Though many suicidal teens appear depressed or downcast, others hide their problems underneath a disguise of excess energy. If an adolescent starts displaying uncharacteristic agitation and hyperactivity, it may also signal the existence of an underlying problem. This restlessness may take the form of confrontational or aggressive behaviour.
More obvious signs that an adolescent may be suicidal include low self-esteem and self-deprecating remarks. Some teens come right out and talk or write about their suicidal thoughts - this should be taken seriously, and not ignored with the hope that it's a passing phase. Any previous attempts at suicide are loud and clear cries for help, which demand responses before it's too late.