The mechanisms of psychiatric dysfunction in PTSD have been linked to fear conditioning (Johnson et al., 2012) with dysfunction in extinction processes and safety learning–leading to the reinforcement and preservation of PTSD (VanElzakker et al., 2014). There are several co-morbidities which may prolong and exacerbate recovery including substance use, TBI, and sleep disturbance (Short et al., 2017; Bottari et al., 2023). These co-morbidities can lead to disruptions in memory consolidation, engagement with psychotherapy, and treatment compliance, hindering remission of PTSD (Stickgold and Walker, 2007). PTSD is a learned response that is reinforced behaviorally as a self-preservation mechanism. These survival responses may be protective during active danger. Unfortunately, their persistence is maladaptive in non-threatening contexts. PTSD changes over time and may resolve on its own. However, it is also quite responsive to psychotherapy. Recommended treatments for PTSD include exposure-related psychotherapy and pharmacological intervention (e.g., SSRIs) (Williamson et al., 2021). While psychotherapy has proven to be effective for PTSD (g = 1.14; Watts et al., 2013), there are significant rates of dropout (up to 18.28%) for trauma-focused PTSD treatment (Imel et al., 2013). Moreover, many people who complete treatment continue to have clinically significant symptoms of PTSD as well as recurrence. Sleep disruptions often persist even with clinically significant response to psychotherapy (Bottari et al., 2023). Elevated dropout rates are often attributed to the trauma component of most psychotherapies causing distress and discomfort. The American Psychological Association (APA) and Veterans Affairs (VA) recommend trauma-focused cognitive behavioral therapy (CBT-TF) or Prolonged Exposure Therapy (PE) as the gold standard of treatment, with additional psychotherapies indicated as potential options for PTSD treatment such as eye movement desensitization and reprocessing (EMDR) (American Psychological Association, 2020; Norman et al., 2023). Suggested pharmacological interventions are like those recommended for anxiety and depression and include, but are not limited to, SSRIs (i.e., fluoxetine, paroxetine, sertraline) and serotonin and norepinephrine reuptake inhibitors (SNRIs) like venlafaxine. Stigma surrounding mental health diagnoses is prevalent in military populations (Mittal et al., 2013; National Academies of Sciences & Medicine, 2018), and multiple studies have found low evidence-based psychotherapy engagement at 11.4% of Veterans referred (Mott et al., 2014) and higher dropout rates among Veterans with PTSD than randomized control trials (RCT) for PTSD in civilians (Zayfert et al., 2005; Schottenbauer et al., 2008).

Given the lack of engagement with empirically supported psychotherapies, high dropout rates, common incomplete remission of PTSD post-treatment, and heterogeneity of responses to treatment, other interventions are necessary. Art therapy is currently used in the Veterans Health Administrations system of care to treat PTSD. Though empirical support is limited through RCTs, art therapy has been used in a range of military populations with reported benefit (Campbell et al., 2016; Walker et al., 2016, 2017; Levy et al., 2018; Jones et al., 2019; DeLucia and Kennedy, 2021; Schnitzer et al., 2021). Art therapy allows for active creative self-expression that integrates non-verbal communication through visual narratives (Berberian et al., 2019). Service to military populations is at the core of art therapy, which developed from treatments for “battle fatigue” (a term that preceded PTSD), in World War II (Howie, 2017) and since has been a part of integrative and primary psychotherapy for patients with TBI and PTSD. Since trauma may be encoded through visual images, sounds and smells, art therapy may be a modality consistent with sensory encoding of traumatic events. Service members and Veterans identify, externalize, and process their psychological difficulties through art therapy, actively engaging the creative process within a psychotherapeutic relationship facilitated by a credentialed art therapist (Campbell et al., 2016; Walker et al., 2016; Kaimal et al., 2018; Berberian et al., 2019). Military service members and Veterans with PTSD and history of TBI report that art therapy enabled them to gain a sense of integrated identity (Walker et al., 2016), self-regulation (Jones et al., 2018), and access to previously blocked memories and insight (Campbell et al., 2016) suggesting successful fear extinction associated with completing art therapy.

Art therapy has demonstrated positive health outcomes in case studies, observational research, and program evaluation studies with military population with TBI and PTSD (Jones et al., 2018; Kaimal et al., 2018). However, despite decades of use and demonstrated positive impacts on specific outcome measures, including anxiety and depression (Abbing et al., 2018; Dunphy et al., 2019; Kaimal et al., 2019), implementation of art therapy is hindered by the lack of rigorous, well-controlled trials that investigate both effectiveness and neurobiological mechanisms of improvement. This conceptual paper aimed to inform the neurophysiological rationale in the use of art therapy as a therapeutic approach for individuals with PTSD. This is accomplished through a conceptual integration of art therapy change factors, comparison of art therapy change-factors to existing standardized treatments for PTSD, and neurophysiological effects.

A narrative synthesis method (Edwards and Kaimal, 2016) was used to identify and conceptualize the role of art therapy for PTSD (Figure 1). After search and selection, each art therapy research study was coded for study characteristics identifying study purpose, design, setting, population, intervention, targeted outcomes, and main findings in subgroups of neurophysiological markers such as art therapy and MRI, fNIRS, EEG, HRV, and other biomarkers. Next, the findings on active factors of change for art therapy by de Witte et al. (2021) were considered to identify art therapy processes (common, joint, or specific) such as concretization, symbolism and metaphors, active engagement, artistic pleasure, tactile quality of art, non-verbal expression, modulating time and space, perspective taking, emotion processing and regulation, and therapeutic alliance. We then considered the empirical clusters of therapeutic factors to map on each of the neurophysiological study on art therapy, to find associations in therapeutic factors, neurophysiological effects or outcomes.

To offer a broader perspective on the relationship between therapeutic factors, the team conducted inductive analysis via debriefings and analytical discussions, leading to the identification of five factors relevant to PTSD symptomatology. Considering the small pool of neurophysiological studies in art therapy, findings from empirical neuroaesthetics were reviewed to bolster support in identifying mechanisms and neural bases of visual art engagement based on the five categorized art therapy factors. While these factors are theoretical and potentially interact, they represent a useful framework for developing a structured approach to art therapy. Neuroaesthetics is useful in that this area of work is designed to determine the cognitive and neural basis of art and aesthetic experiences. The known roles of aesthetic engagement in brain function and change may be relevant to mechanisms of art therapy responses in mental health populations. Others have posited these mechanisms in the clarification of intervention strategies and clinical applications of art therapy (King and Parada, 2021). We reviewed studies on creative cognition, and the impact of visual art engagement/production on brain function. We used backward and forward citation searching of the reference lists to supplement supporting evidence. Based on the mechanisms of change in art therapy (de Witte et al., 2021) and the mechanisms reported in empirical studies on art therapy and esthetics, we discuss five art therapy factors and their relevance for treatment of PTSD symptoms. Following this step, the neurophysiological evidence of standard psychotherapies for PTSD as recommended by VA were sought through research papers and user guides for PTSD for psychotherapies to summarize their relation to the five art therapy factors, and to identify similarities/gaps in comparison to art therapy. The selections for creative cognition, neuroaesthetics, and empirical psychotherapy literature were based on their conceptual and analytic association with art therapy factors.

The principal objective of the conceptual review was to formulate a theoretical foundation research on the function of art therapy. Given the limited content available within the domain of art therapy, supplementary resources from neurophysiological evaluations of psychotherapies and neuroaesthetics research with similar components to art therapy were incorporated to enrich and establish the proposed framework. In the final step, art therapy factors and empirical neuroaesthetics findings were integrated onto the triple network model of PTSD -the altered dynamic between and within the DMN, CEN, and SEN (Akiki et al., 2017). While, there is a broader research base on task dependent change in brain networks (e.g., fronto-limbic networks) in PTSD, the three resting state networks were chosen as they are the most commonly reported fMRI approach found in the literature. This paper provides a conceptual review and outlines future research implications for understanding and investigating the impact of art therapy on PTSD. It achieves this by synthesizing existing literature and proposing ways in which art therapy, informed by neuroscience, could potentially foster resetting adaptive responses to danger and life-threat among individuals with PTSD.

In a scoping review on mechanisms of therapeutic change of creative arts therapies, de Witte et al. (2021) found that the use of symbolism and metaphors, and concrete representation of abstract content into tangible form are unique factors to creative arts therapies. Specifically, art therapy involves expression and processing of thoughts, emotions, and ideas through imagery onto a concrete visual form. These may emerge as representational artwork, as symbols or metaphors where one thing is conceived in terms of another to understand abstract, emotional, or other experiences (Lakoff and Johnson, 2008). The creative process of using metaphors and symbols allows new insights into the self, others, thoughts, feelings, and situations (Kaimal, 2022). Military populations with PTSD and TBI have reported benefit of art therapy to communicate inner experiences or visual self-narratives on artworks-metaphorically or symbolically (Smith, 2016; Walker et al., 2017; Schnitzer et al., 2021).

An empirical neuroaesthetics study indicates that “metaphor production involves brain systems important in executive control, semantic integration, and self-generated thought” (Beaty et al., 2017, p. 163). Studies on creative cognition indicate dynamic interaction between brain regions associated with executive control and spontaneous thought (Mayseless et al., 2015; Bashwiner et al., 2016; Zabelina and Andrews-Hanna, 2016; Beaty et al., 2017). The studies on metaphor production have been focused on linguistic metaphors, and further evidence on connection between artmaking and spontaneous visual metaphor production during art therapy could be important in understanding potential therapeutic impact of these methods.

Actively engaging in artmaking through the choice of varied art media is a specific and unique aspect of art therapy (de Witte et al., 2021). Art therapy facilitates engagement through the physicality of various art materials on a continuum- from structured art media like markers and colored pencils to fluid art media like pastels and paints (expressive therapies continuum, ETC) (Hinz, 2019). Since visual artmaking and imagery are integral parts of art therapy, the visual and perceptual systems of the brain are recruited (King et al., 2019). The tactile and sensory quality of visual art media (Abbing et al., 2018) and the choice of appropriate and specific art materials (Haeyen et al., 2015; Bosgraaf et al., 2020) may contribute to a shift from maladaptive to adaptive responses for clients. This aligns with the framework of adaptive response theory which situates artmaking and the art product as distinct elements in the therapeutic process (Kaimal, 2019).

Art therapy also involves active kinesthetic components that can “induce haptic, proprioceptive, and visual sensations” (Nan et al., 2021). An experimental study examined EEG activity of 14 healthy participants during clay sculpting and drawing recorded over bilateral medial frontal cortex and bilateral medial parietal cortex of each participant (Kruk et al., 2014). Clay sculpting increased gamma power over the right medial parietal lobe and increased theta power over the right frontal lobe. Although a small sample size, these preliminary results suggest impacts of engagement in sculpting on brain regions important in emotional regulation and spatial processing. Other neurophysiological studies on artmaking have also found differences in EEG measurements with significant pre and post drawing differences in the left posterior temporal, parietal, and occipital regions within the alpha band frequency when artists participants used oil pastels (Belkofer et al., 2014). In another study participant’s use of chalk pastels also showed a general increase across all frequencies, with a statistically significant increase in the left hemisphere (King et al., 2017). In patients with Parkinson’s disease (PD) who received twenty sessions of art therapy, there was an improvement in overall visual-cognitive skills and visual exploration strategies as well as general motor function as seen through decreases in visual exploration path length, horizontal fixation variance, and in the number of saccades made during the Benton Visual Recognition Test (Cucca et al., 2021). The participants also showed resting state functional connectivity (fMRI) differences in visual networks (Cucca et al., 2021).

Art therapy involves projection and expression of emotions that can provide therapeutic insights necessary for facilitating treatment goals. In art therapy, the clients see their emotions through the artwork via visual elicitation of past, current, or future states and feelings (Haeyen et al., 2015; Hilbuch et al., 2016; Bosgraaf et al., 2020). Clients in military settings have found art therapy to facilitate trauma recall, increase access to emotions, and enhance representation of self in relation to individual personhood, relationships, community, or society (Campbell et al., 2016; Smith, 2016; Walker et al., 2016, 2017; Lobban and Murphy, 2019).

Art therapists are starting to examine neurobiological mechanisms involved in emotion processing to inform clinical outcomes in art therapy (Czamanski-Cohen et al., 2019). In an ongoing study, Czamanski-Cohen et al. (2020) are examining the mechanisms of art therapy on emotion processing and cholinergic anti-inflammatory processes through a RCT with breast cancer survivors. Haiblum-Itskovitch et al. (2018) examined vagal activity and emotional response to the use of different art materials/mediums. They used the self-assessment manikin visual analog scale (SAM) (Bradley and Lang, 1994) and assessed parasympathetic nervous system (PNS) function via respiratory sinus arrhythmia (RSA). Results indicated an interaction between material and state with a decrease in mean RSA from resting state while painting [F(1, 49) = 26.155, p < 0.0005], suggesting significant cognitive, emotional, and physical engagement in the process. The effect size (n_p² = 0.348) indicated that artmaking explained approximately 35% of the variability in parasympathetic reactivity, regardless of art material, indicating changes in emotional regulation processes during the artmaking task. Abbing et al. (2019) assessed anxiety following artmaking with 47 adult women with anxiety disorders with a pre-post RCT (waitlist control group) design using high frequency heart rate variability (HF-HRV, i.e., RSA) via Root Mean Squared Successive Difference (RMSSD) scores. The intervention group showed higher HF-HRV after treatment, consistent with lower anxiety. Art therapy and artmaking may reduce cortisol levels (Visnola et al., 2010; Kaimal et al., 2016; Beerse et al., 2019, 2020) that may improve other psychosocial outcomes of mood, self-efficacy, and perceived stress (Kaimal and Ray, 2017; Beerse et al., 2019). Other preliminary studies have explored blood pressure as a biomarker to examine artmaking as an effective stress reducer (Schrade et al., 2011; Utami et al., 2021). Futterman Collier et al. (2016) found that textile arts have a mood enhancing effect when measured using salivary levels of IL-beta, a proinflammatory cytokine. Overall, there is growing evidence of art making effects on autonomic features and indicators of stress that suggest relevance to positive response in PTSD.

The prefrontal cerebral cortex plays a central role in self-regulation, specifically for reward (e.g., striatum) and emotion (e.g., amygdala) (Kelley et al., 2019). In examining the regulatory effect of drawing on negative emotions, Yan et al. (2021) used autobiographical recall, and randomly assigned 59 participants to one of four conditions- drawing after triggering anger, drawing after triggering sadness, calculating numbers after triggering anger, or calculating numbers after triggering sadness. When drawing regulated sadness, the frontopolar area and left dorsolateral prefrontal cortex (dlPFC) showed significant deactivations on fNIRS, more than its effect on anger. Another fNIRS study gave 26 participants (artists and non-artists) three drawing tasks (coloring, doodling, and free drawing) and noted that all three tasks activated the medial prefrontal cortex in comparison to rest condition irrespective of the skill level, indicating implications for visual art stimulating reward perception (Kaimal et al., 2017). A study on artmaking in virtual reality (VR) (rote tracing and creative self-expression conditions) measured prefrontal cortex (PFC) activation and found that the rote tracing task resulted in higher PFC activity suggesting the potential benefits of creative self-expression in reducing conscious control (Kaimal et al., 2022).

These neurophysiological studies indicate the emerging support for visual artistic practices to facilitate alterations in neural pathways through emotion processing and regulation, and positive emotional experiences that may be a necessary mechanism for recovery for clients with PTSD.

The concrete representation of internal experiences facilitates perspective-taking and reflection (Deboys et al., 2016; Gabel and Robb, 2017; Abbing et al., 2018; Czamanski-Cohen et al., 2019; Bosgraaf et al., 2020). Art therapy can promote perspective-taking and self-awareness through reflection upon art and via artmaking during sessions (de Witte et al., 2021). Perspective-taking and reframing can occur through clarifying feelings and thoughts; exploring least to most anxiety-provoking situations/feelings/thoughts through art (Rosal, 2022); representing a problematic schema, personal constructs or exploring self-efficacy cognitions (Rosal, 2022) or “mastery images” (Morris, 2014, p. 350); and changing distressing images, symptoms or memories that interfere with functioning (Sarid et al., 2017). There is heterogeneity in the use of art therapy for example, the use of mindfulness-based art therapy is prominent (MBAT) (Rosal, 2022). Indeed, mindfulness-based stress reduction (MBSR) which include relaxation, self-management, exposure, cognitive change, and acceptance as core mechanisms (Baer, 2003) when integrated with art therapy has shown positive outcomes for pain management (Czamanski-Cohen et al., 2014; Fritsche, 2014), for oncology patients (Monti et al., 2006), for individuals with anxiety disorders (Sarid et al., 2017) and severe and persistent mental illness (SPMI) in outpatient treatment settings (Herring, 2014).

As an example of art therapy aiding an individual with PTSD to concretely express distress in art, an active-duty military service member externalized the heightened visual and tactile memories of a flashback personified as a “bloody face in bunker” (BFIB) in a mask and physically contained it in a box to overcome the debilitating intrusive traumatic images (Walker et al., 2016). Studies on art therapy and cognitive flexibility are sparse. However, Walker et al. (2018) who used fMRI to assess thalamic connectivity of Veterans suggested further research using- pre-and post-intervention to examine differences. An MBAT study found significant reductions in anxiety and perceived stress, accompanied by a reduction in salivary cortisol in a group of college students in comparison to the control group (Beerse et al., 2020). Furthermore, empirical esthetics researchers propose testing the hypothesis of aesthetic cognitivism- i.e., how art promotes knowledge and understanding (Christensen et al., 2023). Future mechanism-based intervention studies will benefit from further examination of neural correlates of perspective-taking as it relates to art therapy and PTSD symptoms.

The profession of art therapy is characterized by active artmaking and the creative process within the psychotherapeutic relationship with an art therapist (American Art Therapy Association, 2017). The positive patient-therapist relationship or therapeutic alliance is a commonly researched factor of therapeutic change (de Witte et al., 2021), with safety of environment and opportunity for emotional release as essential components. Strong therapeutic alliance has been found to be effective and has been a suggested mechanism in art therapy (Bosgraaf et al., 2020; Keidar et al., 2020). Bosgraaf et al. (2020) indicated three patterns of therapist behavior that related to psychosocial outcomes. These were: non-directive therapist behavior where the therapists showed mainly a following-and-facilitating-attitude toward the clients; directive behavior where the therapist showed an active and leading role; and a mix of these two types (eclectic). These three categories were then mapped on to outcomes of internalizing problems, externalizing problems, and social problems in children and adolescents. However, no neurophysiological studies examining therapeutic alliance in art therapy research were identified.

Default mode network (DMN) is responsible for cognitive processes that occur at rest such as introspection and self-referential thought (Akiki et al., 2017). Structurally, this network is comprised of central areas within the posterior cingulate cortex (PCC), ventromedial prefrontal cortex (vmPFC), and the medial temporal lobe (MTP, including the hippocampus) (Buckner et al., 2008). Decreased connectivity within the DMN is found in numerous psychiatric disorders including PTSD (Bluhm et al., 2009; Daniels et al., 2011; Tursich et al., 2015). It is not known why DMN connectivity is lower in PTSD, however, it is possible that patients with PTSD are less able to relax and this resting state network weakness may reflect this inability. Further, following a Criterion A event there may be disruption of network functions responsible for cognitive reappraisal [lateral orbitofrontal cortex (lOFC) to medial prefrontal cortex (mPFC)] (Akiki et al., 2018) likely leading to symptoms such as negative thoughts and misattribution. According to Mitchell et al. (2005, 2006) and Heatherton et al. (2006), chronic negative thoughts in PTSD are perpetuated by dysfunction in the mPFC which is responsible for assessing personal significance and self-judgement. The mPFC is a component of the DMN and thus people experiencing this symptom may have an associated reduction in DMN connectivity.

Psychotherapies that have longitudinally resulted in increases in DMN and CEN connectivity are CPT (Vuper et al., 2021), PE (Helpman et al., 2016; Fonzo et al., 2017; Zhu et al., 2018), and mindfulness-based exposure therapy (King et al., 2016). Increased CEN and DMN connectivity in the context of hypoactivity from PTSD suggests a therapeutic effect consistent with adaptive change in these systems (Vuper et al., 2021). Thus, these easy to acquire and quantify resting state networks are both related to symptom presentation and are responsive to successful therapeutic intervention.

Another resting state network is the SEN. Hyperarousal symptoms are related to increased activity in SEN at rest. Thus, in PTSD it may be that there is reduced DMN and increased SEN in patients with currently significant symptoms of PTSD. The SEN includes the amygdala, anterior insula (AI), and dorsal anterior cingulate cortex (dACC) (Geng et al., 2016), key structures involved in fear processing and autonomic regulation. Increases in SEN, is associated with lowered threshold of perceived salience leading to inefficient modulation of the DMN-CEN, resulting in network-wide dysfunction between the three networks (Akiki et al., 2017). DMN-SEN coupling dysfunction could lead to greater hyperarousal symptoms (Menon, 2011; Akiki et al., 2017) and is associated with sleep disturbance, elevating risk for intrusive (Dietch et al., 2019) and avoidance (Short et al., 2017) symptoms.

The third commonly cited resting state network is the CEN. The CEN allows for cognitive control over emotions and is engaged during effortful cognitive tasks (Menon, 2011). In PTSD, the CEN (anatomically the dlPFC and lateral posterior parietal cortex) shows decreased activity and associated network connectivity which then potentiates disruption of the SEN’s top-down regulation (Seeley et al., 2007; Akiki et al., 2017). The resulting SEN dysfunction leads to a poorly modulated network leading people with PTSD to experience symptoms of hyperarousal and cognitive deficits characterized by executive dysfunction. Indeed, commonly found cognitive deficits of people with PTSD are in selective attention, response inhibition, and memory (Akiki et al., 2017; Dossi et al., 2020).

Within the resting state brain networks (DMN, CEN, and SEN), there are structural brain differences seen in individuals with PTSD. It remains unclear why structural differences in the prefrontal cortex and limbic brain volumes are seen in people with PTSD (Bae et al., 2020), but it is possible that these differences are due to persistent stress signaling in the body and or abnormalities in these brain regions predisposing people to develop PTSD. Causality is unclear. Further, white matter structures connecting these regions also show differences in people with PTSD and anxiety disorders, with reductions in white matter integrity demonstrated in the uncinate fasciculus, a key fronto-limbic pathway (Costanzo et al., 2016; Tromp et al., 2019), which also appears to be associated with greater expression of sleep problems in patients with PTSD and mild TBI (Bottari et al., 2021). While reductions in white matter integrity may reflect damage, increases in structural quality measured with DTI have been shown to relate to the learning of new skills. Increases in fractional anisotropy associated with learning have been captured in as little as six weeks or as long as nine months (Scholz et al., 2009; Schlegel et al., 2012). Schlegel et al. (2015) found that training in art skills such as creative cognition, perception, and perception-to-action lead to reorganization of prefrontal white matter. Neuroplastic mechanisms of art therapy and art therapy related cognitive gains have been demonstrated in fMRI study with patients with dementia showing increased cortical thickness in the art therapy group, relative to controls which positively and significantly correlated with enhanced immediate memory (Yu et al., 2021). These preliminary studies provide evidence of potential long term neural structure alteration of prefrontal regions involved in the development and maintenance of PTSD symptomology that need to be researched and documented.