Mustain holds a Bachelor of Science in Psychology with an emphasis on Substance Abuse Treatment as well as a Master's Degree in Clinical Psychology from Pittsburg State University. Mustain became a Licensed Master Level Psychologist in 2003, and became a Substance Abuse Counselor of Kansas in 2000, Kansas Certified Gambling Counselor in 2008, and became a Licensened Clinical Addiction Counselor in 2011. Mustain started at LCMHS as a case manager and counselor in the Substance Abuse Program in 2000. Mustain assumed the responsibility of Coordinator for the Substance Abuse Program in 2002 and remained in that position until 2008 when she was named Community Support Services Coordinator. In 2012 Mustain became the Director of Specialty Services over the Community Support Services program serving the adult population as well as the Community Based Services program serving the children population. She then became the Director of Clinical Programs, overseeing outpatient services in addition to the specialty programs, in 2013.