The ability to engage in mental time travel -- to delve back into past events or imagine future outcomes -- is a unique and central part of the human experience. And yet this very ability can have detrimental consequences for both physical and mental well-being when it becomes repetitive and uncontrolled.

A special series of articles in the July 2015 issue of Clinical Psychological Science (CPS) investigates this kind of repetitive thinking, exploring the core psychological processes that underlie maladaptive thought processes like worry and rumination. The series highlights cutting-edge research and methodology with the aim of advancing our understanding of the processes that contribute to mental health and illness.

"Our interest (as a journal) in repetitive thinking is in the role it may play in clinical dysfunction but also in mental health and physical health more generally. Apart from the role of repetitive thinking in clinical dysfunction, such thinking plays a pervasive role in everyday life and more broadly is central to the human condition," writes CPS Editor Alan Kazdin in his introduction. "This series is rich in the facets of repetitive thinking that are discussed and illustrated, including the role of rumination in dysfunction and therapeutic change."

According to special series guest editors Rudi De Raedt, Paula Hertel, and Edward Watkins, the articles collectively provide clear evidence for the advantages of taking a procedural, transdiagnostic approach to understanding repetitive thinking and other cognitive phenomena.

"Conceptualizing disorders with respect to converging patterns could stimulate the development of a new generation of interventions focused on changing the processes of disordered thought and affect," De Raedt, Hertel, and Watkins write in their introduction to the special series.

"Soon gone are the days of believing that clinical psychology can advance merely by describing people's thoughts and labeling them according to diagnostic criteria," the guest editors conclude.

Special Series: Mechanisms of Repetitive Thinking

Ruminative Thinking: Lessons Learned From Cognitive Training

Nilly Mor and Shimrit Daches

Attentional Control and Suppressing Negative Thought Intrusions in Pathological Worry

Elaine Fox, Kevin Dutton, Alan Yates, George A. Georgiou, and Elias Mouchlianitis

The Effects of Rumination Induction on Attentional Breadth for Self-Related Information

Maud Grol, Paula T. Hertel, Ernst H. W. Koster, and Rudi De Raedt

Examining the Relation Between Mood and Rumination in Remitted Depressed Individuals: A Dynamic Systems Analysis

Ernst H. W. Koster, Lin Fang, Igor Marchetti, Ulrich Ebner-Priemer, Peter Kirsch, Silke Huffziger, and Christine Kuehner

Stress-Induced Changes in Executive Control Are Associated With Depression Symptoms: Examining the Role of Rumination

Meghan E. Quinn and Jutta Joormann

Delineating the Role of Negative Verbal Thinking in Promoting Worry, Perceived Threat, and Anxiety

Colette R. Hirsch, Gemma Perman, Sarra Hayes, Claire Eagleson, and Andrew Mathews

For Ruminators, the Emotional Future Is Bound to the Emotional Past: Heightened Ruminative Disposition Is Characterized by Increased Emotional Extrapolation

Edward Watkins, Ben Grafton, Stacey Megan Weinstein, and Colin MacLeod