This systematic narrative review provides a transdiagnostic overview of the effectiveness of different types of non-pharmacological interventions on apathy across different study populations that at symptom-level share characteristics with KS. This evidence may inform the development of an intervention targeting apathy in KS. The included study populations are dementia (due to Alzheimer's disease, or vascular dementia), Parkinson's disease, schizophrenia and traumatic brain injury. Through a stepped selection approach and with regard to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 22 systematic reviews and 32 empirical articles on the non-pharmacological treatment of apathy were identified. The results show a variety of effective non-pharmacological interventions on apathy. In conditions with severe cognitive impairments, successful interventions did not rely on intrinsic motivation, self-monitoring, or illness insight of the patients, but depend on external stimulation and behavioral activation. Since apathy is a multidimensional construct, identification of the extent and type of apathetic behavior before starting an intervention is highly recommended. Furthermore, it is important to adjust the treatment to the patients' personal interests and needs and embedded in daily care. TRIAL REGISTRATION: CRD42022298464 (PROSPERO).
