I love psychology, but physical therapy has a psychology problem.

I’ve already written about how the physical therapy profession should be more willing to embrace psychological research. There are some good explanations of why PTs are slow to adapt their practices to the biopsychosocial model. Many psychological interventions are poorly described, poorly implemented, and even poorly supported by evidence. Still, there is evidence to suggest that the psychosocial aspect of pain is more important than muscle physiology in predicting chronic pain. To me, ignoring the psychological element of physical therapy is just plain backwards. To others, we talk too much amount psychology.

The pendulum swings far and swings often with this topic in physical therapy. This isn’t surprising, considering the inconsistent research findings and the philosophical extremes about the role of psychology in physical therapy. One recent publication from Mary O’Keeffe et al. (2016) highlights the inconsistencies in this research, and the paper leaves me wondering where the pendulum will swing next. (By the way, Dr. O’Keeffe is on Twitter.)

O’Keeffe et al. completed a systematic review and meta-analysis comparing physical interventions, behavioral/psychological interventions, and interventions that combine physical and psychological strategies. The authors reviewed 24 randomized controlled trials that investigated differences in treatment effects for nonspecific chronic spinal pain. The “physical” interventions included TENS, ultrasound, stretching, exercise, motor control exercise, manipulation, and massage, while “psychological” interventions included breath therapy, relaxation therapy, and cognitive-behavioral therapy.

Most trials in the review compared physical interventions to combined approaches, with most studies finding no significant differences between groups. Only four of the studies found significant differences in both pain and disability, favoring combined approaches (Friedrich et al., 1998; Friedrich et al., 2005; Kankaanpaa et al., 1999; Sahin et al., 2011). The authors’ meta-analysis yielded statistically significant differences for both pain and disability between groups at short-term and a statistically significant difference for long-term follow-up in disability.

O’Keeffe et al. conclude that combining physical and psychological treatments appear to offer “only a small additional benefit” (p. 12). The authors recommend that physical therapists consider the time and resources necessary to provide combined interventions in order to choose the most cost-effective option.

If there really is a strong psychosocial component of nonspecific chronic pain, then this paper is puzzling. Why aren’t psychological treatments more effective than purely physical ones? As far as explanations for the lack of differences between groups, O’Keeffe et al. offer four possible reasons:

  1. Both physical and psychological treatments may involve a shared mechanism. For example, perhaps both exercise and cognitive-behavioral therapy lead to decreased fear of movement and improved self-efficacy, which thereby lead to reduced pain and disability.
  2. “Nonspecific factors” such as therapeutic alliance, patients’ expectations, and patients’ treatment preferences may drive progress in therapy, regardless of the type of intervention.
  3. The RCTs might not have been appropriately designed. O’Keeffe et al. note that even some “combined” approaches did not even discuss with patients the importance of sleep and life stress.
  4. The RCTs may not have tailored treatments to the needs of patients.

All four of these reasons are not only plausible, but also supported by evidence. The fourth reason deserves particular attention, in my opinion. O’Keeffe et al. refer to a large RCT that categorized patients with low back pain into different “risk” profiles (Hill et al., 2011).  Hill et al. found that some patients may be more likely to benefit from psychological intervention if they are in the “high risk” category, which is characterized by psychosocial elements of pain (e.g., pain catastrophizing, fear of movement).

This presents an interesting direction for psychologically-informed physical therapy practice. If there is a meaningful way to predict which patients will benefit from a psychological intervention, then PTs who are uncomfortable with psychological techniques could effectively screen “high risk” patients and refer them to the appropriate professionals who are comfortable with those techniques. What is more, PTs who prefer to incorporate psychological treatments in their practice could identify patients who are most likely to benefit from those treatments.

Recent research about this type of stratified care is promising. In an upcoming post, I’ll spend more time on how the STarT Back Screening Tool is a compelling way for physical therapists to stratify care.