Hamad v Q Catering Limited  NSWWCCPD 6 (15 March 2017)
The decision in Hamad demonstrates the importance of reviewing the available evidence in determining liability in matters involving section 11A. Particular importance should be given to a worker’s statement as to the causes of their psychological injury and the necessity to obtain expert medical evidence to comment on the whole or predominant cause.
In the present case, DP Snell noted that there was a relative paucity of medical evidence dealing specifically with what aspects of the history contributed to the worker’s psychological injury. The Deputy President also considered to what extent the arbitrator had dealt with the causation issue largely by reference to the lay evidence and his conclusions drawn from that evidence.
DP Snell concluded that there were a number of conclusions relevant to the causation issue which could not be appropriately made in the absence of medical evidence. Whilst DP Snell accepted that the arbitrator was entitled to have regard to the sequence of events and to his common knowledge and experience of ordinary life, “a series of events can have a cumulative effect, and may be causative of a psychiatric condition which does not manifest itself until a later time”.