Pathways chief executive Jacqui Graham apologised for the loss of the information saying staff had visited 49 of 65 people affected by the lost documents.
She said a letter was left with each person affected, providing contact details in case they wanted to talk more or lodge a complaint.
"We take the privacy of people using our services very seriously and as soon as we were aware of the mission information, we first clarified exactly what information was in the satchel; then began talking to the people involved.''
She said most patients had been understanding, but four were ``very concerned''.
The health board declined to comment.