This paper describes the first approach in synthesizing mood-affected signed contents. The research focuses on the modifications applied to a parametric sign language synthesizer (based on phonetic descriptions of the signs). We propose some modifications that will allow for the synthesis of different perceived frames of mind within synthetic signed messages. Three of these proposals focus on modifications to three different signs' phonologic parameters (the hand shape, the movement and the non-hand parameter). The other two proposals focus on the temporal aspect of the synthesis (sign speed and transition duration) and the representation of muscular tension through inverse kinematics procedures. These resulting variations have been evaluated by Spanish deaf signers, who have concluded that our system can generate the same signed message with three different frames of mind, which are correctly identified by Spanish Sign Language signers.