the Diagnostic Drawing Series
Barry M. Cohen and Anne Mills
Therefore the tree is the image of our condition.
Andreas Alciatus, 1538
According to artist Paul Klee, "Art does not render what is visible; it renders visible." Although he was not referring to the use of drawings in psychological assessment, Klee's comment is nonetheless apt in a clinical context. For the severely traumatized dissociative client, making art to communicate thoughts, experiences and self-perceptions is not only functionally beneficial, but cognitively necessary. This is because traumatic experiences are so disruptive that they are unlikely to be transferred to memory in lexical terms ( Horowitz 1970) and must be stored as sensory or iconic schemas. Such schemas are typically inflexible and remain unavailable to the adult client in verbal therapy. For this reason, art provides a schema-based process by which severely traumatized clients can render these inner experiences visible isomorphically ( Cohen 1996).
Isomorphism is the central concept in the psychology of art and the expressive arts therapies. It refers to the similarity in structure between a person's internal state and its outward expression ( Arnheim 1974). Isomorphism allows clients to externalize deeply personal experiences or sensations through the strategies and styles in their art, conveyed by lines, shapes and colors ( Cohen and Cox 1995). It is isomorphism as well that allows