ABSTRACT

Clinical hallucinatory experience is fortunately an uncommon event. In the context of a forensic matter, claims of hallucinatory experience are push button calls for investigative caution. A claim of hallucination signifies an experience of sensory/perception in the absence of a causative external stimulus. Hallucinations are reported as real, vivid, and sources are experienced to be located in immediate external space. Actual experience of hallucinations is a complex phenomenon. Hallucinations are possible associated symptoms with numerous disorders including chronic schizophrenia and several neurological disorders most notably epilepsy, Parkinsonism, and Lewy body dementias. Hallucinations can also be associated with substance abuse to include alcoholism and alcohol withdrawal. Apropos to forensic assessment, hallucinatory experience can be a claimed symptom in malingering syndromes. Although there are promising new developments in neural imaging technology regarding hallucinations, the mainstay evaluation technique for forensic clinicians is comparison to known baseline data. The problem is, however, that our understanding of hallucinatory experience in terms of its origin, modes of presentation, and multimodality forms has become complex and convoluted, making assessment of faked hallucinatory experience a decided challenge. Command hallucinations, which instruct commission of behavior that is unwanted or harmful to oneself or others, are rare, but understandably of particular interest to the forensic evaluator. In this chapter, we review the clinical implications of hallucination as possible symptoms of psychosis or otherwise mitigating circumstances to forensic matters. We will also review advances in emerging neuroimaging techniques that strive to definitively distinguish actual from faked hallucinatory experience. The neuroimaging findings hold promise for application when claimed hallucinatory experience is crucial in matters of forensic mitigation.