He was inspired by psychoanalysis, the anthropological medicine of Viktor von Weizsäcker and the existential philosophy of Martin Heidegger.
Siirala studied psychoanalysis in Zürich under the guidance of Medard Boss and Gustav Bally.
Siirala was also the founding member of Finnish Therapeia-foundation, an alternative psychoanalytic training institute established 1958.
Siirala saw human illness as meaningful reactions to the patient's life situations, both present and past.
Mentally ill people he described as placeless, meaning that they have no real place among other men, their acceptance or respect.
Handling children with problems in speech development in Medicine in Metamorphosis, Siirala's attitude comes clear.
But we must think also patients parents childhood, the phenomena of transgenerational transmission, the teachers and social workers who have ignored the problem and so on.
By that Siirala means an attitude where one's own assumptions are considered the only one, a position where things are already known - so there seems to be no real need to orient towards the subject.
Thus for Siirala 'a central feature of the delusions of the healthy seems to be the unconscious assumption that they possess reality, the criteria of what is worth notice'.
Siirala has accordingly been linked with figures like Harold Searles or Harry Stack Sullivan in his belief that the delusions of patients are 'expressions that reflect what has been dissociated, hidden, and overlooked in life'.
[5] A similar link appears in 'the psychological literature on Invisible Loyalties (Boszormenyi-Nagi & Spark 1973) and anonymous social burdens (Siirala, M.