Trihexyphenidyl abuse in psychiatric outpatient clinic of a general hospital in Northern Nigeria

The impact of several strict anti drug laws being promulgated in several parts of the world make the citizens to look elsewhere in seeking an alternative psychoactive substance to satisfy their urge. This has led to the rise in the number of identifi able psychoactive substances. Therapeutic drugs, food items, solvents, additives or other substances that are ordinarily not previously classifi ed as psychoactive today may become one tomorrow upon recognition of their mind altering potentials. Prescription drugs and their derivatives are sometimes turned to by the substance abusers as a readily available substitute licit substance. This applies to the Over The Counter (OTC) as well as the Prescription Only Medications (POM). According to studies conducted in various parts of Nigeria, Prescription Only Medications (POM) like codeine (and other opioid analgesics), sedatives (eg rohyphnol, diazepam), barbiturates (eg phenobarbitone, amylobarbitone), steroids, amphetamine type stimulants, trihexylphenidyl (THP, exol, benzhexol, artane) are next only to marijuana among the list of commonly misused substances [1-3]. Indiscriminate use of these drugs is known to be hazardous, as they are meant to be controlled and moderately consumed under the guidance of a licensed prescriber [2]. Among patients with neuropsychiatric disorders, some of the medications that are meant for therapeutic purposes may be converted or diverted for recreational purposes. This is a common phenomenom for methadone in opiod addiction substitution therapy setting and methylphenidate in the treatment of attention defi cit hyperkinetic disorders usually in paediatric psychiatry units. Abstract

conditions or other situations, which will then nullify the need for further anticholinergic prescription [4].  [7].

Study rationale
THP abuse prevalence varies from 1.1% in the population to as high as 34% [5] in Psychiatric setting in literatures, the wide disparity in prevalence data may be due to easy accessibility of the latter group to the medication.

Magnitude of anticholinergic drug use in mental health institutions
Agboinle, et al. [11] reported the prevalence of adjunctive This is a refl ection of the commonality of adjunctive THP prescription practice among prescribers. To the best of author's knowledge, no Nigerian study had explored the extent of abuse of THP or other anticholinergics in Nigeria.

Aims
This study is intended to explore the prevalence of THP misuse and the associated factors amidst outpatients, attending psychiatric clinic of Sarkin Maska Shehu Hospital (SMASH), Funtua.

Methodology
This study was conducted in the psychiatry clinic of SMASH, Funtua. It is a secondary health care facility owned by Katsina State Government of Nigeria. The psychiatry unit of the hospital is run on all weekdays, attending to about 20-60 clients each day. Most patients that require inpatient care are referred to the state owned psychiatric hospital in the capital city of Katsina. Though fewer of such patients that are considered as low-moderate risk despite illness severity are sometimes admitted in the male, female, gynaecology, antenatal, postnatal and children ward of the hospital. Acute, short stay inpatient care and emergency room services are sometimes offered in the observation room of outpatient department clinic, accident and emergency unit to enable crisis resolution for the severely agitated patients.
Ethical approval to conduct the study was sought from Ethical Review Committee of the Katsina State Ministry of Health. Verbal informed informed consent was obtained from each participant before being recruited to partake in the study. Each participants was interviewsed with a sociodemographic questionnaire and a ten-item drug abuse screening test (DAST-10, APPENDIX).

Study participants
Consenting outpatient adult participants in the age range of 18-65 years, who have been diagnosed of Severe Mental Illness (SMI) and had been taking trihexyphenidyl (THP, benzhexol, artane, exol) within the last 12-months were considered to have met the inclusion criteria. The younger, elderly, nonconsenting and people with cognitive impairment were not recruited.

Study instruments
DAST-10 is brief screening instrument, that is useful in assessment of psychoactive substance abuse (other than alcohol and tobacco) in the past twelve months. It was adapted from the 28-item parent version (DAST-28) whose items parallel those of Michigan Alcoholism Screening Test (MAST). DAST-10 has valid psychometric properties (sensitivity, specifi city) [14] and has been used previously by other authors locally and internationally [15,16].
The word "artane" or "exol-5" is substituted for "drug" in the original instrument, while the question /item number 3 was reworded. This is to enable better understanding and ease (reverse) scoring. A score of 1 is allotted for every 'yes' answer.
Cut-off score 3 was used to determine the pattern of use/ abuse as the score of 0-2 indicates no/low risk of drug abuse, 3-5 is indicative of abuse or harmful use of drug while score of 6 and above indicate addiction/ drug dependent. This is in line with the standard scoring criteria [14] for the instrument and has also been applied in previous studies [16].
Appropriate interventional services or referral for rehabilitation were offered for individuals who met abuse criteria.

Data analysis
Collected data were tabulated and displayed in tables, then analysed with 11.65 version of Window Program for Epidemiologists (WINPEPI-11.65), using appropriate statistical tests.

Results
Data of 64 out of 70 patients recruited for the stud y were analysed, the remaining 6 were discarded due to noncompletion.

Discussion
The prevalence of THP abuse was found to be 25% in this study. This was lesser than the prevalence of 34% reported by Naja & Halaby in their comprehensive review on anticholinergic use and abuse [5]. Up to a third of attendees were also reported to be abusing various anticholinergics in other mental health settings [4]. Most THP abusers in this study were unmarried young men. Same was found in most other studies conducted in several parts of the world like Saudi Arabia and Brazil [17,18]. Amidst the sociodemographic factors, male gender is the only factor that has a signifi cant relationship with THP abuse. This follows the general trend of other psychoactive substance use which is usually more prevalent in males than female gender [19]. The Brazilian and Saudi studies also stated that other sociodemographic variables like being unemployed is common amidst THP abusers, This contrast with this study as most of the THP abusers are employed in this study probably because most of the participants engages in primary activities (like farming , manual labour} requiring physical exertion and the THP may then be used for performance enhancement.
Among clinical factors, people who reported no history of other substance use were overrepresented in the THP abusers category and this was found to be statistically signifi cant. Most THP abusers in this study reported not using other psychoactive substances. This is contrary to the fi nding of other studies that describe THP abusers as polydrug users [17,18]. possibly because lower number of participants reported history of use of other substances in this study. Another possible explanation for the contrasting fi nding is the use of a standardized drug abuse screening questionnaire for appropriate designation of Schizophrenia is the commonest axis I diagnosis among THP abusers in this study but has no signifi cant relationship with THP misuse as reported in other studies elsewhere [20].

Conclusion and recommendations
A quarter (25%) of participants in this study abuse THP. Male patients and those without history of psychoactive substance abuse are more likely to abuse THP in attendees of mental health clinic. Efforts should be geared towards preventing the surge in THP misuse in patients. It is recommended that proper attention be paid to this subgroup of individuals in prescription of anticholinergics.
Abuse potential of the THP and other anticholinergice calls for caution in its prescription amidst other disadvantages. Easy availability, affordability and indiscriminate prescription will give serendipitous patients suffi cient time to realise the euphorigenic and addictive potentials of THP [20]. Anticholinergics should be tailed off after initial prescription of about 3-months to ease gradual cessation. Alternative anticholinergic medications with lesser addictive potentials like orphenadrine (norfl ex), biperidine (akinetone) and procyclidine should be considered when available. Worthy of note is that orphenadrine is readily available in Nigeria and may be a feasible (though costlier) alternative with lesser anticholinergic, euphorigenic or addictive effects [4]. Orphenadrine is noted to have a narrower therapeutic index and this cause for caution in its prescription in suicidal patients to avert risk of overdose toxicity [21], Other medications with intrinsic anticholinergic properties (like bropheniramine, chlorpheniramine, hyoscine) can be used. Amantadine (dopamine agonist) can be used control the EPS without incurring anticholinergic effect [4]. Co-prescription of other psychotropic medications with intrinsic anticholinergic features will reduce the need for THP eg chlorpromazine, amitriptylline, olanzapine, paroxetine). For patients on typical long acting antipsychotic (LAA, depot medications), the duration of anticholinergic coverage should not exceed two weeks as the EPS from LAA usually occur within the fi rst week of injection and it is less likely after ten days of injection. . Preference should be given to atypical antipsychotics as they have lesser risk of extrapyramidal effect, while still being mindful of the possible metabolic consequences before they could ensue. Arbitrary quantity of anticholinergic prescription (eg 10 doses per month) on pro re nata (p r n) basis may be given to abort EPS in patients [4]. Reducing dosage of FGA after clinical improvement and stability may suffi ce in eliminating the EPS, effacing the need for anticholinergic medication [22].