Study One of this research aimed to assess interpersonal problem-solving ability in individuals who evidenced suicidal behaviour. Suicide attempters were compared with mixed psychiatric outpatients and normal controls on a measure of means-ends problem-solving. The results of Study One suggested that suicidal individuals produced significantly fewer relevant means, story directed responses and sufficient narratives compared to both normal and psychiatric subjects. On qualitative indices of introspection, emotional relevant means and on time and obstacle recognition suicidals were significantly more deficient than control groups. Amongst suicidal subjects greater social dysfunction, stress and affective disturbance was associated with poorer interpersonal problem-solving. A model for the development of suicidal behaviour which suggested possible points of entry for intervention was proposed. In Study Two three treatment strategies for suicidal behaviour - Cognitive Therapy, Problem-solving Training and Psychiatric After Care were compared. In general the results suggested that all treatments were having some positive effects. The most significant changes in problem-solving skills occurred in the group receiving such training but improvement in this area was also noted in the Cognitive Therapy Group. It was proposed that aspects of Cognitive Therapy may have direct influence on problem-solving behaviour. Affective change seen at the end of eight weeks of treatment followed a different time course compared to cognitive change and the maintenance of such change to follow-up was shown to be dependent upon skills learnt during Cognitive Therapy and Problem-solving Training. Problem-solving Training had the most significant impact in improving social dysfunction and all treatments were shown to reduce suicidal ideation but at differing rates. One episode of suicide attempt occurred in the Psychiatric After Care Group representing a 6.25 percent rate of reoccurrence. It was concluded that the acquisition of interpersonal and cognitive skills held implications for the prophylaxis of suicidal behaviour. Suggestions for early primary intervention within the family and education systems were proposed.