by Professor Dame Til Wykes, Professor of Clinical Psychology & Rehabilitation and Founder of CIRCuiTS™
The first descriptions of schizophrenia a 100 or so years ago included cognitive difficulties. We were reminded again 50 years later from interviews with people with a diagnosis of schizophrenia in long-stay hospitals (1). The cognitive themes uncovered from those interviews were about memory, attention, and concentration. But despite knowing that these difficulties existed, we were not optimistic about them being possible to change. This had some basis - if we compared different groups at different times since onset or even the same people over time, we discovered the cognitive difficulties rarely change. Nothing much seemed to change. Forty years ago, a new stress vulnerability model proposed that these cognitive factors were vulnerability markers for schizophrenia that interacted with stress to precipitate an episode of schizophrenia (2).
This vulnerability-stress model, dependent on an unchanging set of cognitive problems, was the zeitgeist for many years. When scientists tried to develop treatments to combat the thinking skills problems, they aimed to show they couldn’t be. This sets up an interesting issue – usually most negative studies are not published in the scientific literature, but in this field, they are all available.
This theory was also bolstered by data showing that the larger the cognitive difficulty, the worse the outcome (3) and that they were also linked to the costs of care (4). So, at this point you would think that it was important to try to improve thinking skills because the treatment would not only benefit recovery, but it might also reduce the costs of care.
Looking closely at studies on potential thinking skills treatments, you find that in one or two, there was a glimmer of benefit. If you supported someone to use strategies to remember things, they remembered much more, sometimes no differently than people without memory problems. This support also worked even if the person was unaware that they were using a strategy or that they even had to remember the list. These studies were the kernel of developing the treatment we now know as cognitive remediation. It has been developed over a long period of time, and we now have a treatment that we know is effective (5) and should be available to more people.
But the question is, why did we not hit on this treatment sooner? What held us up when we knew that cognitive difficulties were problems and that they were experienced by people before, during, and after their first episode and continued between symptom episodes. Firstly, this tale of stepping up the garden path was because most research concentrated on reducing symptoms – which is an important area of research, but it shouldn’t be the only one. Second, psychological treatments are hard to develop when research is concentrated on drug therapies. Again, we need research into drugs that help people with psychosis cope and provide recovery benefits. Finally, this is number three, we, the scientists, didn’t test rigorously enough. Our null hypothesis was that we were going to fail, so we probably gave up much too easily. Let’s not do that again.
(1) Chapman & Chapman (1973) Disordered thought in schizophrenia, Appleton-Century-Croft
(2) Nuechterlein & Dawson (1984) A heuristic vulnerability/stress model of schizophrenic episodes. Schizophrenia Bulletin, 300-12.
(3) Wykes & Dunn G (1992) Cognitive deficit and the prediction of rehabilitation success in a chronic psychiatric group. Psychological Medicine, 22, 389–398.
(4) Patel et al (2006) Schizophrenia Patients with Cognitive Deficits: Factors Associated with Costs, Schizophrenia Bulletin, 32, 776–785
(5) Vita et al (2021) Effectiveness, Core Elements, and Moderators of Response of Cognitive Remediation for Schizophrenia. JAMA Psychiatry, 848-858.