Positive psychology emphasizes positive traits, and happiness can come from fulfilling experiences and self-transcendence through the practice of virtues (Donaldson et al., 2014). Positive psychological traits are stable characteristics shaped by the interaction of genetic predispositions and social experiences. They include positive personality traits, adaptive self-regulation, and positive emotional experiences like hope, optimism, and gratitude. These traits are essential for happiness and serve as key resources for enhancing self-efficacy, psychological resilience, and emotional regulation (Parkinson et al., 2023; Seligman, 2011). Seligman and Csikszentmihalyi (2000) also introduced the concept of “positive personal traits,” which includes characteristics such as love and vocation, courage, and interpersonal skills, highlighting their importance for enhancing individual happiness and mental health. Seligman (2004) viewed positive psychological traits as “virtues and strengths,” and suggested that these traits may improve psychological resilience and overall well-being. Fredrickson (2001) argued that positive psychological traits are crucial for accumulating psychological resources that enhance mental health and social adaptability. Recent empirical research supports these views, showing that traits such as gratitude, bravery, perseverance, and self-regulation are significant predictors of psychological health and well-being (Kaynak, 2025; Malik et al., 2025; Sheikh and Siddiqui, 2023). Building on these points, Peterson (2004) classified positive psychological traits into six core virtues including wisdom and knowledge, courage, love and humanity, justice, temperance, spirituality and transcendence, along with 24 character strengths.

Art therapy is a therapeutic intervention that promotes mental health and emotional regulation through artistic creation. This therapy offers individuals a channel for emotional expression and self-exploration, helping them express their inner thoughts and emotions, resolve emotional conflicts, and restore psychological balance in a safe environment (Bozcuk et al., 2017). For instance, research has shown that this method can alleviate stress, reduce psychological distress, improve concentration, and enhance overall well-being (Stuckey and Nobel, 2010).

Art therapy originated in the early 20th century, when psychologists began exploring the integration of art into psychotherapy. Carl Jung established foundational practices by systematically employing artistic creation as an analytical tool. He believed that artistic creation could symbolize unconscious imagery and visualize dream content, thereby facilitating understanding of an individual’s inner world. Modern neuroscience research provides support for his view by demonstrating that artistic creation engages brain networks involved in imagination, memory, and emotion, such as the default mode network (DMN), which are associated with self-reflection and symbolic processing (Carroll, 2020; Prasad, 2022; Vaisvaser et al., 2024).

Over time, art therapy evolved into an independent discipline. Naumburg (1953) proposed that artistic creation serves as a form of symbolic communication, allowing direct expression of unconscious content. Engaging in spontaneous image creation enables individuals to experience free association, which facilitates emotional release and psychological healing. Kramer emphasized the therapeutic value of the art-making process itself, arguing that the process is more important than the final interpretation (Thompson, 2014). She introduced the concept of “art as therapy,” suggesting that through artistic creation, patients can transform unconscious conflicts into creative outcomes, thereby enhancing their mental health. In recent years, advances in neuroscience have highlighted the impact of art creation on brain activity, such as activation of the prefrontal cortex and reward systems, which enhance self-regulation and emotional control, thereby providing scientific support for art therapy (Bolwerk et al., 2014).

Thematic art drawing is a form of art therapy that uses specific themes to help individuals express and explore their inner world. It blends the flexibility of artistic expression with the focused nature of therapeutic intervention. This combination makes thematic art drawing a valuable extension of traditional art therapy within a more structured framework. The concept of thematic art drawing originates from classic projective drawing tests, such as the House-Tree-Person Test (HTP), Draw-a-Person Test (DAP), and Baum Test. These early tools were widely used in psychological assessments (Buck, 1948; Koch, 1952; Machover, 1949). Building upon this foundation, thematic art drawing has developed into a structured psychological treatment method. Its goal-directed design allows it to be an effective tool for psychological intervention and treatment.

In art therapy, thematic art drawing helps individuals address specific psychological challenges like trauma, anxiety, depression, and self-identity. Empirical research suggests that thematic art drawing enhances attentional focus, reduces internal psychological conflicts, and is more effective than free-form art in treating anxiety symptoms (Cross and Brown, 2019). Studies on chronic pain patients indicate that it helps reduce stress and negative emotions related to pain, strengthens psychological resilience, and promotes well-being (Hass-Cohen et al., 2021). Similarly, research on personality disorders shows that thematic art drawing improves self-awareness, facilitates emotional recognition, and adaptive emotional regulation strategies (Haeyen et al., 2018). For college students, projective drawing tests like the HTP are useful in identifying psychological distress and guiding targeted counseling interventions (Wang and Chen, 2018).

Thematic art drawing has exhibited significant potential in diverse populations and psychological contexts in recent years. While prior studies confirm that art-based interventions (e.g., painting) facilitate emotional regulation, coping strategies, and psychological well-being among adolescents (Bosgraaf et al., 2020; Stuckey and Nobel, 2010), empirical research on their efficacy in cultivating positive psychological traits in college students remains limited. To address this research gap, the present study introduces a structured thematic art-based intervention model known as the “Happiness Tree.”

The “Happiness Tree” is a thematic art-based drawing intervention grounded in positive psychology and art therapy. It combines symbolic imagery, creative drawing, and reflective writing to help individuals identify and reinforce psychological resources related to happiness. With over a decade of empirical validation, the model uses the tree metaphor—comprising roots, trunk, and crown—to help participants explore their emotional strengths, social support, and future aspirations. Tree imagery was chosen for its simplicity and strong associations, making it more accessible than other forms of figure drawing (Gu et al., 2020). In psychological research, trees are commonly used as projective symbols that reflect emotional and cognitive states, social connection, and personal development. Different parts of the tree represent different emotional domains or life dimensions in the HTP test (Yu et al., 2016). Similarly, within symbolic drawings, trees often represent internal resilience, vitality, and potential. The tree metaphor encourages individuals to examine their personal histories, development, and aspirations in growth-oriented and self-actualization contexts.

The model consists of three core components:

The “Happiness Tree” aims to guide individuals in identifying and reinforcing their personal happiness resources. It fosters positive emotional experiences and helps strengthen positive psychological traits. According to the Broaden-and-Build Theory (Fredrickson, 2001), positive emotions expand cognitive and emotional capacities, which enables individuals to face challenges with more flexibility. The “Happiness Tree” operates as a mechanism that empowers individuals to externalize existing happiness resources through visual and written expression, thereby reinforcing positive emotions and broadening their cognitive perspectives.

Furthermore, artistic and written expression facilitate the concretization of both internal and external psychological resources, enhancing coherence between emotional expression and self-awareness. This process supports more effective emotional regulation, allowing individuals to recognize their emotional origins more clearly and cognitively reconstruct their happiness framework.

To assess and examine the feasibility and effectiveness of the “Happiness Tree” thematic art-based drawing in fostering positive psychological traits, this study is designed as a pilot exploratory investigation and utilizes subjective well-being and general self-efficacy as key indicators. Group-based interventions are employed to assess its impact on college students. Accordingly, this study hypothesizes that participation in the “Happiness Tree” thematic art-based group counseling program will significantly enhance positive psychological traits—specifically, subjective well-being and self-efficacy—among college students.

A convenience sampling method was used to recruit participants from a public university in China and a total of 36 participants voluntarily participated in this study. Sample size was determined by practical considerations for this exploratory pilot study. No formal power calculation was conducted a priori. The results of the General Health Questionnaire (GHQ-20) (Murphy, 1973) indicated that all participants had good mental health. Participants were randomly assigned to groups using a computer-generated randomization sequence with allocation concealment. Allocation concealment was maintained until all baseline assessments were completed. Outcome data were collected by a trained student research assistant who was blinded to group assignment and not involved in the intervention process. Two participants dropped out due to inability to attend the full intervention. Ultimately, 16 participants (all female) were assigned to the experimental group, and 18 participants (2 male, 16 female) were assigned to the control group. All participants were first- or second-year students. The experimental group received six biweekly online group counseling sessions over 11 weeks, while the control group received no intervention during the study period. Two weeks after the experiment, the control group was offered a “Happiness Tree” group counseling experience. All participants gave written informed consent prior to participation. The study flow is illustrated in Figure 1.

The General Health Questionnaire (GHQ-20) was developed by Murphy (1973) and later revised into a 20-item Chinese version by Li and Kam (2002). The questionnaire includes three subscales: self-affirmation, depression, and anxiety. It uses a dichotomous (“Yes”/“No”) scoring system, where a “Yes” is scored 1 point and “No” is scored 0 points. Items 7 and 10 are reverse scored. In this study, the self-affirmation subscale scores were reverse-coded and included in the total score, where higher scores indicate poorer mental health. The internal consistency coefficient for this scale was 0.82.

The General Self-Efficacy Scale (GSES) was created by Schwarzer (1997) and translated into Chinese by Wang et al. (2001). The scale includes 10 items rated on a 4-point Likert scale, ranging from 1 (“Completely incorrect”) to 4 (“Completely correct”). Higher scores indicate higher self-efficacy. The internal consistency coefficient for this scale was 0.87.

Subjective well-being was assessed using the Satisfaction with Life Scale (SWLS) and the Positive and Negative Affect Schedule (PANAS). The SWLS, developed by Diener (2000), consisted of five items rated on a 7-point Likert scale, ranging from 1 (“Strongly Disagree”) to 7 (“Strongly Agree”). Higher scores reflect greater life satisfaction. The internal consistency coefficient for SWLS was 0.84.

The PANAS, developed by Watson et al. (1988) and revised by Qiu et al. (2008), includes 10 positive and 10 negative emotion words. Responses are rated on a 5-point scale from 1 (“None or very slight”) to 5 (“Very strong”). Higher scores indicate stronger positive or negative emotions. The internal consistency coefficient for PANAS was 0.83.

Following prior research (Liang et al., 2024), subjective well-being scores were calculated as the weighted average of life satisfaction scores, positive affect scores, and reverse-coded negative affect scores, with a weight ratio of 1.1:1:1.

The experimental group received “Happiness Tree” thematic art-based group counseling, facilitated by two certified psychological counselors from the university. The program design and implementation were supervised by a psychology expert, who was consulted at each stage of the intervention to dynamically adjust counseling strategies and ensure the sessions’ effectiveness. The counseling program was theoretically grounded in positive psychology and designed based on the Balint group structure. It comprised six sessions, delivered in two smaller subgroups due to the large number of participants. Each facilitator led 8–9 members per group, and each session lasted 70–90 min. In each group session, each participant created a “Happiness Tree” drawing. One or two members shared their artwork, followed by group discussions on their experiences. Finally, the two subgroups merged into a larger group for collective reflection and experience sharing. To further ensure fidelity, the program followed a pre-defined structure and was implemented consistently across all sessions (see Table 1). Periodic consultations with the supervising expert helped address challenges encountered and supported adherence to the intervention protocol.

The counseling program was structured into three phases:

Phase 1 (session 1): group formation

All group counseling sessions were conducted online. The detailed implementation process and participant tasks are summarized. The study involving human participants was reviewed and approved by the Department of Scientific Research and Teaching Affairs, Hefei Preschool Education College (approval date: April 26, 2023). Informed consent to participate in the study was provided to all participants.

Data were analyzed using SPSS version 24.0. All analyses followed the intention-to-treat (ITT) principle to preserve the benefits of randomization. For participants who discontinued the intervention after attending the first session and did not complete post-test assessments (n = 2 in the experimental group), missing data were imputed using the last-observation-carried-forward (LOCF) method. Continuous data were presented as median (Md) and interquartile range (IQR), as indicated in the tables. The Mann–Whitney U Test was employed to assess the homogeneity between the experimental and control groups, as well as to compare pre- and post-counseling differences. The Wilcoxon Signed-Rank Test was applied for within-group comparisons. Non-parametric effect sizes were expressed as rank-biserial correlations (r), with confidence intervals calculated using bootstrapping procedures in JASP version 19.3. Statistical significance was set at a p-value of less than 0.05.

The Mann–Whitney U Test was performed to examine pre-test differences between the experimental and control groups. The results revealed no significant differences between the groups regarding mental health, subjective well-being, and general self-efficacy scores. These findings suggest that the two groups were homogeneous prior to the group counseling, thus validating the initial grouping based on positive psychological traits and justifying the continuation of the study (Table 2).

The Wilcoxon Signed-Rank Test was employed to compare pre- and post-test scores within the two groups. The results indicated a statistically significant increase in subjective well-being scores in the experimental group post-counseling compared to pre-counseling (Z = 116.000, p < 0.05). No significant changes were observed within the control group or in the experimental group’s scores for general self-efficacy, either pre- or post-counseling (Table 3).

The Mann–Whitney U Test was utilized to compare the differences in pre- and post-test scores between the experimental and control groups. The results revealed that the experimental group exhibited significantly higher score differences in subjective well-being and general self-efficacy compared to the control group, with both differences reaching statistical significance (U subjective well-being = 78.500, U general self-efficacy = 80.000, both p < 0.05). In terms of effect sizes, the intervention yielded moderate effects on both subjective well-being (r = 0.404, 95% CI [0.046, 0.670] and general self-efficacy [r = 0.426, 95% CI (0.072, 0.684; Table 4)]. These effect sizes should be interpreted cautiously given small sample size and wide confidence intervals.