Trihexyphenidyl Misuse in Delusional Disorder

Abstract

Trihexyphenidyl is an anticholinergic medication that is routinely used for the management of extrapyramidal symptoms in patients who receive antipsychotic medications. Trihexyphenidyl has been reported to be abused by some patients, who start to take it in increasing doses and tend to report a sensation of relaxation or pleasure with this medication. Hence, whether trihexyphenidyl should be considered a psychoactive substance and whether nonprescription misuse of this medication should be considered under the purview of substance use disorders need further clarity. We present here two cases of trihexyphenidyl misuse which developed in the context of persistent delusional disorders and highlight the challenges in diagnosis in such a situation.

Misuse of Anticholinergic Medications: A Systematic Review

“…Benzhexol/Trihexyphenidyl (THP) was the most recorded abused anticholinergic drug ( Table 1 ). It has been covered by twenty-five articles, of which twelve were case reports [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], six case series [ 24 , 25 , 26 , 27 , 28 , 29 ], three observational study [ 30 , 31 , 32 ], two case control [ 5 , 33 ], one cohort study [ 34 ], and one survey [ 35 ]. Among the 12 subjects reported in the case reports, only two were female [ 21 , 22 ], while the overall age ranged from 19 [ 13 ] to 59 [ 21 ].…”

“…The route of administration was always oral, but macro dosages have been recorded [ 28 ] ( Table 1 ). With regard to the psychiatric comorbidity, schizophrenia emerged as the most recorded [ 17 , 20 , 24 , 25 , 26 , 28 , 31 , 32 ], followed by depression [ 12 , 13 , 14 , 23 , 31 ], substance use disorder [ 24 , 25 , 31 , 33 ], schizoaffective disorder [ 18 , 28 , 32 ], delusional disorder/psychotic disorder [ 21 , 22 , 29 ], antisocial personality disorder and/or conduct disorder [ 5 , 27 , 31 ], borderline personality disorder [ 24 , 31 ], adjustment disorder [ 15 , 31 ], and obsessive compulsive disorder [ 12 , 30 ]. Bipolar disorder [ 31 ], mixed personality disorder [ 24 ], anxiety [ 13 ], factitious disorder [ 32 ], schizoid disorder [ 33 ], unspecific mood disorder [ 32 ], attention deficit hyperactivity disorder (ADHD) [ 27 ], learning and intellectual disability [ 27 ], and intermittent explosive disorder [ 30 ] were reported by o...…”

“…Regarding the recorded psychiatric effects, disturbances of perception, in particular hallucinations/illusions, were the most frequently reported [ 14 , 15 , 17 , 18 , 19 , 20 , 24 , 27 , 28 , 31 , 35 ] ( Table 1 ). Eleven articles reported irritability/aggressiveness/nervousness and/or psychomotor agitation [ 12 , 15 , 16 , 22 , 25 , 27 , 28 , 29 , 32 , 34 , 35 ], and nine articles euphoria [ 12 , 13 , 17 , 18 , 20 , 24 , 28 , 34 , 35 ]. Psychosis/thought disorder was described in seven articles [ 5 , 14 , 19 , 20 , 24 , 31 , 34 ], and six articles reported a sedative/relaxing effect [ 17 , 23 , 24 , 29 , 30 , 34 ].…”

“…Eleven articles reported irritability/aggressiveness/nervousness and/or psychomotor agitation [ 12 , 15 , 16 , 22 , 25 , 27 , 28 , 29 , 32 , 34 , 35 ], and nine articles euphoria [ 12 , 13 , 17 , 18 , 20 , 24 , 28 , 34 , 35 ]. Psychosis/thought disorder was described in seven articles [ 5 , 14 , 19 , 20 , 24 , 31 , 34 ], and six articles reported a sedative/relaxing effect [ 17 , 23 , 24 , 29 , 30 , 34 ]. Disorientation/attention problems, confusion, and concentration/memory disorders were also reported by six articles [ 15 , 16 , 23 , 25 , 31 , 35 ].…”

“…Anxiety and symptoms related to mood alterations [ 5 , 15 , 20 , 22 , 24 , 35 ] have been described. Medical comorbidity was not recorded in most cases, but extrapyramidal side-effects of neuroleptics [ 25 ], cerebral palsy [ 15 ], weight loss [ 12 ], essential tremor [ 16 ], headache, and recurrent abdominal pain [ 29 ] were reported. Regarding physical symptoms asscoiated to the abuse of the drug, tachycardia [ 12 , 16 , 17 , 29 , 31 , 35 ], visual symptoms [ 12 , 13 , 15 , 25 , 31 ], dry mouth [ 15 , 20 , 23 , 35 ], headache [ 16 , 25 , 29 ], movement disorders (including dyskinesia, extrapyramidal symptoms, ataxia) [ 17 , 25 , 32 , 33 ], and gastrointestinal symptoms [ 20 , 23 , 35 ] were the most recorded ones.…”