Uncertainties in aetiology and treatment of infantile autism--assumptions and evidence.

Uncertainty in the field of child psychiatry may at times lead to groundless assumptions about the aetiology and pathology of psychiatric disorders of childhood. Treatment based on non-validated assumptions may be ineffective and may cause more harm than good. The case is presented of infantile autism which was at first attributed by clinicians to a specific negative effect of parents on their children. Evidence grounded on research did subsequently refute the assumption implicating the parents in the aetiology of this disorder. An explanatory assumption can become evidence if it is tested and found valid. To avoid serious errors in the understanding and treatment of child psychiatric disorders, the clinician should always consider critically assumptions and opinion, provided in lieu of evidence.