Comparison of first episode depresssion and recurrent depresssion in terms of sociodemographic, clinical and neuropsychological variables

Major depresssion is one of the most frequent psychiatric disorders. It can cause serious disability due to high risk of chronicity and recurrence. Neurocognitive dysfunction seen in major depression is one of the most important causes of disability and it is being recognized more and more each day.Due to developments in neuroimaging it is discovered that several brain areas are affected in depression. Neurocognitive testing methods used to evaluate the function of these areas showed that cognitive functions related to these areas are affected in depression. But the findings are controversial and it is not known whether this controversy is due to the heterogenous nature of depression or due to any different underlying mechanism of depression.Although there are many studies in the literature about the factors underlying recurrence, the heterogenous nature of depression makes it difficult to precisely discriminate the risk factors of recurrence in depression. Because of this, in this study it is aimed to investigate the effect of several factors on risk of recurrence and to find out if there is a sociodemographic, clinical and neurocognitive difference between first episode depression and recurrent depression.As a result of this comparison it was found out that first episode patients had a higher age of onset than recurrent depression group. There were more female patients in both groups but this sex difference disappeared as depression became recurrent. There was a small number of males in the study group and it was seen that male patients in overall was more melancoholic than female patients and this was interpreted as a probable way of male patients to seek for help only in severe cases like melanchololic depression.As for the neurocognitive functions, although recurrent group was expected to have a worse performance, it was found out that recurrent group had a better performance than the first epsode group especially in verbal fluency subtest (total KAS score) and Boston naming test (total number of spontenously named items and total number of named items). In regression analysis this difference was found out to be predicted by especially the high education level of the recurrent depression group.It was also found that the scores of fruit-name and animal name counting subtest of verbal fluency, the learning score of verbal memory test and the total score of Benton facial recognition test showed a decrease as age increased while Stroop reading time of the colour of colored words and Stroop time difference shoed an increase as age increased. These data showed that the executive functions, attention and learning is negatively affected from age.When the groups were evaluated according to sex, it was seen that in the first attackgroup female patients showed a better performance in Benton face recognition test, in the recurrent group they showed a better performance in Boston naming test and in the whole group they were better in terms of Boston naming test, verbal fluency fruit naming subtest and in learning score of verbal memory test compared to male patients. In regression analysis Boston naming test score was best predicted by female sex and education. But it is difficult to interpret this sex difference since there could be other unevaluated variables associated with sex. So, matching according to sex seems important in neuropsychological testing.It was also found that Boston naming test score, immediate memory score of the verbal memory test and Stroop reading time of the colour of the words were affected negatively from depression severity as measured by Hamiton depression rating scale indicating that naming ability, simple attention, sustained attention and executive functions were adversely affected from depression severity. Also, it was seen that the perseveration scores of animal counting subtest of verbal fluency tended to show an increase as the total time of depression increased indicating that the executive functions could get worse as exposure to depressive period increases. When the recurrent depression group was divided into two subgropus according to the number of depressive attacks, no neurocognitive difference could be found between the groups of 3 or more depressive attacks and less than 3 depressive attacks.As a result, in this study it was seen that depression severity affected especially the neuropsychological tests related to naming, attention and executive functions all associated with prefrontal lobe and that it was seen that this prefrontal dsyfunciton tended to show an increase as time with depression increased. But since no matching could be made according to age, sex and level of education which were shown to significantly affect the neurocognitive function, it could not be possible to precisely discriminate the probable variables specific to depression. So, in the future, studies should be designed controlling for these factors in order to discriminate variables specific to the nature and type of depression and longitidunal studies should be planned to see if neurocognitive dysfunction resolves with the recovery of depression or not.