Adolescent Initiation of Cannabis Use and Early-Onset Psychosis.

BACKGROUND: It is important to evaluate the impact of cannabis use on onset and course of psychotic illness, as the increasing number of novice cannabis users may translate into a greater public health burden. This study aims to examine the relationship between adolescent onset of regular marijuana use and age of onset of prodromal symptoms, or first episode psychosis, and the manifestation of psychotic symptoms in those adolescents who use cannabis regularly. METHODS: A review was conducted of the current literature for youth who initiated cannabis use prior to the age of 18 and experienced psychotic symptoms at, or prior to, the age of 25. Seventeen studies met eligibility criteria and were included in this review. RESULTS: The current weight of evidence supports the hypothesis that early initiation of cannabis use increases the risk of early onset psychotic disorder, especially for those with a preexisting vulnerability and who have greater severity of use. There is also a dose-response association between cannabis use and symptoms, such that those who use more tend to experience greater number and severity of prodromal and diagnostic psychotic symptoms. Those with early-onset psychotic disorder and comorbid cannabis use show a poorer course of illness in regards to psychotic symptoms, treatment, and functional outcomes. However, those with early initiation of cannabis use appear to show a higher level of social functioning than non-cannabis users. CONCLUSIONS: Adolescent initiation of cannabis use is associated, in a dose-dependent fashion, with emergence and severity of psychotic symptoms and functional impairment such that those who initiate use earlier and use at higher frequencies demonstrate poorer illness and treatment outcomes. These associations appear more robust for adolescents at high risk for developing a psychotic disorder.

Effects of nicotine on electroencephalography and affect in adolescent females with major depressive disorder: a pilot study.

BACKGROUND: Given that smoking is typically initiated during adolescence, and that this period in brain development seems to be uniquely sensitive to nicotine, depressed youth may be most susceptible to the neuromodulatory and mood-altering effects of nicotine. Electroencephalographic (EEG) studies suggest that individuals with major depressive disorder (MDD) exhibit left frontal lobe hypoactivation (indexed by increased EEG alpha), a region implicated in positive affect regulation, as well as right parietal hypoactivation. Smoking/nicotine abstinence has been associated with increased left frontal and right parietal alpha activity (reduced activation), which has been correlated with increased depression ratings; nicotine administration seems to normalize this depression-associated asymmetry. OBJECTIVES: This pilot study investigated whether acute nicotine administration in adolescent female smokers with MDD would alter resting EEG activity and affect. METHODS: Subjective mood ratings and EEG recordings were acquired before and 2 hours after administering a transdermal placebo or nicotine (21 mg) patch to 8 adolescent female smokers with MDD. RESULTS: Nicotine induced a modest increase in alpha1 amplitude in the right hemisphere and simultaneously decreased left-favoring alpha1 amplitude asymmetry. It also attenuated left alpha1 and alpha2 amplitude in the central region. Consistent with nicotine's stimulatory action, nicotine decreased theta amplitude in the right parietal region. No accompanying mood alterations were found, although smoking withdrawal and craving as well as physical symptom scores were reduced with nicotine. CONCLUSIONS: The results of this pilot study, the first to examine the electrocortical effects of nicotine in depressed adolescents, indicate that nicotine modulates EEG asymmetry measures, laying the stage for further research regarding the role of nicotine on affective neurocircuitry in this population.