Officers are asking for public assistance in tracing 28-year-old Bathgate man Joel McDiarmid.
He was last seen by his family at his home around 4pm on Wednesday and has not been in contact since.
He is described as white, 6ft 3ins in height and of slim build with medium-length dyed blond hair.
When he was last seen he was wearing a dark green G-Star jacket, black jogging trousers and black trainers.
Sergeant Neil Traynor said: “As time passes, we are becoming increasingly concerned for Joel’s safety and wellbeing.
"He has been dealing with some anxiety issues lately and despite a number of searches and enquiries to trace him, we have not yet been able to locate him.
“He is known to travel by public transport and likes to visit Glasgow and Edinburgh.
"Anyone with any information on his whereabouts should contact us through 101 quoting reference 1809 of 18 November.”