Objective: The goal of this month-long controlled study was to compare the efficacy of a second antidepressant (sAD) medication with a prescribed regimen of Plants vs. Zombies™ (PvZ), a casual videogame, in reducing treatment-resistant depression symptoms (TRDS) and improving heart rate variability (HRV). Materials and Methods: Approximately ∼8 weeks after beginning antidepressant therapy, participants returned to psychiatrists for evaluation and complained of TRDS. The psychiatrist gave them a choice of self-selecting a sAD medication or playing a prescribed regimen of PvZ as part of a research study. Those who agreed were referred to researchers who then screened them for major depression, the criteria for inclusion. PvZ was prescribed four times per week for 30-45 minutes over 4 weeks. Self-reported data were collected at four different times utilizing the Patient Health Questionnaire-9. HRV, an indicator of autonomic nervous system (ANS) functioning, was also recorded each time. Results: The sAD group's TRDS significantly improved. Remarkably, the PvZ group's TRDS improved significantly beyond the control group at all measurement times except for time 1 or baseline. In addition, a single 30-minute session of playing PvZ was significantly more effective in acutely reducing TRDS when compared with the sAD group that surfed the NIHM website on depression. Changes in HRV parameters indicated increased parasympathetic engagement and ANS balance in the PvZ group compared with the sAD group. Discussion: The findings illustrate the potential of PvZ as an acute and chronic intervention for reducing TRDS. Health care practitioners such as physicians and recreational therapists can consider recommending a regimen of prescribed PvZ play as a method to ameliorate symptoms of depression for those clients who self-select this option. Finally, a psychophysiological method for measuring the efficacy of videogames in reducing TRDS and a means to quantify ANS changes during gameplay are presented.
Keywords: Antidepressants; Casual videogames; Efficacy; Heart rate variability; Plants vs. Zombies; Treatment-resistant depression symptoms.