Efficacy of Equine Assisted Therapy on Psychosocial Functioning, Negative Symptoms and Quality of Life in Patients With Schizophrenia: a Prospective, Randomised and Controlled Study

The clinical picture in schizophrenia involves changes in perception, cognition, and affect such as delusions, hallucinations, and disorganized thinking and disorders of attention, memory, and executive thinking. A clinical differentiation, which is widespread in practice, divides the psychopathological disorders of schizophrenic patients in the clinical core areas into positive and negative symptoms.

The term negative symptoms was introduced by Hughlings-Jackson, who made the distinction between florid-psychotic or positive symptoms and "defect" or negative symptoms. The term "positive symptoms" usually includes delusions, hallucinations and formal thinking disorders. The latter are often explained in recent research tradition as a separate "disorganization syndrome". Negative symptoms also appear in the context of other psychiatric and neurological disorders, for example in patients with depression, Parkinson's and craniocerebral traumas.

Negative symptoms, according to Frith and Done, essentially signify a "deficit of willed action" or, more generally, a pathological deficit of activity and reactivity. To establish a border between idiopathic, i.e. primarily due to schizophrenia, outlasting ("trait") negative symptoms and secondary, temporary ("state") negative symptoms Carpenter and colleagues introduced the concept of the deficit vs. non-deficit form of schizophrenia. Negative symptoms constituting the deficit syndrome include affective flattening, limited emotional range, loss of interest, speech depletion, diminished purposefulness, and social listlessness. These symptoms are considered to be primary negative symptoms if they persist beyond the onset of an acute psychotic episode and have been established by differential diagnosis that they are not or at least not entirely secondary to the presence of depression, the side effects of antipsychotic treatment or other circumstances. While primary negative symptoms are currently largely immune to any type of treatment, secondary negative symptoms may remit spontaneously or after appropriate treatment.

Men are more frequently and stronger affected by negative symptoms than women. Also, the negative symptoms manifest themselves earlier in the course of the disease and are associated with stronger cognitive impairments than in women. However, the extent of men's deficits varies little during further psychotic episodes, while women tend to have a progressive profile. Recruitment for the current study will take into account the prevalence.

The positive symptoms can be treated very effectively with medication and stabilization can usually be achieved within a few weeks. On the other hand, the negative symptoms are very difficult to influence with medication. Ideally, modern integrative psychiatric treatment concepts therefore incorporate a combination of pharmacological, psychotherapeutic and psychosocial treatment strategies adapted to the specific symptom constellation and the particular needs and deficiencies of the individual patient.