Lifestyle MIND- Feasibility of Wait-list Control

The goal of this clinical trial is to examine if it is feasible to randomly assign people into two groups and participate in Lifestyle MIND (Mental Illness and/N\' Diabetes) at two different times. Lifestyle MIND is a diabetes lifestyle intervention recently developed for people with serious mental illness (SMI). It is known to be helpful for people with SMI who complete it, but the investigators do not know the effect in comparison to those who do not participate in it. The main questions it aims to answer are: * Does Lifestyle MIND improve diabetes control among people with SMI? * Will the effect of Lifestyle MIND be sustained 10 weeks after program completion? * From the provider\'s perspective, what are the barriers of achieving optimal diabetes treatment outcomes for patients with SMI? Researchers will compare outcomes of participants in the intervention with those in the wait-list control arm, to see if there will be significant differences in blood glucose level, compliance of diabetes self-management, time staying active, number of emergency department (ED) visits and psychiatric hospitalization, and subjective well-being.