Harm Avoidance is Correlated with the Reward System in Adult Patients with Attention Deficit Hyperactivity Disorder: A Functional Magnetic Resonance Imaging Study

Objective@#Hypoactivity in the reward system among patients with attention deficit hyperactivity disorder (ADHD) is a well-known phenomenon. Whether the activity in the reward pathway is related to harm avoidance, such as in sensitivity to punishment, is unclear. Evidence regarding the potential difference between ADHD patients and controls in terms of this association is scarce. @*Methods@#Event-related functional magnetic resonance imaging was conducted on subjects performing the Iowa gambling test. Fourteen adults with ADHD and 14 controls were enrolled in the study. @*Results@#Harm avoidance was found to be positively correlated with the activities of the bilateral orbitofrontal cortex and right insula in individuals with ADHD. A group difference was also confirmed. @*Conclusion@#Understanding the roles of harm avoidance and brain activation during risk tasks is important.

Positive Symptoms in Antipsychotic-naïve Schizophrenia are Associated with Increased Body Mass Index after Treatment

Objective@#Weight gain is an important risk factor for morbidity and mortality among patients with schizophrenia. We speculated that positive symptoms, related to dopaminergic hyperactivity and altered mesolimbic function, are associated with weight gain. @*Methods@#Twenty-two antipsychotic-naïve, first-episode patients with schizophrenia were enrolled. The Positive and Negative Syndrome Scale was completed at enrollment and follow-up. Body mass index (BMI) was also measured. @*Results@#The increase in BMI, after 6.04 ± 2.16 years of follow-up, was associated with positive symptoms, but not negative symptoms, before treatment with antipsychotics in antipsychotic-naïve patients with schizophrenia. @*Conclusion@#This finding implied that dopaminergic hyperactivity could be an important factor to predict the treatment outcome. Body weight control is important for the health management of patients with schizophrenia with more severe positive symptoms.

Serotonin and Mental Disorders: A Concise Review on Molecular Neuroimaging Evidence

Serotonin is one of the most important neurotransmitters influencing mental health and, thus, is a potential target for pharmaco-logical treatments. Functional neuroimaging techniques, such as positron-emission tomography (PET) and single photon emission computed tomography (SPECT), could provide persuasive evidence for the association between mental disorders and serotonin. In this concise review, we focus on evidence of the links between serotonin and major depressive disorders, as well as other mood disorders, anxiety disorders, schizophrenia, addiction, attention deficit hyperactivity disorder (ADHD), and autism.