Psoriasis treatment responses are affected by patient characteristics. However, the literature does not contain reviews of factors that affect the response to biologic therapies. We therefore performed a comprehensive literature search to identify papers describing demographic, lifestyle, and clinical factors associated with response to biologic drug therapy in psoriatic patients. We found that age, gender, ethnicity, alcohol consumption, smoking, geographic location, age at diagnosis, duration and severity of psoriasis, and baseline C-reactive protein levels did not consistently affect response to biologic psoriasis therapy. However, increased body mass index (BMI) appears to adversely affect responses. It might therefore be valuable to include BMI as a stratification variable in future studies of psoriasis therapies and to consider a patient's weight or BMI when selecting a systemic psoriasis treatment.