Six serious adverse events ( acute coronary syndrome , major depression , pneumonia , suicide attempt , viral infection , and worsening of Huntington 's disease ) occurred in five participants in the PBT@ @ mg group , three ( fall with subdural haematoma , suicide attempt , and hospital admission for stabilisation of Huntington 's disease ) occurred in two participants in the PBT@ @ mg group , and one ( increasing aggression ) occurred in a participant in the placebo group .