Tree Imagery in Drawing Tests for Screening Mental Disorders: A Systematic Review and Meta-Analysis

Clinical Snapshot

Key Findings

• P Value: All 24 reported characteristics reached p < 0.05

• Effect Size: ORs ranged from 2.01 (blackened tree) to 7.07 (simplified drawing) across the five categories; subgroup ORs: blackened tree OR = 1.71 (affective disorders), no motion OR = 3.34 (affective disorders), excessive separation OR = 2.77 (affective disorders), roots OR = 4.89 (thought disorders)

• Primary Outcome: Predictive efficacy of specific tree imagery characteristics for mental disorders, expressed as pooled odds ratios across five feature categories

• Nnt Or Sensitivity: Sensitivity, specificity, positive/negative likelihood ratios, and AUC not reported; NNT not applicable to this diagnostic screening context without these metrics

• Confidence Interval: Not reported in the abstract

Clinical Application

Tree drawing tests are low-cost, non-invasive, and require minimal equipment, making them feasible in resource-limited or primary care settings. However, standardised scoring requires trained clinicians, and inter-rater reliability data are not provided in this review. Implementation as a standalone screening tool is not supported by the current evidence base; adjunctive use alongside validated instruments is more appropriate. In Australia, projective drawing tests are not currently endorsed by the RACGP for routine mental health screening in primary care, nor are they listed as recommended assessment tools in the Australian Mental Health Care Classification or Better Access guidelines. The MBS does not specifically fund projective drawing assessment as a standalone item. However, these tools may have niche utility in culturally and linguistically diverse (CALD) populations, Aboriginal and Torres Strait Islander communities where culturally safe, non-verbal assessment approaches are valued, or in paediatric and forensic psychology contexts. TGA registration is not applicable to psychological assessment instruments. Clinicians considering use of tree drawing tests should be aware that Australian clinical psychology training standards require demonstrated competency in projective test administration and interpretation. The cultural validity of Chinese-derived scoring norms for Australian populations has not been established. Adults and potentially adolescents undergoing mental health screening in clinical or community settings; most applicable where verbal assessment is limited (e.g., language barriers, intellectual disability, acute psychosis, cross-cultural contexts)

Abstract

Although tree imagery in projective drawing tests is a promising nonverbal tool for screening mental disorders, its clinical utility remains constrained by inconsistent predictor selection. To address this gap, the present systematic review and meta-analysis synthesizes the characteristics of tree imagery linked to mental disorders and evaluates their predictive efficacy. Following the PRISMA guidelines, we analyzed 42 studies involving 8552 participants from English and Chinese databases published between 1948 and 2024. The results showed that 24 specific characteristics significantly predicted mental disorders (p < 0.05), which were classified into five distinct categories: blackened out (e.g., blackened tree, odds ratio [OR] = 2.01), scribbled lines (e.g., weak lines, OR = 2.82), oddly shaped (e.g., flattened crown, OR = 3.10), no vitality (e.g., very small tree, OR = 3.93), and overly simple (e.g., simplified drawing, OR = 7.07). Furthermore, subgroup analyses indicated that features such as "blackened tree" (OR = 1.71), "no motion" (OR = 3.34), and "excessive separation" (OR = 2.77) were significantly associated with affective disorders, whereas the presence of "roots" (OR = 4.89) was uniquely associated with the thought-disorder subgroup. Ultimately, tree imagery may offer a valuable nonverbal, adjunctive approach to screening for mental disorders, offering several statistically supported indicators that may effectively complement traditional assessment tools.

References

1. 1.Guo, H., Feng, B., Liu, T., Zhao, R., Fan, H., Dong, Z., Gong, Q., & Chen, T. (2026). Tree imagery in drawing tests for screening mental disorders: A systematic review and meta-analysis. Depression and Anxiety. https://doi.org/10.1037/h0026011