Background. Mental mechanisms have evolved to enable animals (and humans) to be able to function in various social roles. It is suggested that the nature and functions of the mental mechanisms that enable animals to act as a hostile–dominant or threatened–subordinate can be distinguished. It is further suggested these can be internally activated and ‘play off’ against each other, such that a person ‘attacks’ themselves and then responds to their own internal attacks with subordinate defences. Hence, a depressed person can submit, feel defeated, belittled, beaten down, or want to run away (escape) from their own self-attacking thoughts, while psychotic voice hearers can feel similarly to their hostile voices. Such internal interactions may relate to depression in both psychotic voice hearers and depressed people.

Method. A group of 66 voice hearers with a diagnosis of schizophrenia and 50 depressed patients were compared on a series of self-report questionnaires measuring the power of hostile self-directed thoughts/voices and the activation of defensive responses, especially fight/flight.

Results. We present evidence that schizophrenic, malevolent voice hearers and self-critical depressed people experience their hostile, internally generated voices/thoughts as powerful, dominating and controlling (i.e. have typical characteristics of a hostile dominant). Moreover, these voices/thoughts activate evolved subordinate defences such as fight/flight and these are associated with depression in both depression and schizophrenia.

Conclusion. Conceptualizing aspects of depressed and psychotic thinking as relating to evolved mental mechanisms, which are role serving, but can internally play off against each other, may open new ways of investigating certain aspects of severe pathologies.