Depression takes many forms, and it is not always easy to diagnose. There is no doubt, however, that it represents a colossal health burden. According to the World Health Organization, it is one of the leading illnesses when ranked by impact on productivity, and directly affects 121 million people worldwide.

As has been discussed in Nature’s pages, the standard research-based model of therapy development for psychiatric disorders — target identification, drug discovery and clinical investigation — is imploding as biologists grapple with the complexities and drug companies see too few prospects to keep investing. Most psychologists agree that the drugs already in use are efficacious to a point, but with plenty of room for improving their effectiveness and reducing side effects.

Psychological treatments are the other arm of therapy for depression and many psychiatric disorders. The literature is full of trials indicating that they are in some contexts more effective and better at preventing relapse than pharmaceutical interventions. There are no physical side effects, but some of the best-validated treatments depend on therapists with training. Unlike drug therapies, there are no multibillion-dollar suppliers of these treatments with the motivation to market them and make them easily obtainable.

The money being spent on researching psychological therapies is tiny by comparison with budgets for fundamental neuroscience and for translation and drug discovery. And yet such therapies have the potential to make a substantive difference to new categories of patients. What is more, treatments could doubtless be improved in their existing applications by deeper investigation of their outcomes.

Psychological therapies have the potential to make a substantive difference to patients.

This fundamental funding imbalance is compounded by the fact that the sources of research funding disfavour studies of psychological treatments that focus only on efficacy. Nature would be the last to question the importance of research for causal or mechanistic insights. But the brain’s complexity and relative inaccessibility leaves a gulf between the current basic understanding and the observed pathologies of human minds. Taking existing psychological therapies and improving and extending their psychological models and applications, and developing new ones, regardless of the underlying neural processes in the brain, is also a justifiable endeavour for funding agencies. Given the immediate benefits this research could bring, the deficit of interest in funding it is a scandal.

Take one prominent example. Since 2006, UK governments have increasingly committed to a programme called Improving Access to Psychological Therapies. This massive, enlightened initiative in psychotherapeutic capacity-building has increased the number of practising cognitive behavioural therapists by several thousand, providing more than 600,000 people with access to these services, particularly patients with depression and anxiety disorders.

Inspect the databases of this programme and you find large variations in outcomes between UK regions. A deeper look would allow one to examine many factors relating to the effectiveness of such treatments, thereby opening the prospect of improvements in the United Kingdom and elsewhere.

As psychologists outside Britain will confirm, despite the variability in outcomes, this programme represents a world-beating standard thanks to the scale of its implementation and the validation of its treatments by the UK National Institute for Health and Clinical Excellence. And yet since its inception, the UK government has prevented any of the funds from being used for scientific research on the factors underlying its measured impacts.

This is an extreme example. Many funding agencies around the world are too keen solely to support mechanistic investigations with potential long-term payoffs, and too unwilling to appreciate that part of their portfolio should be oriented towards identifying immediately effective psychological interventions. Success in this area would further encourage policy-makers to enhance much-needed access to treatment for psychiatrically ill individuals. After all, many of these people are taxpayers who ultimately fund research into brains and minds.