Relaxing Effect Induced by Forest Sound in Patients with Gambling Disorder

Abstract

The number of people addicted to gambling has increased worldwide. They often suffer from debilitating medical conditions associated with stress or depression. This study examined the physiological and psychological reactions of gambling disorder (GD) patients while listening to high-definition forest or city sounds using headphones. In total, 12 Japanese male GD patients were exposed to high-definition forest or city sound waves for 1 min via headphones. Near-infrared spectroscopy of the prefrontal cortex was used to examine oxyhemoglobin (oxy-Hb) concentrations. Heart rate and heart rate variability are indicators of autonomic nervous function. We performed subjective evaluation via the modified version of the semantic differential (SD) method with the profiles of the mood states (POMS). Experiencing forest sounds led to substantial differences as opposed to listening to city sounds: (1) oxy-Hb levels of the bilateral prefrontal cortices were lower (2) the modified SD method resulted in increased comfortable and relaxed feelings, (3) the negative POMS subscale scores were significantly lower, indicating that negative emotions diminished markedly when patients listened to forest sounds. This is the first study to show that sounds of forest relaxed individuals physiologically and psychologically to minimize GD.