Introduction Research has shown that approximately 67% of carers experience extreme mental tiredness, a decrease in their quality of life and a deterioration in their physical health since taking on a care-giving role. Aims and objectives This study aims to identify factors that influence carer burden and in doing so, identify the sub-populations of carers who are most susceptible to burden. Methods In northwest Ireland, 53 informal carers referred to the Carers Association, Sligo were contacted and met for a face-to-face interview. Measurements used included demographic data, the Neuropsychiatric Inventory, Zarit Burden Interview, Social Network Index and Brown's Locus of Control Scale. Results Of the 53 carers, 43 were females and 10 males (age range: 32–81 years, mean age of 64.5 years). Of the corresponding 53 patients, 21 were females and 32 males (age range: 17–92 years, mean age of 72.1 years). Multiple linear regression analysis showed that sex of carer, marital status and the patient's behavioural problems were statistically significant independent factors, which influenced carer burden (p < 0.01). Female sex and greater patient behavioural problems increased susceptibility to burden and being married increased resilience towards burden. Conclusions: The ability to predict which carers are more susceptible to burden allows physicians to more quickly identify “higher risk” carers, facilitating routine check-ups by physicians and carer support services. Further research should explore why female and unmarried carers are more susceptible to burden and whether it is possible to tailor support services to their individual needs.