Video game addiction now has a tentative diagnosis in the DSM-5, with its validity hinging on differentiation from close constructs and demonstrable negative consequences. Investigations of candidate consequences have produced mixed results. Deleterious correlates vary across studies, and the few which have investigated confounding factors or temporal precedence draw opposing conclusions. Resultantly expert opinions range from an example of dangerous superficial mental illness proliferation to a genuinely new, pathogenic condition. This PhD measured video game addiction, engagement and the possible negative consequences of diminished health (mental, social and physical) and functioning (at work, study, parenting and in romantic relationships), in adult avid gamers. Possible confounds included measures of satisfaction, stressful events, mental illness history, treatment seeking and coping styles. 506 geographically dispersed participants (84.7% male, mostly mid-twenties in age) were surveyed, with 111 returning to complete the measures six consecutive times. Life circumstances were diverse at baseline, with 62.8% working, 55.3% studying, 14.9% seeking work, 48.9% in a romantic relationship and 9.5% acting in a parenting role.