Psychiatric symptoms screening in the early stages of Parkinson's disease

Psychiatric complaints are common in Parkinson's disease (PD), and have a significant influence in disease outcome and quality of life. Little attention has been paid to psychiatric symptoms at early stage disease. We aimed to screen a population of early stage PD patients for psychiatric symptoms and to study the relation with motor and cognitive function. Thirty-six early stage PD patients underwent motor [Hoehn and Yahr (HY), Unified Parkinson's Disease Rating Scale] and cognitive [Frontal Assessment Battery, Mini-Mental State Examination (MMSE)] assessment as well as general psychiatric [Symptom Check-List 90 (SCL-90-R)] and psychosis [Brief Psychiatric Rating Scale (BPRS)] screening. Relation between psychiatric domains scores was studied with principal component analysis. Relation between psychiatric, disease related, cognitive and motor function was assessed with bivariate correlation (Pearson). SCL-90-R scores were higher for somatization (significant scores in 66.7% of patients), depression (36.1%), anxiety (27%) and obsessive-compulsive symptoms (OCS) (52.8%). Scores were highly correlated, except for psychosis and phobia. Depression and anxiety were negatively correlated to MMSE score and dopaminergic doses, respectively. BPRS scores were higher for somatic concern, depression, anxiety and hallucinations. There was segregation between depression, anxiety, hallucinations, other positive psychotic symptoms and negative psychotic symptoms. Depression was related to MMSE score. We found a high prevalence of psychiatric complaints in PD patients, mostly related to depression, anxiety, somatization and OCS. Hallucinations were also frequent, but not associated to cognitive function or dopaminergic doses, suggesting a different physiopathological background.