I have treated thousands of bipolar patients (mainly BP II) in an outpatient private practice, which is more representative of real-world practice in northern Italy (instead of the National Health Service and University centres, which people avoid for fear of stigma and to avoid mixing with psychotic individuals). As detailed in this book, most treatments shown effective in BP I have not been tested for managing BP II, and, until trials show effectiveness also in BP II, BP I guidelines cannot necessarily be adopted for BP II.

Parker's pharmacological management of BP II is at odds with all or almost all BP I guidelines, which recommend first initiating a mood-stabilising agent. Instead, Parker first trials a narrow-action antidepressant, and, what is even more important, suggests trialling antidepressants long-term for mood stabilisation and to prevent recurrences. This approach is at variance with the widespread view (supported by little evidence!) that antidepressants induce cycling and switching.

In fact, Parker has been treating BP II in a way similar to my own practice for many years. Naturalistic studies have shown that antidepressants have a much lower risk of inducing switching in BP II compared with BP I (this corresponds to my clinical observations), and can prevent depression recurrences in a sub-group of BP I/BP II disorders (Benazzi, 1997; Altshuler et al., 2006; Leverich et al., 2006). Some controlled studies not designed to test this hypothesis (Amsterdam et al., 1998; Amsterdam and Garcia-Espana, 2000), naturalistic studies (Benazzi, 1997; Altshuler et al. 2006; Leverich et al., 2006), and a controlled study (Parker et al., 2006) have shown than some SSRIs can prevent depression recurrences in a BP II sub-group, without inducing cycling and switching.