Even in cases with complexity, simple techniques can be useful to target a specific symptom. Intrusive mental images are highly disruptive, drive emotion, and contribute to maintaining psychopathology. Cognitive science suggests that we might target intrusive images using competing tasks.

We describe an imagery competing task technique within cognitive behavioural therapy (CBT) with a patient with bipolar disorder and post-traumatic stress disorder (PTSD) symptoms. The intervention – including Tetris computer game-play – was used (1) to target a specific image within one therapy session, and (2) to manage multiple images in daily life.

A single case (AB) design was used. (1) To target a specific image, the patient brought the image to mind and, after mental rotation instructions and game-play practice, played Tetris for 10 minutes. Outcomes, pre- and post-technique, were: vividness/distress ratings when the image was brought to mind; reported intrusion frequency over a week. (2) To manage multiple images, the patient used the intervention after an intrusive image occurred. Outcomes were weekly measures of: (a) imagery characteristics; (b) symptoms of PTSD, anxiety, depression and mania.

(1) For the target image, there were reductions in vividness (80% to 40%), distress (70% to 0%), and intrusion frequency (daily to twice/week). (2) For multiple images, there were reductions from baseline to follow-up in (a) imagery vividness (38%), realness (66%) and compellingness (23%), and (b) PTSD symptoms (Impact of Events Scale-Revised score 26.33 to 4.83).

This low-intensity intervention aiming to directly target intrusive mental imagery may offer an additional, complementary tool in CBT.