Different olfactory perception in heroin addicts: an fMRI study

Background: Addiction as a mental disorder has large adverse effects on brain health. It alters brain structure and deteriorates brain functionality. Impairment of brain cognition in drug addiction is illustrated in many previous works; however, olfactory perception in addiction and in particular the neuronal mechanisms of it are rarely studied. Methods: In this experiment, we recruited 20 heroin addicts and 20 normal controls of the same sex, age, handedness, and socioeconomic status, and compared their brain function while perceiving non-craving odors during the fMRI scanning. Our aim in choosing this task is to define the default olfactory system performance in addicts compared to healthy people. Results: Our study showed an overall larger activation in addicts when processing olfactory stimuli; in particular and when comparing the two groups, the right anterior cingulate and right superior frontal gyrus had higher activations in normal, whereas left lingual gyrus and left cerebellum showed stronger activations in addicts group. Conclusion: The result of this study can unveil the missing components in addiction brain circuitry then are helpful in better understanding the neural mechanisms of addiction, and maybe advantageous in designing programs for addiction prevention or clinical treatment.