This paper is part of long-term research into sentence complexity in academic prose written in English. It analyses 100 consecutive sentences of two texts from the area of clinical psychology published in 1907 (P19) and 2005 (P20) with the aim of understanding possible developmental trends. The analysis deals with the frequency of occurrence of different types of finite and non-finite clauses and considers the syntactic functions they perform in the sentences analysed. It also comments on the most common sentence configurations and the proportion of parataxis versus hypotaxis.