Method for Diagnosing Depression

1 . A method for diagnosing depression comprising the steps of:

measuring expression levels of 18 genes selected from the group consisting of FASLG, CX3CR1, TBX21, ID2, SLAMF7, PRSS23, YWHAQ, TARDBP, ADRB2, PPP1R8, MMAA, SQLE, PDHA1, HAVCR2, RACGAP1, AHNAK, EDG8, and DUSP5, in peripheral blood isolated from a subject; and

determining whether or not the subject suffers from depression based on the expression levels of the 18 genes.

2 . The method according to claim 1 , comprising the step of comparing the expression levels of the 18 genes of the subject with expression levels of the genes of healthy individual, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison result.

3 . The method according to claim 1 , comprising the steps of:

obtaining an expression ratio of the expression levels of the 18 genes of the subject to expression levels of the genes of healthy individuals; and

comparing the expression ratio with predetermined data concerning expression levels of the genes of a depressed patient and of healthy individual, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison result.

4 . The method according to claim 3 , wherein the comparing step is carried out using a support vector machine.

5 . The method according to claim 1 comprising the steps of:

obtaining a mean value of the expression levels of the 18 genes of the subject; and

comparing the mean expression level with a mean expression level of the 18 genes of healthy individual, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison result.

6 . The method according to claim 5 , wherein the determining step is performed by determining that the subject has a high possibility of suffering from depression when the mean expression level of the 18 genes of the subject is significantly lower than that of the healthy individual.

7 . The method according to claim 1 , wherein the gene expression levels of the 18 genes are measured with the use of nucleic acid-immobilized solid substrates, such as a DNA chip or an array.

8 . A method for diagnosing depression comprising the steps of:

measuring expression level of at least one of 18 genes selected from the group consisting of FASLG, CX3CR1, TBX21, ID2, SLAMF7, PRSS23, YWHAQ, TARDBP, ADRB2, PPP1R8, MMAA, SQLE, PDHA1, HAVCR2, RACGAP1, AHNAK, EDG8, and DUSP5, in peripheral blood isolated from a subject; and

determining whether or not the subject suffers from depression based on the expression level.

9 . The method according to claim 8 , comprising the step of comparing the expression level of at least one of the 18 genes of the subject with a predetermined reference value, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison results.

10 . The method according to claim 8 , comprising the steps of:

obtaining a ratio of the expression level of at least one of the 18 genes of the subject to a predetermined reference value; and

comparing the ratio with a predetermined threshold value, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison results.

11 . The method according to claim 8 , comprising the steps of:

obtaining a mean value of the expression levels of at least two of the 18 genes of the subject; and

comparing the mean value with a predetermined threshold value, wherein the determining step is performed by determining whether or not the subject suffers from depression based on the comparison results.

12 . The method according to claim 11 , wherein the determining step is performed by determining that the subject has a high possibility of suffering from depression when the mean value of at least two of the 18 genes of the subject is lower than the threshold value.

13 . A program for performing the method for diagnosing depression comprising:

1) a means for inputting expression levels of 18 genes selected from the group consisting of FASLG, CX3CR1, TBX21, ID2, SLAMF7, PRSS23, YWHAQ, TARDBP, ADRB2, PPP1R8, MMAA, SQLE, PDHA1, HAVCR2, RACGAP1, AHNAK, EDG8, and DUSP5, in the peripheral blood isolated from a subject;

2) a means for storing data concerning expression levels of the 18 genes of depressed patient and of healthy individual that have been inputted in advance;

3) a means for comparing the expression levels of the 18 genes of the subject with the expression levels of the 18 genes of healthy individual;

4) a means for determining whether or not the subject suffers from depression based on the results of comparison; and

5) a means for outputting the results of determination.

14 . The program according to claim 13 , wherein in 3) above, an expression ratio of the expression levels of the 18 genes of the subject to those of healthy individual is obtained in order to compare said expression ratio with an expression ratio of expression levels of the 18 genes of depressed patient to expression levels of the 18 genes of healthy individual that have been stored in advance.

15 . The program according to claim 14 , wherein the analysis is carried out using a support vector machine.

16 . The program according to claim 13 , wherein in 3) above, the mean value of the expression levels of the 18 genes of the subject is obtained, and the mean value is compared with a mean value of expression levels of the 18 genes of healthy individual.

17 . The program according to claim 13 , further comprising a means for storing the expression levels of the 18 genes of the subject and updating the data of the depressed patient and that of healthy individual according to need.