One of the mantras of psychometrics 101 is that you cannot have validity without reliability. People expel this phrase, like others equilibrate after eating curry and nan-breads with too much gassy beer. In truth, the Platonic obsession with reliability diminishes validity. The world of science and much professional practice, remains messy, and vague until it is ‘done’. The search space for those diamonds of sense and order remains infinite.
Many years in the making, DSM-5 appeared in 2013, to a chorus of criticism; Harrington summarises this crisply (Gary Greenberg’s 2013 Book of Woe gives a painful blow-by-blow account). Harrington suggests that the proliferating symptom categories ceased to carry conviction; in the USA, the leadership of the US National Institutes of Health pivoted away from the DSM approach—“100% reliability 0% validity”, as Harrington writes—stating they would only fund projects with clearly defined biological hypotheses. The big players in the pharmaceutical industry folded their tents and withdrew from the field, turning to more tractable targets, notably cancer. For some mental health problems, psychological therapies, such as cognitive behaviour therapy (CBT), are becoming more popular, sometimes in combination with pharmacotherapy; as Harrington points out, even as far back as the 1970s, trials had shown that CBT outperformed imipramine as a treatment for depression.