Table 4. Regression analysis of development and regulatory review times for psychotropic drugs approved in the United States, 1963-1997.

Dependent

Variable

NDA Phase

IND Phase

Synthesis-to-Approval Phase

Coefficient

(t-statistic)

P-Value

Coefficient

(t-statistic)

P-Value

Coefficient

(t-statistic)

P-Value

CONSTANT

42.91

(2.85)

<.0001

-3312.79

(398.39)

<.0001

-5739.93

(611.71)

<.0001

YEAR

1.71

(0.20)

<.0001

2.98

(.31)

<.0001

Y9497

-12.57

(2.05)

<.0001

RATING

-7.63

(1.64)

<.0.001

12.04

(3.92)

.0023

12.82

(6.43)

.0471

ANINF

-15.89

(3.29)

<.0001

-35.77

(7.79)

<.0001

-38.46

(11.44)

.0009

ANALG/

ANEST

-9.28

(3.59)

.0099

-12.83

(8.45)

.1297

-13.51

(12.25)

.2708

ANTINEO

-10.89

(3.93)

.0058

-3.93

(9.25)

.6711

10.11

(14.54)

.4873

CARDIO

-5.25

(3.36)

.1184

-17.44

(7.96)

.0289

-9.58

(11.83)

.4186

ENDO

-9.07

(4.15)

.0290

-11.34

(10.01)

.2577

-3.94

(15.30)

.7969

-12.19

(5.36)

.0233

-32.08

(12.56)

.0109

-51.50

(21.13)

.0153

MISC

-8.38

(4.47)

.0612

-21.57

(11.19)

.0544

23.31

(18.84)

.2168

OCNS

-8.25

(4.30)

.0558

-22.72

(10.25)

.0271

-12.65

(15.69)

.4206

RESP

5.54

(4.83)

.2525

-19.75

(11.50)

.0863

2.17

(17.03)

.8986

R²

.1491

.168

.252

9.88

10.14

11.64

N

631

564

391

The IND phase is the time from IND filing to NDA submission. The NDA phase is the time from NDA submission to

NDA approval. The synthesis-to-approval phase is the time from synthesis of the compound to U.S. marketing approval.

Standard errors are in parentheses.

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