There's a huge amount more I could reflect on about the group.  I'll keep it here, though, to just a final set of thoughts about the overlapping field of group therapy.  These peer groups are about all kinds of things - friendship, wellbeing, ‘retreat', fun - and they are also about work on ourselves that is in significant ways ‘therapeutic'.  Group therapy is effective.  The "Group therapy - background information" leaflet (see below) discusses this in more detail.  Group therapy seems to produce its benefits through a whole series of overlapping mechanisms.  In a handout/questionnaire I've produced for the groups that I run, I've written: 

Why bother to understand the mechanisms of improvement?  Surely what's really important is that people gain worthwhile benefit from being involved in therapy groups - why bother to try to understand better why these improvements occur?  An obvious answer to this question is that, if we know what therapeutic factors are most beneficial, these aspects of group work can be emphasised so that people gain as much as possible from their participation in the group.

Yalom's classic text 'The theory and practice of group psychotherapy' was hailed by Jerome Frank as 'the best book that exists on the subject today, and for the foreseeable future'.  The first edition came out in 1970 and the fifth edition in 2005.  Yalom detailed a series of research studies asking participants to rate sixty therapeutic factors.  These factors were grouped into 12 categories: 1.) group cohesiveness 2.)  altruism. 3.) universality. 4.) interpersonal learning (input).  5.) catharsis.  6.) instillation of hope.  7.) interpersonal learning (output).  8.) identification.  9.) family re-enactment.  10.) self-understanding.  11.) guidance.  12.) existential factors.  Typically interpersonal factors, catharsis and group cohesiveness are rated very highly.  There is considerable variation though - with the type of group studied, with how long the group has been meeting for, and with the participant's level of functioning and personality style.

The handout/questionnaire "How does group therapy produce benefits?" (see below) makes these points and also includes a 20 item questionnaire covering many of the most frequently endorsed of the 60 therapeutic factors enumerated by Yalom.  It's an interesting questionnaire to fill in, and there's space too for personal factors not described on the list.

So typically interpersonal factors, catharsis and group cohesiveness are rated very highly.  Interestingly Self-Determination Theory researchers looking at key determinants of group mood and commitment (Sheldon and Bettencourt, 2002) in a variety of formal and informal groups found that group inclusion seemed of particular importance.  This chimes in with findings from early group therapy research (Budman, Soldz et al. 1989) demonstrating links between group cohesion in group therapy and therapeutic alliance in one-to-one therapy.  In another early study (Hurley and Brooks, 1987), researchers found of particular importance in predicting benefit was the answer to the single question rated on a 0 to 6 scale "The members liked and cared about each other" with options - "Not at all" (0), "A little bit" (1), "Somewhat" (2), "Moderately" (3), "Quite a bit" (4), "A great deal" (5), and "Extremely" (6).

Fascinatingly it looks as though this warmth and inclusiveness very much needs to be within a setting of fairness, honesty and sincerity.  Recent research (Leach, Ellemers et al. 2007) suggests that perceived group morality is more important than perceived group sociability or competence when people evaluate a group they belong to.  Morality, in this research, was assessed by answers to questions about honesty, sincerity and trustworthiness within the group.  I've often thought a key ‘entry card' to these peer groups we're involved with is a commitment to both being personally authentic & genuine at the same time as respecting & considering how others are in the group.  It's interesting though that this quite extensive research found morality was more important for positive group identification than sociability (measured by questions about likeability, warmth & friendliness) or competence (measured by questions about competence, intelligence & skill).

It links back to the Rogerian triad - the "three-legged stool" - that I find so helpful as a simple guide to key qualities for building close relationships.  The qualities are empathy/sensitivity, respect/caring, and genuineness/authenticity.  The handout "Communication scales" (see below) gives more detail here and adds in the Carkhuff et al quality of concreteness as well.  It links too to the answer given by a dear friend when asked, in one of these peer groups, about the purpose of the group.  He said "We're here to learn to love".  Spot on.

Budman, S. H., S. Soldz, et al. (1989). "Cohesion, alliance and outcome in group psychotherapy." Psychiatry 52(3): 339-50.  [PubMed]
Hawkins, James.  "Group therapy - background information".  Handout.
Hawkins, James.  "How does group therapy produce benefits".  Handout/questionnaire.
Hawkins, James.  "Communication scales".  Handout.
Hurley, J. R. and L. J. Brooks (1987). "Group climate's principal dimension: affiliation." Int J Group Psychother 37(3): 441-8.  [PubMed]
Leach, C. W., N. Ellemers, et al. (2007). "Group virtue: the importance of morality (vs. competence and sociability) in the positive evaluation of in-groups." J Pers Soc Psychol 93(2): 234-49.  [PubMed]
Sheldon, K. M. and B. A. Bettencourt (2002). "Psychological need-satisfaction and subjective well-being within social groups." Br J Soc Psychol 41(Pt 1): 25-38.  [PubMed]  [Free Full Text]
Yalom, Irvin.  "The theory and practice of group psychotherapy (5^th edition)."  New York: Basic Books, 2005.   [AbeBooks]  [Amazon UK]