Aims Carer distress in Parkinson's disease (PD) has been associated with psychiatric symptoms and levels of disability and disease severity in the PD sufferer. The specific contribution of behavioural phenotype in PD (impulsive vs apathetic) to carer burden has not yet been fully explored.

Methods Non-demented (n=71) PD sufferer-carer dyads (spouse or child) were examined on various measures. The PD sufferers were divided into three behavioural groups: impulse control disorder (ICD) (n=21); apathy (n=22); and controls (n=28). Carer burden was rated using the Zarit Burden Scale and carer distress was determined from the Neuropsychiatric Inventory. PD sufferers were assessed for levels of disability, quality of life, clinical (motor and psychiatric), demographic variables and cognitive function. Correlations between variables were sought.

Results The three behavioural groups differed significantly on measures of carer burden, with the ICD and apathy group carers’ having a greater burden of care. The PD groups differed significantly in levels of disability, psychiatric morbidity, cognitive functioning and clinical variables. Strong correlations were found between measures of psychiatric morbidity and carer burden (UPDRS Mental dysfunction score: ñ=0.453, p<0.001) and distress (Global Assessment of Functioning: ñ=−0.636, p<0.001).

Conclusions Carer burden and distress differ according to behavioural phenotype, which appears to be driven by differences across several clinical factors.