Family-Based Treatment (FBT) has the strongest evidence base among psychological treatments for adolescents with anorexia nervosa, yet a substantial proportion of young people do not achieve full recovery. One predictor of outcome is what happens very early in the treatment: adolescents who gain sufficient weight within the first few sessions are considerably more likely to do well later. This raises an important clinical question: If a young person is not responding early, should clinicians simply continue standard FBT, or should treatment be adapted? Lock, Le Grange, Bohon, Matheson, and Jo (2024) tested this question in a randomised clinical trial involving 107 adolescents with anorexia nervosa and their families. Young people who failed to gain 2.4 kg by session 4 were classified as early non-responders and randomly assigned either to continue standard FBT or to receive three additional sessions of Intensive Parental Coaching (IPC). The principal result was that adding IPC did not improve outcomes for early non-responders overall. However, the intervention appeared beneficial for a particular subgroup: families in which parents reported relatively low self-efficacy at the beginning of treatment. Rather than supporting routine augmentation of FBT whenever early progress is slow, the findings suggest a more targeted approach: monitor early weight gain, understand parents’ confidence in their ability to challenge anorexia, and adapt treatment when there is evidence that a specific family needs additional support.

Why early response matters

FBT places parents at the centre of the early recovery process, rather than expecting an adolescent who is acutely affected by anorexia nervosa to take sole responsibility for reversing restrictive eating. Parents are supported to take temporary control of nutrition and interrupt behaviours that maintain the disorder. An important feature of this approach is the expectation that change should begin early. Previous research has repeatedly shown that early weight gain predicts later outcome. Doyle et al. (2010) found that weight gain within the opening sessions of FBT was strongly associated with remission at the end of treatment. Le Grange et al. (2014) subsequently demonstrated a similar relationship across two treatments for adolescent anorexia nervosa (Hughes et al., 2019). Lock et al. (2024) used 2.4 kg of weight gain by session 4 as their marker of early response. This is clinically valuable because waiting until the end of treatment to decide that treatment has not worked offers little opportunity to change course. Early-response markers instead create the possibility of what the authors describe as an adaptive approach: treatment can be modified according to how the young person and family are actually responding.

Testing an adaptive version of FBT

The study recruited 107 adolescents aged 12–18 who met DSM-5 criteria for anorexia nervosa and were medically stable enough for outpatient treatment. All families initially received standard FBT. By session 4, 38 adolescents, approximately 36% of the sample, had gained at least 2.4 kg and were therefore classified as early responders. The remaining 69 young people had not reached this threshold. These early non-responders were then randomised to one of two conditions. One group simply continued standard FBT and the second continued FBT but received an additional three-session Intensive Parental Coaching intervention. The study, therefore, tested a clinical hypothesis: if inadequate early weight gain signals that standard treatment may not be sufficient, perhaps intervening specifically at that point could alter the trajectory. This approach followed promising earlier work. In a smaller feasibility study, Lock et al. (2015) found that introducing IPC for poor early responders was feasible and appeared capable of improving weight restoration. The current trial was designed as a more adequately test of that adaptive strategy.

What is Intensive Parental Coaching?

IPC does not replace FBT but intensifies early parental component. The intervention begins by making explicit that inadequate early weight gain is clinically significant. Then Parents and therapist meet without the adolescent to explore why weight restoration has been difficult and what may be preventing parents from successfully challenging anorexia. This is followed by a second therapeutic family meal in which parents can practise alternative strategies with direct therapist coaching. The emphasis is practical rather than simply psychoeducational and parents are helped to identify obstacles, develop new approaches and strengthen their ability to take action against eating-disorder behaviours.

Did adding IPC work?

Among adolescents who had failed to gain 2.4 kg by session 4, adding three IPC sessions did not produce superior remission or recovery compared with simply continuing standard FBT. When treatment appears to be progressing poorly, there is an understandable temptation to add something: more sessions, another therapeutic component, additional individual therapy or a different treatment strategy. Yet augmentation does not necessarily improve an already active treatment. The findings therefore provide some reassurance about continuing manualised FBT. An adolescent missing the early weight-gain threshold does not automatically mean that FBT should be abandoned or substantially altered. Indeed, the overall recovery rate in the trial was approximately 43%, broadly consistent with previous FBT research despite the relatively challenging nature of the sample.

Parental self-efficacy changed the picture

The effectiveness of IPC differed according to parental self-efficacy at baseline. Among families in which parents began treatment with lower confidence in their ability to combat anorexia and support weight restoration, adding IPC appeared substantially more beneficial. For this subgroup, the paper reports an increase in end-of-treatment weight remission from approximately 39% with standard FBT to 56% with FBT plus IPC. In contrast, families whose parents already had relatively high self-efficacy did not appear to benefit from the additional coaching.  Therefore, IPC may not be an intervention that every early non-responder needs but instead it may address a specific difficulty: parents who both encounter poor early weight gain and lack confidence in their ability to challenge the eating disorder.

From “Does FBT work?” to “For whom does this adaptation help?”

Adaptive trials ask a clinically relevant question: what should we do next for this particular patient or family, given how they have responded so far? The earlier comparison between FBT and systemic family therapy demonstrated that different forms of family treatment can produce substantial improvement, although FBT produced faster early weight gain (Agras et al., 2014). The current study goes further by examining heterogeneity within FBT response. Not every early non-responder is struggling for the same reason. For one family, parents may understand the treatment and feel confident but require more time to overcome entrenched eating-disorder behaviours. Another may struggle with parental anxiety, disagreement, uncertainty or a sense of helplessness. Treating those two families identically may be neither necessary nor efficient. Lock et al. (2024) therefore point toward a more precise model of adaptation: identify the obstacle before adding the intervention.

The importance of not abandoning FBT too early

Poor early response is prognostically important, but it is not the same thing as treatment failure. The 2.4 kg threshold helps identify adolescents at higher risk of poorer outcomes; it does not determine an individual adolescent’s destiny. Some early non-responders subsequently improve within standard FBT. This distinction matters clinically. The trial suggests that for most early non-responders, continuing well-delivered FBT remains reasonable. Adaptation appears most justified when early non-response is accompanied by evidence of a modifiable treatment obstacle, in this case low parental self-efficacy.

Measuring parental self-efficacy in practice

The Parents Versus Anorexia Nervosa Scale is a brief seven-item parental questionnaire (Rhodes et al., 2005). It assesses parents’ perceptions of their ability to take an effective role in defeating anorexia and supporting renourishment. If the result is replicated, clinicians would not require complex biological markers or expensive assessments to identify families who might benefit from IPC. They could potentially combine two pieces of readily available clinical information: Has the adolescent gained approximately 2.4 kg by session 4? And ¿How confident do the parents feel in their capacity to lead weight restoration? The combination may be more informative than either measure alone. Importantly, low parental self-efficacy should not be interpreted as parental inadequacy. Anorexia nervosa can generate extraordinary levels of fear, distress and conflict around eating. Parents may understand intellectually what needs to happen yet feel unable to tolerate the distress associated with making it happen. Within FBT, helping parents regain confidence is therefore a therapeutic task rather than a judgement about parenting.

Implications for clinical practice

Several practical messages emerge.

First, measure early response. Weight gain during the opening sessions of FBT contains clinically useful prognostic information (Doyle et al., 2010; Le Grange et al., 2014).

Second, do not equate early non-response with inevitable treatment failure. The findings do not support automatically abandoning or augmenting FBT whenever the 2.4 kg threshold is missed.

Third, look for the reason an adaptation might be needed. Parental self-efficacy may help distinguish families likely to benefit from additional coaching from those for whom more of the same intervention adds little.

Fourth, when parental confidence is low, additional coaching should be active and behaviourally focused. IPC involves identifying practical barriers, developing alternative strategies and practising them in a therapeutic family meal.

Finally, adaptation should preserve the core logic of FBT wherever possible. The study does not suggest replacing parental involvement when difficulties arise. Instead, it suggests increasing support for parents whose capacity to implement FBT is being overwhelmed.

Conclusion

Lock et al. (2024) offer a more sophisticated answer to the question of how Family-Based Treatment should respond to clinical complexity. The answer is not simply to add more treatment whenever early progress is poor. Early weight gain matters and failure to gain approximately 2.4 kg by session 4 identifies young people at elevated risk of poorer outcome. But among these early non-responders, additional parental coaching did not improve outcomes universally. Instead, who received the adaptation mattered. Parents entering treatment with relatively low self-efficacy appeared to be the group most likely to benefit from Intensive Parental Coaching. The clinical implication is therefore one of thoughtful adaptation rather than reflexive augmentation: monitor response early, assess what may be obstructing change, preserve the effective foundations of FBT, and intensify treatment when the additional component matches an identifiable family need. That approach moves FBT closer to personalised by becoming more precise about when, why and for whom it should be adapted.

Where next?

Join us on 29 October 2026 for a fantastic event on ‘Family-Based Treatment for Adolescent Anorexia Nervosa’ with Professor Daniel Le Grange.

Explore Family-Based Treatment (FBT) for eating disorders with its co-developer and internationally recognised expert, Professor Daniel Le Grange. This session will be emphasising adaptation in response to increasing clinical complexity. For nearly four decades, Professor Le Grange has been at the forefront of developing family-based treatments for adolescent anorexia nervosa and bulimia nervosa.

In this session, he will draw on extensive clinical research collaborations to revisit the foundations of the FBT model, examine how and for whom it works, and consider thoughtful adaptations where these may be warranted in response to increasing clinical complexity.

References

• Agras, W. S., Lock, J., Brandt, H., Bryson, S. W., Dodge, E., Halmi, K. A., Jo, B., Johnson, C., Kaye, W., Wilfley, D., & Woodside, B. (2014). Comparison of 2 family therapies for adolescent anorexia nervosa: A randomized parallel trial. JAMA Psychiatry, 71(11), 1279–1286. https://doi.org/10.1001/jamapsychiatry.2014.1025
• Doyle, P. M., Le Grange, D., Loeb, K., Celio-Doyle, A., & Crosby, R. D. (2010). Early response to family-based treatment for adolescent anorexia nervosa. International Journal of Eating Disorders, 43(7), 659–662. https://doi.org/10.1002/eat.20764
• Hughes, E. K., Sawyer, S. M., Accurso, E. C., Singh, S., & Le Grange, D. (2019). Predictors of early response in conjoint and separated models of family-based treatment for adolescent anorexia nervosa. European Eating Disorders Review, 27(3), 283–294. https://doi.org/10.1002/erv.2668
• Le Grange, D., Accurso, E. C., Lock, J., Agras, W. S., & Bryson, S. W. (2014). Early weight gain predicts outcome in two treatments for adolescent anorexia nervosa. International Journal of Eating Disorders, 47(2), 124–129. https://doi.org/10.1002/eat.22221
• Lock, J., Le Grange, D., Agras, W. S., Fitzpatrick, K. K., Jo, B., Accurso, E., Forsberg, S., Anderson, K., Arnow, K., & Stainer, M. (2015). Can adaptive treatment improve outcomes in family-based therapy for adolescents with anorexia nervosa? Feasibility and treatment effects of a multi-site treatment study. Behaviour Research and Therapy, 73, 90–95. https://doi.org/10.1016/j.brat.2015.07.015
• Lock, J. D., Le Grange, D., Bohon, C., Matheson, B., & Jo, B. (2024). Who responds to an adaptive intervention for adolescents with anorexia nervosa being treated with family-based treatment? Outcomes from a randomized clinical trial. Journal of the American Academy of Child & Adolescent Psychiatry, 63(6), 605–614. https://doi.org/10.1016/j.jaac.2023.10.012
• Rhodes, P., Baillie, A., Brown, J., & Madden, S. (2005). Parental efficacy in the family-based treatment of anorexia: Preliminary development of the Parents Versus Anorexia Scale (PVA). European Eating Disorders Review, 13, 399–405. https://doi.org/10.1002/erv.661