For the 162 injured in Wednesday's subway disaster in Philadelphia, months and possibly years of post-traumatic stress disorder may follow, local experts say.

During early morning rush-hour, a subway train derailed and crashed into metal barriers, killing three and trapping many for hours. Hundreds of emergency personnel attended to at least 162 terrified passengers in the worst accident of its kind in Philadelphia in over two decades.

While clean-up and the accident's cause is assessed, many passengers could have lingering psychological effects.

"Those that let their emotions out will fare better that those who leave their emotions bottled up," said Dr. Jonathan Grindlinger, a psychiatrist working with Lock Haven Hospital.

By acting "macho" and not letting these emotions out, there is a greater risk to the mental welfare of the survivor, Grindlinger added. This is when post-traumatic stress disorder -- experienced by many Vietnam War veterans and sexual abuse victims -- surfaces.

"People who need to be in control, but can't, will have the most traumatic experience," Grindlinger said. Yet, when an individual's normal life has been put in disarray, it is next to impossible for anyone to be in control of their mental capacities, he explained.

In tragic situations like the subway catastrophe, men usually endure more mental suffering than women, because women tend to be more emotional, he said.

When disasters involve both children and adults, the adults tend to act with more responsibility, said Irving Hand, a disaster studies expert and director of the Institute for State and Regional Affairs at Penn State's Capital Campus in Harrisburg.

Hand said the survivors of the subway accident will experience feelings of guilt, but to a lesser degree than if the tragedy was on a greater scale.

Immediate reactions of disaster survivors may be that of shock or complete numbness to everything going on around them.

However, as the weeks and months go by, the survivor may experience the shocking realization of what he or she has just experienced. This delayed reaction may also include utter devastation for the survivor, Hand said.