Parkinson’s disease (PD) is frequently compounded by neruropsychiatric complications, increasing disability. The combined effect of motor and mental status on care-dependency in PD outpatients is not well characterized. We conducted a cross-sectional study of 1449 PD outpatients. The assessment comprised the Montgomery–Asberg Depression Rating Scale (MADRS) and the diagnostic criteria for dementia. PD severity and treatment complications were rated using Hoehn and Yahr staging and the Unified Parkinson’s Disease Rating Scale (UPDRS) IV. The acknowledged level of care-dependency was documented. Care-dependency was present in 18.3% of all patients. A total of 13.9% had dementia, 18.8% had depression, and 14.3% had both. Regression analyses revealed increasing effects of age, PD duration, and PD severity on care-dependency in all three mental-disorder subgroups with the strongest effects in patients with depression only. Depressed patients with antidepressive treatment still had significantly higher PD severity, higher MADRS and UPDRS-IV scores but were not more likely to be care-dependent than non-depressed patients. Older age, longer duration and increased severity of PD contribute to care-dependency in patients with untreated depression. Treatment of depression is associated with lower rates of care-dependency.