Distressing condition initially explored by northern writer (5)
I believe the answer is:
ibsen
'writer' is the definition.
(dramatist Henrik Ibsen)
'distressing condition initially explored by northern' is the wordplay.
'distressing condition' becomes 'IBS' (irritable bowel syndrome).
'initially' indicates taking the first letters.
'by' means one lot of letters go next to another.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
The initial letter of 'explored' is 'e'.
'ibs'+'e'+'n'='IBSEN'
(Other definitions for ibsen that I've seen before include ""Doll's House" dramatist" , "not one for 'All work and no play ...'" , "Norwegian dramatist of 'Hedda Gabler'" , "Henrik -, dramatist from fourteen down (Hedda Gabler)" , "foreign author" .)