Systems and methods for stimulation of neurological tissue and generation stimulation trains with temporal patterns of stimulation, in which the interval between electrical pulses (the inter-pulse intervals) changes or varies over time. The features of the stimulation trains may be selected and arranged algorithmically to by clinical trial. These stimulation trains are generated to target a specific neurological disorder, by arranging sets of features which reduce symptoms of that neurological disorder into a pattern which is effective at reducing those symptoms while maintaining or reducing power consumption versus regular stimulation signals. Compared to conventional continuous, high rate pulse trains having regular (i.e., constant) inter-pulse intervals, the non-regular (i.e., not constant) pulse patterns or trains that embody features of the invention provide increased efficacy and/or a lower than average frequency.