A drug delivery device comprising: a housing (52, 610) defining an interior cavity and a distal surface (102, 625) for contacting a patient during a dispensing operation of the drug delivery device; a primary container (62, 612) disposed in the interior cavity of the housing and adapted to contain a drug; a cannula (54, 614) having an electrically conductive portion, the cannula having a storage state where a terminal end (58, 618) thereof is inside the housing and a delivery state where the terminal end thereof extends out through an opening (107, 607) in the distal surface of the housing; a fluid flow path (62, 663) for the drug including the primary container and the cannula; a delivery mechanism (150, 630) disposed in the housing for selectively forcing the drug through the fluid flow path out of the primary container and through the cannula for delivery to a patient when the cannula occupies the delivery state; a flow measurement device (61, 661) configured to measure a characteristic of the flow of the drug forced through the fluid flow path; an electrode disposed on the distal surface of the housing; and a controller (60, 660) carried by the housing and electrically connected to the flow measurement device, the cannula, and the electrode, the controller configured to determine whether the drug was successfully delivered to a patient by: determining that an electrical circuit (105, 605) including the cannula and the electrode has closed upon application of the electrode on the distal surface of the housing onto a patient's skin and insertion of the cannula into the patient; and determining, based on the measurements of the flow measurement device and in combination with recognizing the closed electrical circuit, whether a full dose of the drug has been forced through the fluid flow path and delivered to the patient. a housing (52, 610) defining an interior cavity and a distal surface (102, 625) for contacting a patient during a dispensing operation of the drug delivery device; a primary container (62, 612) disposed in the interior cavity of the housing and adapted to contain a drug; a cannula (54, 614) having an electrically conductive portion, the cannula having a storage state where a terminal end (58, 618) thereof is inside the housing and a delivery state where the terminal end thereof extends out through an opening (107, 607) in the distal surface of the housing; a fluid flow path (62, 663) for the drug including the primary container and the cannula; a delivery mechanism (150, 630) disposed in the housing for selectively forcing the drug through the fluid flow path out of the primary container and through the cannula for delivery to a patient when the cannula occupies the delivery state; a flow measurement device (61, 661) configured to measure a characteristic of the flow of the drug forced through the fluid flow path; an electrode disposed on the distal surface of the housing; and a controller (60, 660) carried by the housing and electrically connected to the flow measurement device, the cannula, and the electrode, the controller configured to determine whether the drug was successfully delivered to a patient by: determining that an electrical circuit (105, 605) including the cannula and the electrode has closed upon application of the electrode on the distal surface of the housing onto a patient's skin and insertion of the cannula into the patient; and determining, based on the measurements of the flow measurement device and in combination with recognizing the closed electrical circuit, whether a full dose of the drug has been forced through the fluid flow path and delivered to the patient. determining that an electrical circuit (105, 605) including the cannula and the electrode has closed upon application of the electrode on the distal surface of the housing onto a patient's skin and insertion of the cannula into the patient; and determining, based on the measurements of the flow measurement device and in combination with recognizing the closed electrical circuit, whether a full dose of the drug has been forced through the fluid flow path and delivered to the patient.