SSRI Medications and Problem solving
Memory impairments are connected to fluid inteligence... read this:
http://www.ncbi.nlm.nih.gov/pubmed/16206235

Also consider that stress and ageing decrease fluid inteligence. In addition you said that you care less to solve... it is motivational not cognitive problem.

for real conclusion try to find if you did take any inteligence test (with norms) and try to visit clinical psychologist to compare your new result to old result.

Result from clinical psychologist is most important because maybe you have only impression.