The impact of group composition on Internet support groups: Homogeneous versus heterogeneous Parkinson's groups.

We hypothesized that (a) members of homogeneous Parkinson’s disease (PD) Internet groups would show more commitment and attraction than heterogeneous groups and (b) members in homogeneous groups would show better outcomes. Six PD support groups, three heterogeneous and 3 homogeneous groups were composed on the basis of age and time since diagnosis. Cohesion, based on commitment and attraction, was measured using text analysis software measuring (a) the frequency of hope, positive feelings and thoughts, and affection linked to group as a target and (b) the frequency of “we,” “our,” and other words of inclusion. Pre–post changes were measured by depression, quality of life, and severity of PD. Multivariate analysis found that homogeneously composed groups were significantly more attracted and committed to their groups. A repeated measures multivariate analysis found that homogeneous groups showed significantly greater positive changes.