The purpose of this study is to pilot test a peer-delivered decision support intervention ("peer decision coaching") designed to enhance decision-making about community participation among young adults with serious mental illness (SMI).

The overarching goal of this study is to pilot test a peer-delivered decision support intervention ("peer decision coaching") designed to enhance decision-making about community participation among young adults with serious mental illnesses (SMI). We will use a single-group, pre-post, convergent mixed methods design to explore implementation and whether and how the intervention impacts decision-making and community participation outcomes. We will aim to recruit 40 participants in this intervention study. This design will enable us to link themes regarding participants' experience of the intervention with quantitative measures of decision-making and community participation.

Inclusion Criteria:

• 18-30 years of age;
• Experiencing a SMI, as determined by: (a) self-reported psychiatric diagnosis of schizophrenia-spectrum or major affective disorder, and (b) self-reported current or past functional impairment due to experiencing mental health challenges in one or more major life areas (i.e., work school, social activities)
• Able to identify at least 2 areas of community participation that individuals want to be doing more in in the next 6 months
• Current sufficiency of community participation (i.e., number of important participation areas done enough / number of important participation areas) of 50% or less.

Exclusion Criteria:

• Unable to provide informed consent, as assessed by research staff using an active recall method
• limited ability to act on decisions due to self-reported legal, residential, or guardianship restrictions.