Table 1 Some obstacles to reach (strict) causality in psychiatry

1. Classification systems are not falsifiable, because of

 (a) heterogeneity of categories

 (b) inclusion of novel factors and

 (c) publication bias

2. Brain functions are at least, in part, not-deterministic, because of

 (a) iso-energeticity and consequently

 (b) chaotic/random and stochastic processes

3. Therapies are not directed to core symptoms/characteristics, because they

 (a) do not influence subjective feelings

 (b) influence course and not pathogenesis and

 (c) are relatively ineffective

4. Markers and inquiry

 (a) do not inform on the core symptoms

 (b) but possibly on course and severity, and

 (c) inquiry is biased because of subjectivity