Table 2.

The input symptoms, intermediate variables and bias variables for the diagnosis of major depressive episodes based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision

Classification of symptoms	Criterion variable	Domains in the major or minor criteria	Domain variables	Symptoms	Symptom variables	Equations to derive diagnosis or domain variables	Approximation by linear regression	Mechanisms related to introducing biases
Major depressive episode (variable= mde)						mde=mde_ma1 x mde_ma2 x (mde_mi3+ mde_mi4+ mde_mi5+mde_mi6+ mde_mi7+mde_mi8+ mde_mi9+mde_bias1) + (1- mde_ma1 x mde_ma2) x (me_ma1 x mde_ma2) x (mde_mi3+mde_mi4+ mde_mi5+mde_mi6+ mde_mi7+mde_mi8+ mde_mi9+mde_bias2)	mde=intercept + coef1 x mde_ma1+coef2 x mde_ma2+coef3 x mde_mi3+coef4 x mde_mi4+coef5 x mde_mi5+coef6 x mde_mi6+coef7 x mde_mi7+coef8 x mde_mi8+coef9 x mde_mi9+coef10 x mde_bias	Multiplication to create the situations when one or two symptoms in the major criteria confirmed and the bias (mde_bias) calculated by extracting the information of the diagnosis not explained by the input symptoms and two bias variables generated by censoring (mde_bias1 and mde_bias2) Categorising of the sum of the input symptoms in the minor criteria at the threshold of three or four (mde_bias1 and mde_bias2)
Major criteria, essential for diagnosis
		Depressed mood or a loss of interest or pleasure in daily activities for more than 2 weeks.
		Depressed mood for more than 2 weeks.	mde_ma1
		Loss of interest or pleasure in daily activities for more than 2 weeks.	mde_ma2
Minor criteria (at least 5 of the symptoms including the two in major criteria)	mde_mi
		Significant unintentional weight loss or gain	mde_mi3			mde_mi3=mde_mi3_1+ mde_mi3_2+ mde_mi3_bias		Censoring of the sum of multiple input variables
				Significant unintentional weight gain	mde_mi3_1
				Significant unintentional weight loss	mde_mi3_2
				Information of the domain not explained by the input variables	mde_mi3_bias
		Insomnia or sleeping too much	mde_mi4			mde_mi4=mde_mi4_1+ mde_mi4_2+ mde_mi4_bias		Censoring of the sum of multiple input variables
				Insomnia	mde_mi4_1
				Sleeping too much	mde_mi4_2
				Information of the domain not explained by the input variables	mde_mi4_bias
		Agitation or psychomotor retardation noticed by others	mde_mi5			mde_mi5=mde_mi5_1+ mde_mi5_2+ mde_mi5_bias		Censoring of the sum of multiple input variables
				Agitation	mde_mi5_1
				Psychomotor retardation noticed by others	mde_mi5_2
				Information of the domain not explained by the input variables	mde_mi5_bias
		Fatigue or loss of energy	mde_mi6			mde_mi6=mde_mi6_1+ mde_mi6_2+ mde_mi6_bias		Censoring of the sum of multiple input variables
				Fatigue	mde_mi6_1
				Loss of energy	mde_mi6_2
				Information of the domain not explained by the input variables	mde_mi6_bias
		Feelings of worthlessness or excessive guilt	mde_mi7			mde_mi7=mde_mi7_1+ mde_mi7_2+ mde_mi7_bias		Censoring of the sum of multiple input variables
				Feelings of worthlessness	mde_mi7_1
				Feelings of excessive guilt	mde_mi7_2
				Information of the domain not explained by the input variables	mde_mi7_bias
		Diminished ability to think or concentrate, or indecisiveness	mde_mi8			mde_mi8=mde_mi8_1+ mde_mi8_2+ mde_mi8_bias		Censoring of the sum of multiple input variables
				Diminished ability to think or concentrate	mde_mi8_1
				Indecisiveness	mde_mi8_2
				Information of the domain not explained by the input variables	mde_mi8_bias
		Recurrent thoughts of death	mde_mi9
Information due to categorisation (choosing three domains in minor criteria)	mde_bias1							Bias introduced to categorise the sum of the number of confirmed symptoms in the minor criteria
Information due to categorisation (choosing four domains in minor criteria)	mde_bias2							Bias introduced to categorise the sum of the number of confirmed symptoms in the minor criteria
Information of diagnosis not explained by the domains	mde_bias							Information of the diagnosis not explained by the input variables and two bias variables generated due to data categorisation