Negative symptoms are frequent in patients with schizophrenia and are associated with marked impairments in social functioning. The efficacy of drug-based treatments and psychological interventions on primary negative symptoms remains limited. The Positive Emotions Programme for Schizophrenia (PEPS) is designed to improve pleasure and motivation in schizophrenia patients by targeting emotion regulation and cognitive skills relevant to apathy and anhedonia. The main hypothesis of this study is that patients who attend 8 one-hour sessions of PEPS and treatment as usual (TAU) will have lower total apathy-avolition and anhedonia-asociality composite scores on the Scale for the Assessment of Negative Symptoms (SANS) than patients who attend only TAU.
Eighty participants diagnosed with schizophrenia or schizoaffective disorder were randomized to receive either TAU or PEPS + TAU. The participants were assessed by independent evaluators before randomization (T0), in a post-test after 8 weeks of treatment (T1) and at a 6-month follow-up (T2).
The post-test results and 6-month follow-up assessments according to an intention-to-treat analysis showed that the apathy and anhedonia composite scores on the SANS indicated statistically greater clinical improvements in PEPS participants than in non-PEPS participants. In the post-test, anhedonia but not apathy was significantly improved, thus favouring the PEPS condition. These results were sustained at the 6-month follow-up.
PEPS is an effective intervention to reduce anhedonia in schizophrenia. PEPS is a short, easy-to-use, group-based, freely available intervention that is easy to implement in a variety of environments (ClinicalTrials.gov ID: NCT02593058).