Third, health variables consisted of: (1) depression symptoms, coded 1 if the respondent reported having felt depressed and 0 if not; (2) smoking, coded 1 if the respondent reported smoking and 0 if not; (3) diabetes medication, coded 1 if the respondent reported taking oral medication for diabetes and 0 if not; and (4) insulin, coded 1 if the respondent reported taking insulin and 0 if not. The gene discussed is INS; the disease is major depressive disorder.