Cognitive behavioural therapy (CBT) is an effective treatment for depression, but a significant minority of clients are difficult to treat, including those with histories of relational trauma. The model of Beck et al. (1979) proposes that adverse childhood experiences lead to negative core beliefs, and these create a susceptibility to depression. However, Beck’s model does not identify trauma as a subset of adverse experiences. An alternative view is that traumatised clients internalise conflicting representations of self and it is conflict, interacting with trauma memories, that creates a vulnerability for depression. In this formulation, methods from the treatment of post-traumatic stress disorder (PTSD) could be incorporated into the treatment of depression, to emotionally process trauma memories and resolve self-identity conflicts. The aims of this study were to: (1) report the treatment of a 67-year-old man with recurrent depression and a history of prolonged relational trauma, and (2) to explore how memory processing from the treatment of PTSD can be incorporated into the treatment of recurrent depression. A single case observational design was used in the long-term treatment of a depressed traumatised client. The client received 47 individual sessions over 19 months in routine clinical practice in a tertiary CBT service. He completed repeated measures of mood, memory intrusions and sleep disruption. The client responded well to treatment with clinically significant improvements across measures of mood, memory and sleep. The effects were sustained over an 18-month follow-up. Memory processing was successfully integrated into a high-intensity treatment for recurrent depression. This is a promising approach for depressed clients with histories of relational trauma.

Cognitive behavioural therapy (CBT) is an effective treatment for depression but a significant minority of clients are difficult to treat: they are more likely to have adverse childhood experiences, early-onset depression, co-morbidities, interpersonal problems and heightened risk, and are prone to drop out, non-response or relapse. CBT based on a self-regulation model (SR-CBT) has been developed for this client group which incorporates aspects of first, second and third wave therapies. The model and treatment components are described in a concurrent article (Barton et al., 2022). The aims of this study were: (1) to illustrate the application of high dose SR-CBT in a difficult-to-treat case, including treatment decisions, therapy process and outcomes, and (2) to highlight the similarities and differences between SR-CBT and standard CBT models. A single case quasi-experimental design was used with a depressed client who was an active participant in treatment decisions, data collection and interpretation. The client had highly recurrent depression with atypical features and had received several psychological therapies prior to receiving SR-CBT, including standard CBT. The client responded well to SR-CBT over a 10-month acute phase: compared with baseline, her moods were less severe and less reactive to setbacks and challenges. Over a 15-month maintenance phase, with approximately monthly booster sessions, the client maintained these gains and further stabilized her mood. High dose SR-CBT was effective in treating depression in a client who had not received lasting benefit from standard CBT and other therapies. An extended maintenance phase had a stabilizing effect and the client did not relapse. Further empirical studies are underway to replicate these results.

Cognitive behavioural therapy (CBT) for major depression is an effective treatment, but outcomes for complex cases, with co-occurring biological, psychological and social factors, are variable. Complexity factors can cause treatment to become diffuse, disorganized and over-complicated. At Step 3, disorder-specific protocols should be provided with therapy kept as simple as possible and delivered responsively, e.g. barriers to treatment should be tackled, ensure the client is well-prepared and seek to form a strong therapeutic alliance. At Step 4, if disorder-specific protocols have been ineffective, the priority is to formulate how complexity factors are interacting with the client's depression. An individualized formulation is used to carefully target these interactions. The treatment is still evidence-based and simple at the point of delivery, but there is greater emphasis on case-level interactions that are unique to each individual. Case examples are used to illustrate both approaches.

As therapists we frequently use and hear the term ‘complexity’ in relation to clients, situations and settings. Although we may assume there is a shared understanding of what is meant by complexity, is this true? Do we really know what we mean by describing someone, or something, as complex? If we define complexity as ‘consisting of many different and connected parts, not easy to analyse or understand’ (Oxford English Dictionary, 2017), then we are probably describing intersections and interactions between different elements that can influence each other. Interestingly, the origin of the term derives from the Latin past participle plexus, meaning braided or entwined, which captures neatly the sense of the term ‘complex’ as meaning literally braided together. The breadth of this definition therefore may help to account for the diversity of the ways in which the term complexity is used in clinical settings. Continuing with the idea of the plait or braid, it also gives a sense of the number of threads or strands that could be incorporated within such a system. Complexity can derive from any source, and can interact with any part, so it can derive from the patient, the therapist, the therapeutic relationship or the healthcare setting; and each of these may interact with one or more parts. So from any source, complexity can affect processes and outcomes of care.

This essay is a social-scientific study of Paul's deployment of holiness language in 1 Corinthians. Specifically, an interpretation of holiness is offered to explain Paul's argument in 1 Cor 7.12–16 in favour of non-separation in the case of a believer married to a non-believer. For Paul, holiness involves participation in the oneness of God interpreted christologically. This participation is embodied in the holiness-as-oneness of the church. In relations between believers and unbelievers, purity rules to do with sex and marriage carry a significant symbolic burden. In some cases, clear lines of demarcation are drawn. Other cases constitute grey areas; and the suggestion here is that ‘mixed marriages’ are one such. For Paul, holiness is a matter of neither genealogical nor cultic purity. Rather, it has a boundary-transcending quality. In the case of a mixed marriage, the unbelieving partner, together with the children, is sanctified by remaining in oneness with the believing partner. Paul's concern for the oneness of the church spills over into a concern for the oneness of the household.