In t h e p r e v i o u s c h a p t e r t h e r e s u l t s p r e s e n t e d t h a t s t r o n g l y s u p p o r t t h e h y p o t h e s i s o f a b n o r m a l e l e c t r o d e r m a l a c t i v i t y i n d e p r e s s i v e p a t i e n t s . However, t h e o b s e r v a t i o n t h a t o n l y some d e p r e s s e d p a t i e n t s show t h e a b n o r m a l i t y n e e d s f u r t h e r c l a r i f i c a t i o n . In v i e w o f d i a g n o s t i c and p r e d i c t i v e d i f f i c u l t i e s o f c l a s s i f i c a t i o n s y s t e m s and t h e i r r e l a t i o n s h i p t o s k i n c o n d u c t a n c e a b n o r m a l i t i e s i n d e p r e s s i o n , i t i s i m p o r t a n t t o f u r t h e r i n v e s t i g a t e t h e r e l a t i o n s h i p o f i n d i v i d u a l c l i n i c a l f e a t u r e s t o s k i n c o n d u c t a n c e a b n o r m a l i t y . Thus, i n o r d e r t o e x a m i n e t h e r e l a t i o n s h i p o f i n d i v i d u a l c l i n i c a l f e a t u r e s t o s k i n c o n d u c t a n c e a b n o r m a l i t y we need t o compare t h o s e p a t i e n t s who showed a b n o r m a l i t i e s i n t h e i r s k i n c o n d u c t a n c e in t h e p r e v i o u s s t u d y w i t h t h o s e who d i d n o t on a number o f p s y c h i a t r i c r a t i n g s c a l e s .
C u r r e n t p r a c t i c e r e l i e s h e a v i l y on n o s o l o g i e s d e v e l o p e d by t h e a n a l y s i s o f c l i n i c a l d a t a . Al thoug h t h e r e i s a d i s a g r e e m e n t a s t o
whe the r d e p r e s s i o n i s an unique e n t i t y v a r y i n g a l o ng a continuum o f s e v e r i t y o r w h e t h e r d i s c r e t e s ubg r oup s e x i s t , t h e pr ep on de ra nc e o f e v i d e n c e f a v o u r s t h e e x i s t e n c e o f a t l e a s t one w e l l - d e f i n e d syndrome, e n d o g e n o u s d e p r e s s i o n ( K e n d e l l , 1 9 7 6 ) . A l t h o u g h t h e a n a l y s i s o f c l i n i c a l d a t a has been f r u i t f u l i n h e l p i n g t o produce t y p o l o g i e s , t h e u s e f u l n e s s o f t h i s approach i s l i m i t e d and h as produced mixed r e s u l t s . F o r e x a m p l e , e n d o g e n o u s d e p r e s s i v e p a t i e n t s , a c c o r d i n g t o t h e N e w c a s t l e s c a l e ( C a r n e y e t a l . , 1 9 6 5 ) , showed lo we r e l e c t r o d e r m a l a c t i v i t y t h a n n e u r o t i c d e p r e s s i v e p a t i e n t s ( B y r n e , 1975; Noble and L a d e r , 1972; Mirkin and Coppen, 1980; Chapter 5 ) . On t h e o t h e r hand, d i f f e r e n c e s i n e l e c t r o d e r m a l a c t i v i t y between endogenous and non- e n d o g e n o u s d e p r e s s i v e p a t i e n t s a c c o r d i n g t o t h e Research D i a g n o s t i c C r i t e r i a ( RDC) ( S p i t z e r e t a l . , 1 9 7 8 ) , were n o t co n fi rm ed (Ward e t a l . , 1 9 8 3 ) . However, t h e e l e c t r o d e r m a l a c t i v i t y has r e p e a t e d l y been r e p o r t e d t o be l o we r i n t h e p r e s e n c e o f psychomotor r e t a r d a t i o n i n d e p r e s s i v e p a t i e n t s ( L a d e r and Wing, 1969; Noble and Lader, 1971; Dawson e t a l . , 1 9 7 7 ; L a p i e r r e and B u t t e r , 1980; W i l l i a m s e t a l . , 1 9 8 5 ) . A s s o c i a t i o n s f o u n d bet ween a g i t a t i o n and h i g h e l e c t r o d e r m a l a c t i v i t y (Lader and Wing, 1969) were n o t c on fi rme d in a l a t e r s t u d y (Dawson e t a l . , 1 9 7 7 ) .
F a m i l y h i s t o r y o f p s y c h i a t r i c i l l n e s s , and c o u r s e o f i l l n e s s , do n ot seem t o bea r any r e l a t i o n s h i p t o e l e c t r o d e r m a l a c t i v i t y (Lader and W in g , 1969; Ward e t a l . , 1983; T h o r r e l l e t a l . , 1 9 8 7 ) . P a t i e n t s w i t h r e c u r r e n t d e p r e s s i o n h a v e shown l o we r t o n i c e l e c t r o d e r m a l a c t i v i t y than n o n - r e c u r r e n t (Ward e t a l . , 1 9 8 3 ) . Age a t t h e f i r s t d e p r e s s i o n and d u r a t i o n o f t h e p r e s e n t o n e , up t o t h e t i me o f i n v e s t i g a t i o n , w ere n e g a t i v e l y r e l a t e d t o low s k i n c o n d u c t a n c e r e s p o n s e magnitude
w h i l e t h e number o f p r e v i o u s d e p r e s s i o n s wes n o t c o r r e l a t e d w i t h any o f t h e e l e c t r o d e r m a l v a r i a b l e s (Ward e t a l . , 1983; T h o r r e l l e t a l . , 1 9 8 7 ) . However, v er y l i t t l e i s known a bo ut t h e s i g n i f i c a n c e o f t h e s e f a c t o r s f o r t h e e l e c t r o d e r m a l a c t i v i t y in d e p r e s s i v e p a t i e n t s . On t h e w h o l e , t h e r e l a t i o n s h i p o f abnormal e l e c t r o d e r m a l a c t i v i t y t o d i a g n o s t i c symptoms o f d e p r e s s i v e p a t i e n t s i s i n s u f f i c i e n t l y known. What n o n e o f t h e p r e v i o u s s t u d i e s ta ken i n t o c o n s i d e r a t i o n i s t h e e x t e n t t o w h i c h t h e d i a g n o s t i c symptoms a r e l i k e l y t o e x p l a i n t he r e l a t i o n s h i p o f s k i n c o n d u c t a n c e t o t h e c l a s s i f i c a t i o n s y s t e m s . No s t u d y has so f a r i n v e s t i g a t e d t h e c l i n i c a l p r o f i l e s o f p a t i e n t s w it h abnormal s k i n c o n d u c t a n c e in d e p r e s s i o n . The p r e s e n t s t u d y t h e r e f o r e a imed t o i d e n t i f y t h e c l in i c a l p i c t u r e p r e s e n t in p a t i e n t s w i t h abnormal s k i n c o n d u c t a n c e in d e p r e s s i o n . METHOD D e t a i I s o f t h e s e l e c t i o n o f p a t i e n t s and t h e pr oc ed ur e o f t h e s t u d y a r e f u l l y d e s c r i b e d in t h e p r e c e d i n g c h a p t e r (Chapter 5 ) . Of t h e 61 p a t i e n t s s t u d i e d in Chapter 5» 41 (68S) were i d e n t i f i e d a s s h o w i n g a b n o r m a l e l e c t r o d e r m a l a c t i v i t y w e r e compared w i t h t h o s e p a t i e n t s who d i d no t show any a b n o r m a l i t y in t h e i r e l e c t r o d e r m a l a c t i v i t y on a number o f p s y c h i a t r i c s c a l e s . In d i f f e r e n t i a t i n g p a t i e n t s i n t o "abnormal" and "non-abnormal" g r o u p s , a c c o r d i n g to t h e r e s u l t s o f s k i n c o n d u c t a n c e , t h e "abnormal" group was d e f i n e d e i t h e r a s h a v i n g a r e s p o n s e h i g h e r o r lo wer than t h e mean s k i n c o n d u c t a n c e
r e s p o n s e s f o r t h e n o r m a l c o n t r o l s . The c l i n i c a l f e a t u r e s o f t h e abnormal and non-abnormal gro u ps a r e shown in T a b le 6 . 2 .
C l i n i c a l A ss e s s m e n t
Cl in i c a l d a t a i n c l u d e d t h e H a m i l t o n R a t i n g S c a l e ( H a m i l t o n , 1 9 6 7 ) , t h e N e w c a s t l e D i a g n o s t i c Index ( Carney e t a l . , 1 9 6 5 ) , and the PSE (Wing e t a l . , 1 9 7 4 ) . A l l o f t h e s e s c a l e a r e d e s c r i b e d f u l l y in Chapter 5 .
Fami ly H i s t o r y and Course o f I l l n e s s
In forma t i o n was c o l l e c t e d on f a m i l y h i s t o r y o f d e p r e s s i v e