Oxidative stress is one of the suggested mechanisms in major depression.

To determine the oxidative and antioxidative status of plasma of patients with major depression and to investigate whether there is a relationship between the potency of oxidative stress and the severity of depression.

To determine the antioxidative status of plasma, total and individual antioxidant levels which are total antioxidant potential (TAOP), total protein, albumin, uric acid, vitamin C and total bilirubin were measured. To determine the oxidative status, total peroxide level of plasma was measured in patients with drug-free depressive patients and compared with those of controls. Per cent ratio of total peroxide to TAOP was evaluated as oxidative stress index (OSI).

Plasma TAOP and individual antioxidant levels were found to be lower in patients with depression than those of controls. On the contrary, the patients had high total plasma peroxide levels. OSI values of the patients were significantly higher than those of controls (P = 0.002), and a significant positive correlation between Hamilton Depression Rating Scale (HDRS) and OSI values was found (r = 0.54, P = 0.01).

The patients with major depression are exposed to oxidative stress, and OSI may be useful to reflect the severity of the disease.

Alcohol dependence is a psychiatric disorder associated with an increased risk of suicidal behaviour. This is also associated with an increased number of suicide risk factors.

The current study examined the sociodemographic and clinical characteristics of a number of alcohol-dependent patients who attempted suicide.

We studied a consecutive series of 377 alcohol-dependent patients in our in-patient clinics. Their alcohol-use histories were assessed through semistructured interviews. The Suicidal Behaviors Questionnaire, the Childhood Trauma Questionnaire, the Michigan Alcoholism Screening Test and the Hamilton Depression Rating Scale were administered to all patients. Serum total cholesterol levels, mean corpuscular volume, the liver enzymes gamma glutamyl transferase, aspartate aminotransferase and alanine aminotransferase were routinely measured. In the statistical analyses, Student's t-test and chi-squared tests were applied.

Of the 377 alcohol-dependent patients, 89 (23.6%) had histories of attempted suicide. Thirty-four (42.5%) of the 80 female alcohol-dependent patients and 55 (18.5%) of the 297 male alcohol-dependent patients had attempted suicide; this gender difference was statistically significant (χ2 = 27.7, P < 0.001). A greater proportion of the suicide attempters than of the non-attempters met the Diagnostic Statistical Manual IV criteria for another psychiatric disorder (60.6%, n = 54, vs. 40.6%, n = 117; χ2 = 14.8; df = 6; P < 0.05). The difference of total cholesterol levels between female (mean = 144.0, SD = 58.3; mean = 158.0, SD = 83.9; t = 4.5; P < 0.05) and male (mean = 133.7, SD = 50.5; mean = 163.6, SD = 69.7; t = 11.7; P < 0.01) attempters and non-attempters was statistically significant.

These results suggest that suicide attempts in alcohol-dependent patients are associated with more profound biopsychosocial pathology and decreased serum cholesterol levels.

A view that handedness is not a dichotomous, i.e. left–right, phenomenon is shared by majority of researchers. However, there are different opinions about the exact number of hand-preference categories and criteria that should be used for their classification.

This study examined hand-preference categories using the latent class analysis (LCA) and validated them against two external criteria (i.e. hand demonstration test and a series of arbitrary cut-off points).

The Edinburgh Handedness Inventory was applied to 354 individuals randomly selected from the general population, and the obtained data were analysed using the LatentGOLD software.

Three discrete hand-preference clusters were identified, i.e. left-, right- and mixed-handed category. Further subdivision of hand-preference clusters resulted in a non-parsimonious subcategorization of individuals. There was a good agreement between the LCA-based classification and classification based on hand-preference demonstration tests. The highest agreement between the LCA model and the different types of arbitrary classification criteria ranged between 0 ± 50 and 0 ± 70 of the laterality quotient.

The study findings supported the view that handedness is not a bimodal phenomenon. However, definitions and subcategorizations of mixed-handedness using the cut-off points that are outside of the recommended range may lead to misclassification of cases. It is hoped that the categorization and validation of handedness developed in the context of this study will make future research in this area less dependent on arbitrary values and criteria.