Stressful life events as a cause of minor affective disorder: A theoretical and empirical evaluation

Cooke, David John (1983) Stressful life events as a cause of minor affective disorder: A theoretical and empirical evaluation. PhD thesis, University of Glasgow.

Abstract

Life events have long been thought to produce psychological disturbance. Systematic attempts to define this association began in the sixties. There are considerable difficulties inherent in this task, however, certain criteria for attributing causal significance have emerged and these are examined. In the absence of experimentation, the validity of a causal proposition can be assessed in terms of four forms of validity, namely, statistical conclusion validity, internal validity, construct validity and external validity. Each form of validity is described and the life event literature is reviewed in relation to it. Certain principles of design and analysis, which would enhance the validity of any putative causal association, are presented. This discussion of validity is followed by an analysis of the importance that additional variables have in respect to the simple link between life events and psychological disturbance. The range of variables, which have been implicated, is outlined. Theoretical and empirical advantages which may be derived from the consideration of, additional variables are discussed. Four hypotheses regarding the influence of additional variables are put forward and their implications described. The empirical evidence in support of each of these hypotheses is critically reviewed. The work of George Brown and his colleagues is considered in detail. The methodological and statistical difficulties inherent in corroborating these hypotheses is discussed. A mathematical model designed to aid the evaluation of each of these four hypotheses is described. The Study: The study has the general aim of applying the principles of design and analysis, which are discussed in the review, to the clarification of the relationships among life events, minor affective symptoms and additional variables. Four clusters of symptoms emerge. These are interpreted and called 'anxiety-depression', 'cognitive-depression', 'vegetative-depression' and 'endogenous-depression'. The reliability of life event ratings is assessed using inter-rater procedures and the Kappa coefficient. The quantitative but not the qualitative ratings, achieve acceptable levels of reliability. A weighted index of the degree of life stress experienced by the respondents called total life stress (T.L.S.) is derived and its association with each of the four syndromes is calculated. A significant association is found between T.L.S. and 'anxiety-depression' in the total sample and the female sub-sample. No other significant associations are detected. The relationships between six types of life events and each of the symptom clusters are examined. Undesirable life events correlate with 'anxiety-depression' alone. Entrance life events display a counterintuitive relationship with 'endogenous-depression' in the male subsample. No other significant associations are detected. Idiographically sensitive measures do not dramatically improve the prediction of 'anxiety-depression'. The influence which demographic and personality variables have on the simple association between T.L.S, and 'anxiety-depression' is calculated. Respondents' sex has a synergistic influence. Age and Neuroticism predict 'anxiety-depression' in their own right. The influence that seven measures, conceptually derived from the vulnerability factors of Brown and his colleagues, have on the simple link is assessed. Only the total number of vulnerability factors and the number of confidants available influence 'anxiety-depression'. There is no evidence in support of the vulnerability hypothesis. The influence of social relationship variables is considered. The number of friends, the number of social interactions and the extent of confiding in relatives contribute to the prediction of 'anxiety- depression' in the total sample and the female sub-sample. Ilaa Discussion The validity of the causal proposition that total life stress produces 'anxiety-depression' is discussed in the light of the four forms of validity. It was argued that a reasonable and plausible case can be made. The influence of additional variables is considered. It is argued that they could enhance the prediction of 'anxiety-depression'. Reasons for the strong synergistic effect between T.L.S. and respondents' sex are explored. The implications that the results have for treatment or prevention were considered. The failure to replicate specific results of Brown and his colleagues is analysed. Explanations in terms of differences in the samples and measures are examined. It is concluded that the results of the study, together with the evidence from the literature review, call into question the adequacy of the vulnerability hypothesis.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: M R Bond
• Keywords: Clinical psychology
• Date of Award: 1983
• Depositing User: Enlighten Team
• Unique ID: glathesis:1983-72704
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 11 Jun 2019 11:06
• URI: https://theses.gla.ac.uk/id/eprint/72704