Toward personalized treatment of hallucinations

Hallucinations are common and often stressful experiences, occurring in all sensory modalities. They frequently complicate many disorders or situations, such as Parkinson's disease, schizophrenia, hearing or vision loss, intoxications and delirium. Although psychoeducation, coping techniques and psychotherapy may be broadly applicable, they do not address a specific underlying brain mechanism. Pharmacotherapy may effectively alleviate hallucinations if the corresponding mechanism is present, whereas in its absence, may only cause harmful side effects. Therefore, pharmacotherapy needs input about underlying brain mechanisms.

Recent findings suggest new underlying neurobiological mechanisms as possible therapeutic targets in selected patients, for example increased glutamate levels. In addition, neuronavigation can guide repetitive transcranial magnetic stimulation treatment of auditory verbal hallucinations to target-specific cortical regions.

We propose the use of neuroimaging methods to better understand the interaction of different mechanisms underlying hallucinations and to use this knowledge to guide pharmacotherapy or focal brain stimulation in a personalized manner. In addition, we suggest evidence from various imaging modalities should converge to answer a research question. We believe this 'convergence of evidence' avoids the problem of overreliance on single and isolated findings.