Motor cortical plasticity in adolescents with early onset schizophrenia: A TMS-EMG study assessing the perturbation effect of intermittent and continuous theta burst stimulation.

BACKGROUND: Neuroplasticity in adolescents is distinct from that of adults. Literature pertaining to neuroplasticity in schizophrenia is limited to adult populations. AIM: We aimed to assess baseline (or resting) cortical excitability and cortical plasticity in adolescents with schizophrenia using the transcranial magnetic stimulation-electromyography (TMS-EMG) protocol. METHODS: Twenty adolescent cases with schizophrenia and 20 age and gender matched healthy controls were studied using a crossover design. Single pulse TMS elicited resting motor threshold (RMT) and motor evoked potentials (MEPs) were assessed. Cortical plasticity was determined by tracking MEPs after a single session continuous theta burst stimulation (cTBS) and intermittent theta burst stimulation (iTBS) up to 120 min at 12 intervals. RESULTS: Baseline (or resting) cortical excitability was found to be significantly lower in cases compared with controls. Response patterns to cTBS and iTBS were similar between the crossover. While cTBS led to inhibitory response, iTBS had an excitatory effect in both the groups. In the cases, while cTBS led to significantly greater initial inhibitory response, iTBS led to significantly lower excitatory response, compared with controls. The time taken to return to baseline excitability was significantly longer after receiving cTBS for cases, compared with controls. CONCLUSIONS: iTBS and cTBS lead to excitatory and inhibitory response, representing classical long-term depression and long-term potentiation effects, respectively, in both cases and controls. We conclude that adolescents with schizophrenia have significantly lower baseline (resting) cortical excitability as well as significantly greater inhibitory plasticity; excitatory plasticity is significantly lower.

Buprenorphine/naloxone maintenance for "poppy husk" dependence: A retrospective study.

INTRODUCTION: Despite a significant number of patients dependent on "poppy husk" in India, they are poorly characterized. Moreover, scarce data is available with respect to their treatment. METHODS: A cohort of 148 patients with "poppy husk" dependence receiving substitution treatment with buprenorphine/naloxone were followed up for 4 years, using a retrospective chart-based assessment. Baseline demographic and substance-related characteristics were described. Retention rates (operationally redefined as "6 months of uninterrupted contact anytime during their visits") over the next 4 years and their predictors were assessed. RESULTS: Mean age of onset of "poppy husk" use was found to be 27.51 years, and mean duration of dependence was 18.25 years. Mean amount of poppy husk consumed per month was 3.7 kg. Commonest reasons for initiating and quitting its use were enhancing work efficiency and lack of availability, respectively. Retention rates were 25%. Significant predictors of retention were age more than 40 years (OR = 2.295; 95%CI = 1.015-5.19) and uninterrupted treatment duration for at least 1 month from first contact (for 1 month (OR = 5.625; 95%CI = 2.28-13.89), for 3 months (OR = 10.96; 95%CI = 4.65-25.85), and for 6 months (OR = 52.8; 95%CI:14.08-197.98). DISCUSSION: Factors associated with occupation such as enhancing work efficiency and overcoming fatigue are related to use of "poppy husk." While the amount of intake is considerably large among treatment seekers who are dependent on it, their dependence duration is longer and retention rates lower than those reported for patients with prescription and injectable opioid dependence. Specific strategies to tap patients less than 40 years and to target uninterrupted contact in initial phases of maintenance should be developed.