Fundamentals of Psychopharmacology

Fundamentals of Psychopharmacology

L. Jarrett Barnhill, MD, DFAPA, FAAC

Before addressing the other issues in the IDD-MH Prescribers Guidelines, a basic overview of important diagnostic and treatment considerations is necessary.  There are four basic concepts, or fundamentals, for prescribers of psychotropic mediations to consider:

The prescriber requires a working knowledge of the psychopharmacological literature, especially evidenced-based/best practice parameters. These practice parameters include knowledge of:

• Basic pharmacology of medications
• Side effect profiles
• Pharmacogenetics of drug-drug interactions
• Toxicity and adverse effects and how they mimic challenging presentations or psychopathology
• Sensitivity to the consequences of long-term use

In addition to basic pharmacology, the prescriber should also be familiar with the biopsychosocial aspects of a comprehensive assessment and how to apply these findings to nonpharmacological supports and psychotherapies. Embedded in this process is the capacity to monitor treatment efficacy. There are many strategies to monitor positive and negative responses, but it is up to the treatment team to modify treatment to match the data.

Monitoring System Requirements

• Monitor new medical/neurological changes that affect behavior
• Monitor behavioral or other systems of measuring symptom response
• Review side effect profiles of all medications and how they might affect behavioral health: track dosing schedules, serum drug levels (when appropriate) and lab studies to maintain the general health of the patient
• Create timelines to track psychosocial, ecological, and medical/pharmacological data

The brain changes and adapts throughout our lifecycle. Behavior, cognition and complex brain functions are vulnerable to many physiological, genetic/metabolic, medical/neurological disorders as well as many forms of environmental toxicity. Those emerging during gestation and early childhood tend to be more severe and many are associated with severe/profound IDD. Later in life, a number of these early-onset conditions can also predispose individual vulnerability to behavioral and psychiatric disorders.

Pain, constipation, dental abnormalities and medication side effects frequently contribute to the emergence of new challenging behaviors, an escalation of long-standing challenges (baseline exaggeration), or the emergence of new challenging behaviors that are misattributed to primary psychiatric disorders. Recognizing the link and correcting the underlying conditions can help resolve these problems and diminish the likelihood of misdiagnoses and inappropriate treatments.

This should remind us that behavioral and psychiatric disorders can arise from many sources. As a result, making categorical statements about causality (genes or environment, functional or organic) are less helpful than taking a systematic view of multiple contributing factors. It is necessary to use a biopsychosocial approach that incorporates predisposing factors, precipitating events or circumstances (adverse childhood events) and perpetuating and preventative factors (resilience and strengths). This approach also helps the prescriber avoid many diagnostic and treatment pitfalls such as an overzealous reliance on psychotropic medications.

It is essential to have thorough family and medical history, physical-neurological examination, psychological evaluations, appropriate diagnostic testing, and psychiatric assessment; careful review of interpersonal, familial, cultural and other ecological factors and a re-assessment of previous diagnoses and treatment protocols.

The goal in this process is to view the individual in a larger context, and not fall into the trap of assuming that any single therapeutic intervention can resolve the issues recognized in this collaborative process. Psychotropic medications are adjunctive tools, not definitive answers. They are but one part of a larger intervention. If the decision goes forward to use psychotropics then several conditions should apply:

• Before prescribing it is the team’s responsibility to set up a program to monitor for both positive and negative treatment responses. The decisions to change medication or dosing schedules, add to or replace existing medications, and taper or discontinue ineffective medications should be data-driven and systematic.

• The process of introducing psychotropic medications involves matching existing assessment data and diagnosis, with an evidenced-based decision about specific medications.  Once the team decision is made, medications should be started at low doses and only increased when the data suggests incomplete response. The titration process should be a methodical, data-informed process designed to define the individual’s therapeutic dosages.

• A critical step in this process involves differentiating regression secondary to drug toxicity or adverse events from symptomatic worsening, emergence of a new condition, or relapse. The decision to taper or discontinue the drug should follow a reverse strategy of slow incremental reductions of 10% or so of the original dose. This is especially true for challenging behaviors that are not associated with a specific psychiatric disorder. Patience and reliance on the effectiveness of ecological interventions to stabilize regression during withdrawal are essential. 

• Some individuals with recurring mood disorders or chronic psychoses such as schizophrenia are susceptible to relapse when off psychotropic drugs. Relapse is generally a gradual process. A sudden escalation in symptoms may suggest a withdrawal phenomenon. It is useful to remember that repeated withdrawals of psychotropic medications can contribute to treatment resistance.

Assessment and treatment are cooperative ventures that culminate an extensive team effort. The collaboration draws strength from multiple professional disciplines, direct care providers, mental and medical health practitioners, and perhaps most of all, the individuals, their families, and community resources. It is essential to encourage reporting of observations, listening to these reports, and making changes when needed, as well as educating the individual, caregivers, and other team members about potential problems.