Over the past few years I have become interested in looking at research about sibling relationships in psychotherapy, for a number of reasons. Many clients have openly talked about the impact of sibling relationships in their lives but, in other cases, I have also found it useful to consider that siblings may have been a background influence. For instance, there is evidence that having at least one sibling has a significant psychological effect on improving an individual’s conflict resolution skills.1 Clients are not usually very conscious of effects such as this – what they tend to be most conscious of is how unhappy or happy those relationships were and still are. But because sibling relationships are, for the majority of people, the longest relationships that they have in their lives, even if they are not the closest, they make a considerable difference.

In directly relational terms, some clients’ experiences of their sibling relationships may be a big influence on the way they relate to us as therapists and the role they see us playing in their lives. This sort of effect is worked with more consciously in psychodynamic-style groupwork, where current relating to others in the group is often compared with original family relationship styles. The intention is to bring to consciousness feelings and thoughts that may be influential so that they may be accommodated and detached from if they are unhelpful. The same may be said about constellations groupwork. In this article I explore how we may work with this more consciously in individual work, where such feelings and insights can still be fruitfully discussed and lessons learned from them.

Distance and intensity

When exploring the internal dynamics of their family in timeline work where the story involves childhood sibling relationships, there is often an intensity that is inexplicable in purely rational terms. This impression is also reflected in the way sibling relationships have tended to be written about in our culture, history and literature where two fairly distinct narratives tend to emerge: siblings as allies and siblings as tormentors. To quote an anonymous workshop participant: ‘If you don’t understand how a woman can both love her sister dearly and want to wring her neck at the same time, then you were probably an only child.’

What causes the relationship to have such intensity in the emotions felt around this? Dunn’s research2 has shed light on why sibling relationships are so intimate compared with those with peers and parents. Siblings spend long periods of time playing alongside, quarrelling, bargaining and recruiting each other into roles in projecting fantasies that are very personal. And they do this over many years and in changing circumstances, so that, over time, siblings assemble intimate knowledge of each other’s strengths and foibles, which are then used, for better or for worse, in each and every interaction. Thus these relationships are often highly charged, defined by intense, uninhibited emotions that often spill over in ways that puzzle parents and other onlookers.

Dunn’s research also reveals demographic trends in sibling relationships that can be helpful in predicting how people’s lives may have been, and may still be affected by early sibling relationships. For example, she has found that, even though same-sex siblings tend to get on better, they also tend to argue and fight more. Siblings with less than four years difference in age also tend to be more intimate, but also more competitive – there may be more envy, guardedness, secretiveness or guilt about having been the favourite.

Emotional functioning

This experience of intense interactions may have a considerable effect on clients’ mental health as adults, and their therapeutic process. For example, there is increasing evidence that several attributes help predict how quickly and well clients access insight and make progress in treatment. Among these, one quite promising line of research is into aspects of social emotional functioning – levels of empathy, self-awareness, trust and social skills or what has been termed in other literature ‘mentalisation ability’ or ‘psychological mindedness’. This has been shown in numerous studies to influence the therapy process, mostly in a positive way3 – psychologically minded clients tend to expect more of therapy and get more out of it. In the mental health field, mentalisation deficits are being increasingly researched in connection with a wide range of mental health conditions. Studies suggest that just having an older sibling can increase adult scores on the Empathy Quotient test,4 a key aspect of mentalisation. There is some suggestion that this effect is not universal, and is more emphasised for women, and may be reversed in the case of some men. That women tend to have higher Empathy Quotient scores generally and develop this trait earlier suggests that this difference in style of relating may start at an early age.

Overall, having siblings seems to influence sociability in general: adults who have had sibling relationships tend to participate more in group activities and team sports and, interestingly, in practical activities in general. Of course, sibling relationships are not the only, or may not even be the most important influence on everybody’s level of psychological mindedness and sociability, but it may be fruitful to bear in mind sibling relationships when exploring how well clients generally understand and get on with other people in their lives – how well they are supported socially, for example.

Attachment relationships

Sibling relationships may also play an important role in early attachment processes. In most Western theories of therapy, the quality of the parent-child attachment bond is seen as the most important, and ruptures and difficulties in this become the highest risk factor in psychological development, with many problems in life explained this way. But outside our present Western, nuclear family context, older sisters and brothers may be the most important attachment figures, especially when a mother’s time is very much taken up with her youngest offspring in a large family. We have seen this in the traumatic narratives of refugee children fleeing from war-torn areas: siblings may become the most vital connection where parents have been killed.

Sometimes in therapy, clients remember ruptures in close sibling relationships that they had tended to minimise but that may have left them feeling unsupported in a way that is hard to define. This emotional remembering has often then provoked memories of changes in sibling relationships that sometimes coincided with other pivotal points in their lives. These may be unacknowledged, but are something that can be usefully picked up and developed in timeline work.

In terms of the importance of sibling attachments, in some lines of research, it has been found that older siblings do tend to be predisposed to be responsive to younger siblings. In attachment tests, they tend to show protectiveness towards them. In my practice, working with one client on his history of dysfunctional family relationships, we rediscovered how his older sister had been crucial in saving his sanity by playing a protective role, rescuing him from the worst excesses of their distraught parent going through a very difficult time in life. This had quite an effect on both the giver and receiver of this protection, sometimes encouraging victim feelings, rescuer tendencies and a pathological avoidance of conflict.

Taking a broader perspective on the issue of wider attachment relationships, it is interesting to note that, evolutionarily speaking, humans are different from many other primates in allowing and encouraging a lot of alloparenting (parenting/childcare other than by the parent), and by a wide variety of other people; indeed an expression used in other parts of the world says that it takes a village to raise a child. Considered from this angle, it is not surprising that other relationships may have been very important to both survival and social and emotional development. Working cross-culturally, with more diverse populations, it becomes obvious that in the West we tend to be less conscious of wider family influences than of the direct influence we had from our parents, which is, of course, in keeping with the more fragmented, individuated norms that we live by. But among other cultural groups in the UK with more collectivist values and living in long-term extended family settings, familial obligations and roles still often play a much more important role in forming young people’s development, including their relationships with their siblings.

Interestingly, even within Western cultures, research shows that the closeness and quality of sibling relationships can often vary by socioeconomic status and gender. Close companionship with siblings tends to be more common in working-class and lower middle-class families, and they often continue longer in life, with siblings more likely to live near to each other and be active in each other’s social lives.5 This may also be one of the factors that helps to explain why people in these groups tend to use counselling services less and have higher levels of drop-out in treatment, as other forms of social support may be preferred to therapy, due to discrepancies in values and issues around unfamiliarity. With respect to gender, women in all walks of life tend to be more likely than men to maintain frequent contact with their siblings and, overall, affection seems to be stronger between sisters than between brothers or brothers and sisters.

Families as systems

Looking at sibling relationships in the context of families as systems, it has been found that siblings who are securely attached to parents, in general, tend to get on with each other better, and these positive overall family relationships tend to stimulate healthy emotion regulation in later childhood. Thus, science seems to support the cultural stereotype of ‘happy families’ behaving in certain ways, which is the basis of much TV advertising. However, what is often borne out in systemic family practice is that the internal family ‘narrative’ of happy childhoods is often what is particularly sought after and reinforced, but that this may cover a multitude of more complex unresolved feelings.

Another example of how sibling roles within the family system may be preserved into adulthood is how they may resurface at family gatherings, which can be reassuring for some, but may also be experienced as constricting and belittling by younger siblings. One particular client found it was liberating to acknowledge what was going on and develop assertiveness skills to challenge this unconscious assumption of roles.

Studies in social learning also show that siblings may be very important models for imitation, particularly in the teenage years, and these may have some considerable effect on early adult development, such as support in starting work and choice of career. At a time when teenagers are exploring identity, siblings may offer influential models, particularly if younger siblings have seen how their older sibling’s explorations have been responded to in the family system. It is also becoming clearer that many mental health conditions begin to emerge in mid-teenage years – clearly adolescence is an important developmental period in terms of determining mental health through the rest of the lifespan, and sibling relationships at this time may often play an important role.

On the role of social support, research shows that sibling relationships do tend to become closer in later life, and become more important as a source of social and emotional support and a barrier to loneliness. Sibling relationships may also help us to preserve our memories and the feelings attached to them, through repeated sharing of memories and photographs – an important element in remaining cognitively coherent in later life. This would be a fruitful area for further research.

The darker side

In research, negative sibling relationships are correlated with greater deviancy, substance misuse and criminality in adolescence, although it is often hard to tease out the effects of socioeconomic factors from sibling effects.

Some research shows that negative sibling relationships produce a tendency to internalise problems later in life, leading to more serious depression and anxiety conditions. Looked at in more specific detail, it has been found that sibling bullying is not uncommon; in one study, 30% of respondents had been hit by a sibling, and 54% reported that they had suffered some form of bullying by a sibling. The effects of sibling bullying can be profound and complex, as how the experience is integrated into the personal narrative can be subtle. As Hermann says, people tend to ‘construct a system of meaning that justifies it’ to help them to assimilate their experience.6 This may influence clients to minimise their overt blaming of siblings in their story, and instead focus on the general lack of parental control or neglect, but still reveal very uneasy feelings in the retelling. I have found that this sort of non-verbal communication is often very fruitful and interesting to explore.

It is interesting to note that in our Western culture there is a tendency for sibling conflict to be over-normalised as ‘rivalry’, but this may sometimes, in my experience, cover up some deep hurts that have been experienced by the sufferers, and may have led to having their feelings dismissed as ‘petty squabbling’. For one particular client, this experience had been pretty annihilating: in a scenario of insecure/dysfunctional family relationships, the cruelty of her older sister had greatly affected her general level of trust and confidence and led to deep shame issues. These had been hard for her to identify as an adult, because the treatment was seen as fairly normal in her family. Having an opportunity to re-evaluate the experience was very cathartic.

Another confounding factor in looking at sibling relationships is the belief that certain mental health disorders run in families: clients often seem to intuit and suggest this themselves. This ‘folk psychology’ can be hard to disentangle. I have sometimes found it useful to challenge some clients’ over-deterministic interpretation of genetic family influence – the research is not that simple.7 Transgenerational effects of attachment and trauma may be a more valid explanation for family members experiencing similar mental health issues. Dallos and Vitere8 found that people tend to react to their upbringing in two main ways: a script that replicates, or one that tries to repair or contradict it. Either way, many of the same issues become of greatest concern, which will tend to deeply affect them, and often come out in therapy.

In my own practice, I try to look at as wide a range of influences on a client’s current functioning as possible, and I have found quite often that one of these influences may be sibling relationships. I hope I have helped readers to look at the subject in a new light and gain some confidence in exploring how this may be affecting some of their clients.

Next in this issue


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4. Perner J et al. Theory of mind is contagious: you catch it from your sibs. Child Development 1994; 65; 4.
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8. Dallos R, Vitere A. Systemic therapy and attachment narratives: applications in a range of clinical settings. London: Routledge; 2009.