Introduction: People seeking for psychotherapeutic help present with a variety of conditions including stress, depression, anxiety, and maladaptive individual difference factors. This paper reviews the studies investigating the link between these conditions and immunity.
Findings: The relationship between stress-related conditions and immunity varies depending on the nature of the stressor. Acute time-limited stressors are associated with an upregulation of natural immunity, brief naturalistic stressors with a shift from cellular to humoral immunity, while long-term and chronic stressors with a decrease in most functional immune measures. Depression is associated with changes in both enumerative and functional immune measures. The most consistent association is with decreased cellular immunity. There is considerable heterogeneity in study findings that may be accounted for by clinical and demographic factors. Only limited evidence has been presented for an association between anxiety and changes in immune function. The results are somewhat inconsistent and no firm conclusions can be drawn from these studies. Relatively few studies investigated the relationship between maladaptive individual difference factors and immunity. Replicated findings include an association between alexithymia and impaired cellular immunity and altered cytokine balance with a shift towards proinflammatory mediators, and a link between Type C and Type C-related coping and HIV progression and impaired immunity.
Conclusions: Several conditions leading people to psychotherapy are associated with changes in immune function. However, several findings are preliminary and demand replication. Also, most of the evidence is correlational and further studies allowing for causal inferences are needed. Future psychoimmunology studies should better clarify the clinical relevance of the findings.