We have investigated the strong correlation effects which are present in a chain model exclusively composed of hydrogen atoms, upon concerted dissociation of all of them, via different cost-effective methods based on DFT or scaled variants of MP2 theory. The presence of long-range correlation along bond breaking in an approximate exchange density functional (OPTX) is highlighted, although the corresponding decrease in energy does not suffice to completely describe the dissociation process. The influence of the scaling parameters in SCS-MP2, and related theories, is also thoroughly considered with however limited success. (C) 2011 Elsevier B. V. All rights reserved.