Attachment theory proposes that psychological functioning and affect regulations are influenced by the attachment we form with others. Early relationships with parents or caregivers lay the foundations for attachment styles. These styles are proposed to influence how we relate to others during our life can be modified by the relationships and events we experience in our lifespan. A secure attachment style is associated with a capacity to manage distress, comfort with autonomy and the ability to form relationships with others, whereas insecure attachment can lead to dysfunctional relationships, emotional and behaviour avoidance. Attachment theory provides a useful framework to inform our understanding of relationship difficulties in people with psychosis. This paper aims to complement recent systematic reviews by providing an overview of attachment theory, its application to psychosis, including an understanding of measurement issues and the clinical implications offered.

A narrative review was completed of the measures of attachment and parental bonding in psychosis. Its clinical implications are also discussed. The paper also explores the link between insecure attachment styles and illness course, social functioning and symptomatology. The following questions are addressed: What are the key attachment measures that have been used within the attachment and psychosis literature? What are the results of studies that have measured attachment or parental bonding in psychosis and what clinical implications can we derive from it? What are some of the key questions for future research from these findings in relation to the onset of psychosis research field?

The most commonly used measures of attachment in psychosis research are reviewed. Self-report questionnaires and semi-structured interviews have mainly been used to examine attachment styles in adult samples and in recent years comprise a measure specifically developed for a psychosis group. The review suggests that insecure attachment styles are common in psychosis samples. Key relationships were observed between insecure, avoidant and anxious attachment styles and psychosis development, expression and long-term outcome.

Attachment theory can provide a useful framework to facilitate our understanding of interpersonal difficulties in psychosis that may predate its onset and impact on observed variability in outcomes, including treatment engagement. Greater attention should be given to the assessment of attachment needs and to the development of interventions that seek to compensate for these difficulties. However, further investigations are required on specifying the exact mechanisms by which specific attachment styles impact on the development of psychosis and its course.