Frontal D2/3 Receptor Availability in Schizophrenia Patients Before and After Their First Antipsychotic Treatment: Relation to Cognitive Functions and Psychopathology

BACKGROUND

We have previously reported associations between frontal D2/3 receptor binding potential positive symptoms and cognitive deficits in antipsychotic-naïve schizophrenia patients. Here, we examined the effect of dopamine D2/3 receptor blockade on cognition. Additionally, we explored the relation between frontal D2/3 receptor availability and treatment effect on positive symptoms.

METHODS

Twenty-five antipsychotic-naïve first-episode schizophrenia patients were examined with the Positive and Negative Syndrome Scale, tested with the cognitive test battery Cambridge Neuropsychological Test Automated Battery, scanned with single-photon emission computerized tomography using the dopamine D2/3 receptor ligand [(123)I]epidepride, and scanned with MRI. After 3 months of treatment with either risperidone (n=13) or zuclopenthixol (n=9), 22 patients were reexamined.

RESULTS

Blockade of extrastriatal dopamine D2/3 receptors was correlated with decreased attentional focus (r = -0.615, P=.003) and planning time (r = -0.436, P=.048). Moreover, baseline frontal dopamine D2/3 binding potential and positive symptom reduction correlated positively (D2/3 receptor binding potential left frontal cortex rho = 0.56, P=.003; D2/3 receptor binding potential right frontal cortex rho = 0.48, P=.016).

CONCLUSIONS

Our data support the hypothesis of a negative influence of D2/3 receptor blockade on specific cognitive functions in schizophrenia. This is highly clinically relevant given the well-established association between severity of cognitive disturbances and a poor functional outcome in schizophrenia. Additionally, the findings support associations between frontal D2/3 receptor binding potential at baseline and the effect of antipsychotic treatment on positive symptoms.

Well-being and depression in individuals with subclinical hypothyroidism and thyroid autoimmunity - a general population study

BACKGROUND

The association between subclinical hypothyroidism (SCH), with and without raised thyroid peroxidase antibodies (anti-TPO), and well-being or depression is still controversial, in spite of many studies on the topic.

AIMS

In this large general population study of 8214 individuals, we aim to clarify the significance of elevated levels of anti-TPO as a marker of poor well-being and depression in euthyroid individuals and individuals with SCH.

METHODS

In participants from the Danish General Suburban Population Study (GESUS), serum thyroid stimulating hormone (TSH), total triiodothyronine (tT3), free thyroxine (fT4) and anti-TPO was measured. Prevalence of poor well-being and depression was measured using the WHO-5 Well-being questionnaire and WHO MDI [Major (ICD-10) Depression Inventory] questionnaire.

RESULTS

Raw score for well-being or depression overall and stratified for sex was not more significantly different in euthyroid individuals than in individuals with SCH, with or without high anti-TPO, except that euthyroid women with elevated anti-TPO had better well-being (P = 0.03) compared with euthyroid women with anti-TPO within the reference range.

CONCLUSION

Elevated anti-TPO levels cannot be used as a general marker of poor well-being or depression in the general population.