Which of the following instruments is validated for predictive screening for chronic post-traumatic stress disorder (PTSD) in those who are exposed to traumatic events?
C. Not everyone who experiences a traumatic event goes on to develop PTSD. It is difficult to predict exactly who will go on to develop PTSD. Two factors most associated with future risk of PTSD in those exposed to trauma are perceived lack of social support and peri-traumatic dissociation. The possibility of predicting PTSD has led to designing of predictive screening instruments to be used shortly after a traumatic event. The 10-item Trauma Screening Questionnaire (TSQ) is one of the best validated. The TSQ is a predictive screening instrument for victims of violent crime 1–3 weeks after the assault. In spite of high rates of sensitivity and specificity, a lower positive predictive value (around 0.48) means that although the TSQ can detect the vast majority of PTSD sufferers at 1 month, 50% of those who screened positive will not develop PTSD. Other scales listed in the question are not used directly for predicting PTSD. The Holmes and Rahe Social Adjustment Scale is used to measure the impact of life events by means of arbitrary values attached to different types of common life events. The Life Events and Difficulties scale is used to measure the contextual threat posed by life events. Appraisal of the Life Events Scale is designed to provide an index of the three primary appraisal dimensions (threat, challenge, and loss) described in Lazarus and Folkman’s transactional model of stress. The Abbreviated Injury Scale is an anatomical scoring system used to classify motor accident victims to enable emergency physical interventions.
Reference:
Reduced flush response to nicotinic acid (niacin) skin patches has been demonstrated in:
C. Niacin (nicotinic acid) is a water-soluble vitamin used as a drug for hyper-lipidaemia. It can induce a visible skin flush response that is caused by prostaglandin-mediated cutaneous vasodilatation. This normal flush response is reduced in patients with schizophrenia. The use of niacin challenge as a simple biochemical test for schizophrenia has been proposed. Depending on the criteria used, the prevalence rates of attenuated or absent response to a niacin skin patch in patients with schizophrenia ranged from 49% to 90%, compared with 8% to 23% in healthy control subjects. This abnormal flush response has also been reported in first-degree relatives of schizophrenia patients. The estimated heritability ranges from 47% to 54%. The attenuated flush response to a niacin patch seen in schizophrenia patients was not observed in patients with depression, bipolar disorder or autism. The reduced niacin flush response in patients with schizophrenia was not affected by medication status, antipsychotic drug doses, or substances such as cigarette, coffee, or alcohol consumption.
Oral administration of a tryptophan-free amino acid mixture can lead to tryptophan depletion. This can trigger relapse of depression in patients being treated for depression.
The above phenomenon is most likely seen in those on:
A. Tryptophan depletion is used as an intervention to deplete serotonin (5-HT) in humans. It is noted to reverse the antidepressant effects of SSRIs and monoamine oxidase inhibitors (MAOIs) in patients in remission with a history of depression but not in patients treated with antidepressants that promote catecholaminergic rather than serotonergic neurotransmission (such as tricyclic antidepressants, reboxetine, or buproprion). Patients who are either unmedicated and/or fully remitted are much less likely to experience relapse than patients who are recently medicated and partially remitted. Recently remitted patients who have been treated with non-pharmacological therapies such as total sleep deprivation, electroconvulsive therapy, or phototherapy and possibly CBT do not commonly show full clinical relapse with tryptophan depletion.
References:
All of the following receptor changes are correctly paired except:
B. An increased density of 5HT2 binding sites has been shown in post-mortem studies of depressed/suicidal patients. The increase in 5HT2A receptors is most prominent in the dorsolateral prefrontal cortex and in platelets of medication naïve patients. A reduction in 5HT1A receptors has also been noted in the cortex. In contrast, long-term antidepressant treatment has been shown to reduce 5HT2 receptors and increase 5HT1A function. But these changes may not be causative in antidepressant action as they pre-date any clinical response in those who have started antidepressant therapy. Of note, ECT treatment actually increases 5HT2A receptors. Most directly acting 5HT1A agonists have poor antidepressant activity. Chronic antidepressant treatment induces a reduction in β adrenoreceptor density around 2 weeks after starting antidepressants; this correlates with therapeutic effects. Unmedicated suicide victims show a greater density of β adrenoreceptors.
Which of the following is true with regard to lithium toxicity?
D. The severity of lithium toxicity has a feeble relationship, if any, with levels of serum lithium. Neurotoxicity can occur even within therapeutic levels of lithium. The symptoms of lithium toxicity can be grouped into gastrointestinal symptoms such as nausea, diarrhoea, vomiting; neurological symptoms such as severe tremors (coarse), cerebellar ataxia, slurred speech, myoclonus, and spasticity; mental symptoms such as drowsiness, disorientation, and apathy. Most patients make a full recovery when lithium is stopped but serum levels may continue to rise due to intracellular lithium release even after cessation of treatment. Rarely, persistent cerebellar damage and cognitive impairment are reported following lithium toxicity.
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