Depression, schizophrenia, compulsion, addiction and phobia—words to strike terror in our hearts. Yet they also arouse never-ending fascination, because through studying these conditions we can gain a better understanding of ourselves as well as insight into the myriad neurophysiological processes that sustain brain activity. It is surprising, therefore, that scientific investigations of these shattering disorders of the mind have lagged behind the interest they provoke in our cultural consciousness and imagination. The optimism of the discovery of drug treatments and behaviour therapy in the mid twentieth century has long gone. Instead there is disappointment at the apparent snail's pace of new drug developments and psychological treatments. Did efforts to find effective treatments become stuck? Not so. This volume will dispel any gloom. Here we see plenty of examples of exciting new research, both in the animal laboratory and with patients in the clinic, research that is bound to push the limits of currently available treatments.
While, traditionally, pharmacological science has been kept separate from psychological science, even in uneasy competition with each other, Amy Milton and Emily Holmes have brilliantly managed to bring the two approaches together and to provide a cooperative framework. This has resulted in a collection of papers that reflect the ideas and findings from research that may otherwise not have been visible in the different worlds that the researchers represent. In a discussion meeting organized by the editors, researchers were able to learn from each other, and importantly, to ask new questions, which may well lead to new answers.
When I attended the discussion meeting, I was intrigued to find that some familiar ideas had stood the test of time. I trained as a clinical psychologist in the 1960s, and that was the time when the principles of Pavlovian fear extinction were first applied to the treatment of psychiatric patients. At that time, this form of treatment, based as it was on a mechanistic understanding of the mind, was met with incredulity and even derision. How could crude animal behaviour be relevant to the suffering of psychiatric patients? But it was. The success of the treatment was striking, especially in the case of phobias, and this eventually overcame some prevailing dogmas deeply rooted in pre-scientific thought. I find it heartening that mechanistic principles of reward learning and extinction still serve as a touchstone of translational research in contemporary theories.
I was struck by recent developments in therapeutic approaches to anxiety disorders, which have challenged received scientific opinion. One such development is the theory and practice of ‘erasing’ emotionally damaging memories via reconsolidation. To me it still is a revelation that it is possible to transform vivid memories of personally terrifying experiences and even to prevent them from settling in long-term memory in the first place. This approach has opened up exciting possibilities of preventing the harm sustained by victims of traumatic stress, which was once considered irreversible.
The treatment of mood disorders too has forged ahead in new directions. This was facilitated through a more precise operational definition of affective bias, such as anhedonia, a necessary step for conducting relevant research with animals, such as rats and mice, which must be far removed from having human-type subjective experiences. This new work paves the way for more targeted pharmacological and psychological interventions. Both approaches work in harmony and will therefore bury the antagonism between the old dualistic stance of brain versus mind, and biology versus psychology. Thankfully, we now can take for granted that the search for neurophysiological mechanisms in the brain will not diminish our understanding of our own subjective experience, nor of the experience of patients suffering from mental disorders.
Tremendous progress has been made in the understanding of addiction over the last few decades. Again this has been facilitated through painstaking studies of the behaviour of rodents and the underlying neurochemistry in the brain. One striking breakthrough has been the insight that different brain systems underlie wanting and liking. In other words, the craving for a drug and the pleasure in its effects are very different things. This distinction has changed the understanding of the nature of addiction. It is also of high relevance to obsessive–compulsive disorders. How to extinguish an unwanted craving or compulsion to perform an unwanted act is still a big question, but has become a more tractable one. The new ideas on reward learning, and the hugely expanded knowledge about the effects of dopamine are sure to have a major impact in the clinic.
Not so long ago the possibility of a rodent model for schizophrenia would have been ridiculed. Schizophrenia is after all a condition that is primarily manifest in a patient's inner experience, and you learn about it mainly by what the patient tells you. However, there are tell-tale behavioural signs as well, and again these can be studied in rodents. Perhaps the major benefit of the animal laboratory is that it opens up new possibilities of finding the causes of mental illness, in the genes and in the environment. This is because only here can putative causes be experimentally manipulated. This is a complex enterprise as the causes are likely to be polygenic. Their probabilistic and sometimes subtle effects remain the big unknowns in the exploration of mental disorders. And yet their study offers a hope that is better than cure: namely prevention. This is what makes research in this area so exciting and so rewarding.
My experience of the discussion meeting was heightened by the expectation of being able to see the contributions together in a single volume—and here it is, showing the path. Uphill and stony as it may be for the researcher, the end of the path is also the end of some of the most distressing scourges of mankind.