A pilot randomized clinical trial evaluating the impact of genetic counseling for serious mental illnesses

Abstract

Objective: The serious mental illnesses schizophrenia, schizoaffective disorder, and bipolar disorder are complex conditions affecting 1% to 4% of the population. Individuals with serious mental illnesses express interest in genetic counseling, an intervention showing promise for increasing patient knowledge and adaptation. This trial aimed to evaluate the effects of genetic counseling for people with serious mental illnesses as compared to an educational intervention or wait list.

Method: A pilot 3-arm (each n = 40; genetic counseling, a control intervention involving an educational booklet, or wait list), parallel-group, randomized clinical trial was conducted from September 2008 through November 2011 in Vancouver, Canada. Participants with schizophrenia, bipolar disorder, or schizoaffective disorder (DSM-IV) completed outcome measures assessing knowledge, risk perception, internalized stigma, and perceived control over illness at baseline and 1-month follow-up. The Brief Symptom Inventory was administered to control for current symptoms. Analyses included linear mixed-effects models and χ(2) tests.

Results: Knowledge increased for genetic counseling/educational booklet compared to wait list at follow-up (LRT1 = 19.33, Holm-adjusted P = .0003, R(2)LMM(m) = 0.17). Risk perception accuracy increased at follow-up for genetic counseling compared to wait list (Yates continuity corrected χ(2)1 = 9.1, Bonferroni P = .003) and educational booklet (Yates continuity corrected χ(2)1 = 8.2, Bonferroni P = .004). There were no significant differences between groups for stigma or perceived control scores.

Conclusions: Genetic counseling and the educational booklet improved knowledge, and genetic counseling, but not the educational booklet, improved risk perception accuracy for this population. The impact of genetic counseling on internalized stigma and perceived control is worth further investigation. Genetic counseling should be considered for patients with serious mental illnesses.

Trial registration: ClinicalTrials.gov identifier: NCT00713804.

Figure 1

Flow of participants through the trial ^a Abbreviations: SCID = Structured Clinical Interview for Diagnosis; KBIT-2 = Kaufman Brief Intelligence Test version 2; BSI = Brief Symptom Inventory (current symptoms); KRP = Knowledge and Risk Perception Questionnaire; ISMI = Internalized Stigma of Mental Illness Scale; IPQ = Illness Perception Questionnaire (perceived control); GCSS = Genetic Counseling Satisfaction Scale. At the time of study initiation, there were no existing data about the impact of GC for individuals with SMI, and the effect sizes for our outcome variables were unknown. Therefore, we based our a priori power calculation on the effect of GC for hereditary cancer on increasing knowledge and diminishing anxiety. ^bWe used diverse recruitment strategies to reach potential participants, including: posters in psychiatrists’ offices/waiting areas/inpatient units, online advertisements, direct approach at community mental health organizations’ meetings/events, direct approach at low-income housing units catering to those with mental illness, emails to mental health professionals and clients’ listservs, and mental health practitioners providing information about the study (recruitment brochure) to their patients. ^CFor the waitlist group, baseline and T1 occurred on the same day. Participants had the option of bringing a support person with them to appointments if they wished. In-person visits were arranged for some participants to complete the outcome measures at one month follow-up at their request. One of the participants in the waitlist group had received GC for SMI prior to the study. The trial was stopped once the pre-determined number of participants had been recruited and those who were not lost to follow up had completed the study. The full protocol can be obtained from the corresponding author. ^dOne patient discontinued participation because of rapid exacerbation of illness.

Figure 2

a) Mean knowledge scores by group and time, b) Mean ISMI alienation subscale scores by group and time. All error-bars represent 95% CI.