Contributions of Humanistic Psychotherapy to the Treatment of Post-Traumatic Stress Disorder or Trauma-Associated Symptoms: A Systematic Review

Introduction

Psychological trauma refers to the emotional wound that remains after a person experiences a situation that overwhelms their processing capacity and threatens their survival. This wound can be manifested at the emotional, physiological, behavioral, as well as cognitive levels, and impact the brain’s executive functions, a person’s self-esteem, and the way one relates to oneself and others (Van der Kolk, 2014). The Diagnostic and Statistical Manual of Mental Disorders (DSM-V-TR; American Psychiatric Association [APA], 2022) includes post-traumatic stress disorder (PTSD) as a diagnostic label for individuals who have been exposed to a traumatic event through direct experience, witnesses, exposure to repeated or extreme details, or knowledge that the event occurred to a close family member or friend. After the exposure, they manifest several characteristics from four symptom clusters (intrusion, avoidance, negative alterations in cognition and mood, and hyperarousal) for at least 1 month. Nevertheless, a person may exhibit trauma-related symptoms and require specialized psychological treatment even without meeting all the criteria for a PTSD diagnosis.

Moreover, a person may experience a single traumatic event or face an accumulation of traumatic events. Repeated exposure to traumatic experiences has been shown to increase the complexity of PTSD symptoms (Cloitre et al., 2009). Some authors argue that there should be a separate diagnostic category for this phenomenon currently referred to as complex trauma, because traumatic situations are more diverse, and the resulting effects on the individual are deeper due to the cumulative harm and the need to develop adaptive survival strategies in a traumatizing context (Nieto Martínez & López Casares, 2016).

In addition to PTSD and complex trauma, other authors speak to the existence of attachment trauma. Based on Bowlby’s attachment theory (1989), this refers to psychological harm experienced by an individual after suffering episodes of hostility from their attachment figures during childhood (Bowlby, 1989). Such episodes can range from physical aggression to verbal or physical rejection, emotional abandonment, neglect, or devaluation. This type of trauma can lead to diverse forms of psychological harm (Lahousen et al., 2019), as well as to the development of pathologies in childhood (Haliburn et al., 2011) and the emergence of somatic symptoms in adulthood (Sansone et al., 2009).

Due to the magnitude and breadth of the damage caused by experiencing one or more traumatic situations, individuals with PTSD or trauma-related symptoms often develop other conditions such as depression, anxiety, behavioral, or substance abuse-related disorders (APA, 2022), among others. In terms of treatment, the main goal is to help the person regain control over their mind and body, as well as their ability to self-regulate (Van der Kolk, 2014). This might be divided into four sub-goals (Van der Kolk, 2014): (a) achieving a state of calm and focus; (b) maintaining this calmness when confronted with stimuli that trigger memories of the traumatic event; (c) fully living in the present and interacting with the environment; (d) no longer needing to hide aspects of oneself, the traumatic event, or survival strategies, thus freeing oneself from shame and guilt.

According to a recent meta-analysis (Mavranezouli et al., 2020), the psychological therapies with the most empirical support received to date for treating PTSD in adults are Cognitive Behavioral Therapy (CBT) and Eye Movement Desensitization and Reprocessing (EMDR). Both are trauma-focused, directive therapies which share a common technique, exposure to trauma-related stimuli, with the aim of reducing the distress they cause in the individual (Jericho et al., 2021; Morris et al., 2021). Moreover, Trauma-Focused Cognitive-Behavioral Therapies (TF-CBT) have proven to be more effective than pharmacological interventions in reducing PTSD symptoms and comorbid psychopathologies (Coventry et al., 2020). Within TF-CBT, the National Institute for Health and Care Excellence (NICE, 2018) more specifically recommends Cognitive Processing Therapy (CPT), Narrative Exposure Therapy (NET), and Prolonged Exposure Therapy (PET) as first-line treatments. EMDR is considered a second-line option when a patient does not adhere to or benefit from the previous therapies.

However, one of the limitations of these therapies is the high dropout rate among patients. Research has evaluated the efficacy of CBT for victims of gender-based violence with PTSD and recorded a 24% dropout rate (Santandreu & Ferrer, 2014). Similarly, a systematic review of effective treatments for adults suffering PTSD as a result of terrorist attacks has shown dropout rates in CBT groups ranging from 0% to 53%, with an average of 22.7% (García-Vera et al., 2015). Additionally, one study testing the efficacy of TF-CBT for victims of terrorism with PTSD reported a 28.6% dropout rate (Gesteira et al., 2018). Later, research specifically focused on dropout rates in PTSD therapies found that, on average, 16% of patients discontinued therapy (Lewis et al., 2020). When focusing only on cognitive-behavioral and EMDR therapies, this figure rose to 19.9%. This phenomenon was explored in a group of patients aged 7 to 17 who were receiving TF-CBT, and a 26.8% dropout rate was found (Yasinski et al., 2018). It was concluded that avoidance symptoms and difficulty establishing a therapeutic alliance in the early sessions were predictors of therapy dropout.

Establishing such a therapeutic alliance right from the outset is crucial when working with any patient. However, for individuals who have experienced traumatic situations, it becomes especially important to create a secure and trusting bond with the therapist, as fear, shame, and guilt are often prominent emotions. This can be achieved by validating the victim’s narrative, maintaining an open attitude, and ensuring the person feels understood and validated (Nieto Martínez & López Casares, 2016). It is noteworthy that humanistic psychotherapy focuses on the therapeutic relationship as a tool for change. However, the evidence supporting the effectiveness of this model for trauma treatment is still limited, albeit promising, highlighting the need to further examine its potential contributions to this field.

Humanistic psychotherapies claim that people naturally tend to develop their potential, and that the therapeutic space should be an environment of trust and empathy which facilitates self-exploration and encourages this development, thereby fostering the acquisition of resources to live in a more adaptive way (Cain et al., 2016). Therapies from a humanistic approach take into account the subjectivity of patients and seek to understand them from their perception of reality rather than from a diagnostic label. These therapies have a greater focus on emotions and the ‘self’, understood as self-concept, self-knowledge, and self-efficacy. Moreover, they understand the person holistically, as an indivisible organism in constant interaction with its environment (Cain et al., 2016).

One of the greatest challenges of the humanistic approach since its beginnings has been to adjust to the methodology of academic research, marked by behavioral and later cognitive-behavioal models. Humanistic psychology has opted for a research methodology that responds to the complexity and openness of human phenomena, taking into account the unique characteristics of each individual and their capacity for creativity (Polkinghorne, 1992). In this approach, therefore, qualitative or single-case research takes priority over empirical studies with large samples where all possible variables are operationalized and controlled, and whose aim is to generalize results and establish structured therapeutic protocols. This makes it difficult for certain institutions to propose humanistic procedures as treatments of first choice.

It is understood that one of the reasons why cognitive-behavioral models have a high dropout rate in the treatment of PTSD is because of a less pronounced focus on the therapeutic relationship (Yasinski et al., 2018). It is also known that one of the basic pillars of psychological intervention in humanistic therapies is the establishment of such a relationship (Cain et al., 2016). It is critical, therefore, to improve our understanding of how such therapies may contribute to the improvement of the symptomatology associated with trauma. To this end, this study conducted a systematic review of the literature aimed to explore the contributions of humanistic therapies to the psychological treatment of patients with a history of trauma. The handbook of research and practice of the humanistic approach was used to select the main therapies within this model (Cain et al., 2016), which are described below.

Objective

Like the literature reviewed above, the aim of this systematic review was to identify the different contributions made by the main humanistic models to the psychotherapeutic treatment of PTSD or symptoms associated with traumatic experiences. This could provide evidence of the efficacy of the humanistic approach in this context and thus establish the basis for more effective intervention proposals.

Method

Results

Study Selection

The selection process is displayed in the PRISMA flow diagram (Figure 1), which details the reasons for exclusion where applicable. The initial search generated 392 results from the four databases. After eliminating duplicated documents, 215 articles were left for a first screening of titles and abstracts, 150 of which were excluded. Ten of the remaining 65 articles could not be retrieved, so the remaining 55 were downloaded for full-text reading. Finally, 32 articles were discarded applying the above-mentioned inclusion criteria, and 23 articles were included for review (Figure 1).

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Figure 1.

PRISMA flow chart of the selection process.

Seventeen of the included articles were empirical studies, and six were reviews. As for the type of therapy analyzed, EFT was most frequent (n = 8), followed by GT (n = 6), PCT (n = 5), ET (n = 1), and TOF (n = 1). Some articles referred to other humanistic therapies without specifying any of the above categories (n = 3).

Discussion

The aim of this systematic review was to identify the ways in which the humanistic approach has contributed to the treatment of PTSD and symptoms associated with traumatic experiences, as a way to provide scientific evidence of its efficacy in this context. According to the results of this study, at least the main humanistic psychotherapies have proven to be useful for the treatment of PTSD and trauma-related symptoms thanks to their non-directive therapeutic style, their focus on the patient’s subjective experience, and on the therapeutic relationship as a tool for change.

In most of the empirical studies reviewed in which the reduction of PTSD symptoms after the application of humanistic psychological therapy is evaluated, this reduction was clinically significant (e.g., Anderson et al., 2010; Butollo et al., 2014; Hagl et al., 2015; Holowaty & Paivio, 2012; Paivio et al., 2010). Furthermore, the results revealed that their efficacy may be comparable to that of cognitive-behavioral treatments proposed by NICE (2018) as a first choice for treating PTSD. In the studies that compared therapies from the two models, the reduction in PTSD symptoms was significant in both groups, and no major differences in treatment efficacy were found (Butollo et al., 2016; Capaldi et al., 2016; Ghafoori et al., 2019; König et al., 2018, 2020; Zandberg et al., 2016). Patients related positively to different treatments and perceived useful elements in both therapeutic approaches (König et al., 2020). Nevertheless, some advantages of cognitive processing therapy over dialogical exposure therapy were detected in reducing traumatic cognitions (König et al., 2018), as well as a markedly greater reduction of externalizing symptoms with PET versus CPT (Zandberg et al., 2016). In contrast, advantages of dialogical exposure therapy compared with cognitive processing therapy were observed for the reduction of interpersonal problems (König et al., 2018), as well as a lower dropout rate in the CPT versus CBT and PET groups (Ghafoori et al., 2019).

While the dropout rate of papers reviewed here has ranged between 5.8% and 20% when humanistic psychotherapies are used for the treatment of PTSD or associated symptoms, a notable anomaly exists in one study, which reported a rate of 41.75% (Ghafoori et al., 2019). This impacts the range by 21.75%. The dropout rate for CBT, however, exceeded that number and reached 54.82% in the same study. This high rate of therapy dropout might be related to what has been referred to in the scientific literature as the difficulties of CBT in generating a strong therapeutic alliance (Yasinski et al., 2018). According to previous research, the dropout rate of CBT ranges from 19.9% to 28.6%, figures that are above those found when applying humanistic psychotherapy. Moreover, due to the characteristics of patients with PTSD or symptoms associated with traumatic events, the need for a bond of trust and security with the therapist in order to adhere to treatment is even greater (Nieto Martínez & López Casares, 2016). Therefore, and in light of the results of this review, humanistic psychotherapies could represent an alternative that might lead to a decrease in dropout rates, as one of the fundamental pillars of the humanistic model is the therapist-patient relationship (Cain et al., 2016). However, in one of the studies reviewed, it was observed that if the patient profile is adolescent women who have been victims of sexual assault, a greater alliance could be perceived with therapists using PET than with those employing PCT (Capaldi et al., 2016). Given these contradictory results, it is necessary to investigate whether humanistic psychotherapies are effective in generating a strong therapeutic alliance with all types of populations or, considering the scarcity of available evidence for PCT in this context, if any of these therapies are superior to others in generating a strong therapeutic relationship.

In sum, the results of this study suggest that, although humanistic therapies are often perceived as having less empirical support – potentially leading to the assumption that they are unsuitable for certain psychological problems – existing research, though comparatively limited relative to approaches that have received more attention in the academic context such as CBT, nonetheless provides additional evidence of their benefits. As Hoffman and Lac (2025) recently highlighted, existential-humanistic therapy has a solid empirical foundation, meets the standards of evidence-based practice in psychology and can be at least as effective as other therapeutic approaches.

For the purpose of compilation, the following common aspects may summarize the specific contributions of humanistic therapies to the treatment of PTSD or trauma-related symptoms.

Conclusion

Humanistic psychotherapy may contribute positively to the treatment of psychological trauma, probably thanks to the specific characteristics of this model. CBT and EMDR continue to be the psychological therapies with the strongest empirical support for treating individuals with PTSD; however, the available research examining humanistic therapies indicates promising outcomes, emphasizing that a lack of extensive evidence does not imply ineffectiveness. Moreover, a growing number of professionals acknowledge the effectiveness of humanistic psychotherapies for people with a history of trauma and are increasingly adopting this approach to better accommodate the unique needs of each patient. A humanistic framework, which emphasizes flexibility, respect for the patient’s rhythms and needs, and the creation of a safe and supportive therapeutic environment, may enhance treatment adherence, addressing the high dropout rates often observed in cognitive-behavioral approaches and potentially benefiting a larger population. Key contributions of humanistic psychotherapies for the psychological treatment of trauma-related issues as highlighted by this review include: (a) the therapeutic relationship as a vehicle for change; (b) the use of empathic dialogue; (c) an experiential focus that enables patients to identify, experience and express their emotions within the session; and (d) the application of imaginal or symbolic exposure to traumatic stimuli. Future research should aim to develop specific humanistic interventions for PTSD and empirically evaluate their efficacy. Such work would not only strengthen the evidence base for humanistic therapies but also expand their role within the scientific community and general clinical practice.

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