Thyroid function in clinical subtypes of major depression: an exploratory study

BMC Psychiatry

Table 3 Results of Discriminant function analysis (forward stepwise method) with diagnostic groups as the grouping variables.

Rows: Observed classifications
Columns: Predicted classifications
		Undifferentiated	Atypicals	Melancholics	Normal controls
	% Correct	p = 0.088	p = 0.111	p = 0.133	p = 0.666
Undifferentiated	62.50	5	1	1	1
Atypicals	60.00	0	6	1	3
Melancholics	58.33	0	0	7	5
Normal controls	98.33	0	0	1	59
Total	85.56	5	7	10	68
Classification Functions (coefficients)
	Undifferentiated	Atypicals	Melancholics	Normal controls
	p = 0.088	p = 0.111	p = 0.133	p = 0.666
TBII	1.04	0.57	0.49	0.14
TSH	6.78	4.03	4.47	3.87
TMA	0.01	0.01	0.00	0.00
TA	0.17	0.10	0.25	0.12
FT4	2.39	2.85	2.02	2.73
T4/T3 ratio	2.36	0.45	4.00	2.46
Constant	-39.08	-31.56	-29.45	-29.58

The analysis succeeded in a 85.56% correct classification of all cases on the basis of thyroid indices. Only one control was falsely classified. Each case is predicted to belong to the group in whose function obtains the highest value. The chance of success of this prediction depends on the group. The four groups seems to lie on a continuum with melancholics closer to controls and undifferentiated being the group more distant to controls, and atypicals in the middle.

ISSN: 1471-244X