The phenomenological diversity of auditory verbal hallucinations (AVH) is not currently accounted for by any model based around a single mechanism. This has led to the proposal that there may be distinct AVH subtypes, which each possess unique (as well as shared) underpinning mechanisms. This could have important implications both for research design and clinical interventions because different subtypes may be responsive to different types of treatment. This article explores how AVH subtypes may be identified at the levels of phenomenology, cognition, neurology, etiology, treatment response, diagnosis, and voice hearer’s own interpretations. Five subtypes are proposed; hypervigilance, autobiographical memory (subdivided into dissociative and nondissociative), inner speech (subdivided into obsessional, own thought, and novel), epileptic and deafferentation. We suggest other facets of AVH, including negative content and form (eg, commands), may be best treated as dimensional constructs that vary across subtypes. After considering the limitations and challenges of AVH subtyping, we highlight future research directions, including the need for a subtype assessment tool.
The article provides some guidelines with regard to treatment responses and therapeutic strategies:
“…patients with psychosis who fail to respond to antipsychotic medication have been found not to show increases in striatal dopamine synthesis. Similarly, levels of striatal dopamine turnover have been found to be normal in people who experienced AVH in the relative absence of delusions. This underlies the rationale of clinical practice in some countries (eg, the Netherlands) to start antipsychotics only in people with hallucinations and delusions. However, it is important to note that the reasons for the failure of pharmacotherapy may be based in individual differences in drug adherence, metabolism, or absorption and that there are often also significant differences in efficacy between and across different antipsychotics.”
“A repetitive AVH subtype may be identifiable at the treatment level, with Stephane and colleagues reporting 2 patients with repetitive and fixed content (eg, “Do it, hang yourself in the bathroom”) that did not respond to treatment with antipsychotic medications, but which decreased and stopped after treatment with fluvoxamine, a drug known to have antiobsessional effects.”