With ongoing research, psychiatric professionals continue to develop a better understanding of the roles of biologic, psychosocial, and sociocultural factors in the development of psychopathology. It has become increasingly apparent that explanations based on only one of these factors are likely to be incomplete. Today, the field supports the belief that an interaction of several causal factors produces disorders.

One framework providing a useful heuristic for an integrative approach to psychopathology was developed by Dante Cicchetti and his colleagues. This framework incorporates several different theories and perspectives into an all-inclusive conceptual framework known as the developmental ecological perspective (DEP). This perspective is useful for conceptualizing the influences of risk and protective factors on a person’s development. It simultaneously addresses individual and environmental characteristics, emphasizing the interactive and reciprocal influences of the person, family, culture, and community. It is integrative, including the broader contexts of development and functioning. Additionally, it is informed by the genetic and neurophysiological ontogenic variables that each individual possesses. Underscoring the idea that the child’s context affects his or her development, this perspective posits that contextual characteristics and events may enhance or impede a person’s development and contribute to his or her adaptation or the emergence of psychopathology.

While developed originally to explain maladaptation in children, the DEP is equally valid in its application to adults. Cicchetti’s perspective evolved from the work of ecology theorist Uri Bronfenbrenner, although it does not precisely reflect every aspect of Bronfenbrenner’s ideas. Brofenbrenner asserted that people’s contexts are crucial to understanding their development and behaviors. Cicchetti’s ideas also evolved from the work of various developmental theorists who wrote that, during the course of their development, human beings must achieve critical competencies (such as attachment or the development of prosocial behaviors) to successfully meet the challenges of later developmental stages. Research has shown that children who do not master competency-specific tasks (e.g., prosocial behavior) are at increased risk for later social maladjustment.

The DEP draws on and integrates a number of ecological and transactional models to explain how risk and protective factors at multiple levels of an individual’s ecology and prior development contribute to our understanding of the developmental consequences of exposure to certain environmental toxins and the processes that underlie maladaptive and resilient outcomes. In this conceptualization, risk and protective factors can be present at all system levels of the person’s ecology. Four distinct system levels describe influences operating in the person’s environment. The two most distal levels of the environment are the macrosystem, which includes the beliefs and values of the culture, and the exosystem, which includes aspects of the community in which the individual and family lives.

The more proximal levels of the environment are the microsystem and ontogenic development, and these systems exert the most direct influences on development. The microsystem includes the immediate settings in which the individual exists, most notably the family home and school. Ontogenic development consists of individual characteristics connected to the person’s own development and adaptation. This developmental ecological framework addresses both individual and environmental characteristics, simultaneously emphasizing the interactive and reciprocal influences of the individuals, their family, the community, and the greater sociocultural arena in which they develop and live. It includes the broader contexts of development and functioning, and it is solidly informed by the genetic and neurophysiologic variables inherent within each unique human being (see Chapter 5).

People and their behavior must be understood in a developmental context. When working with an individual, providers should have an awareness of the point where the person is at in his or her developmental trajectory and what influences are affecting that development. Understanding development is crucial for practitioners in that the life histories of patients demand developmental formulations to achieve a sense of understanding of the origins of the presenting symptoms and disturbing behaviors that bring the patients to psychiatric treatment.

There are many theories of human development, and new ones are emerging constantly, questioning and building on earlier discoveries. There are two classical approaches to the study of human development: the stage model and the longitudinal lines of development model. Each has distinct advantages and disadvantages. The more traditional approach is to examine each stage of development, reviewing how each capability or domain of functioning is unfolding chronologically. An alternative strategy used to teach development is to choose a particular aspect of human development and track it from birth until death. This is a helpful strategy for understanding the process of development and is useful for researchers who are searching for the antecedents of characteristics that occur during later developmental periods. Thinking about development as a series of stages, albeit a conceptually simplistic approach to the complex evolution of the human condition, nevertheless is a useful heuristic for clinicians. It also reflects how practice has unfolded traditionally, with practitioners focusing on specific areas of specialization and interest: pediatric, young adult, and older adult.

There are several domains of human development in which clinicians should be thoroughly grounded in order to understand deviations from “normal” development and the effects of risk/protective factors on these domains. These include biological considerations (including genetic, neurological, and endocronological), and cognitive, emotional, social, and moral development.

3.4.1 The Role of Genes and Environment in Development

The genes a person possesses contain all of the information required to define the individual. The development of the nervous system depends on environmental as well as genetic factors. At each level and stage of development, the microenvironments and macroenvironments of the human organism play a critical role. But unfolding the genetic program with complex sequences and patterns of expression makes it difficult to separate out the relative contribution of genetic and epigenetic influences. Genes influence the environment through the production of proteins, and the environment, in turn, alters the expression of genes. This reciprocal relationship is played out over the entire course of development.

3.4.2 The Role of Genes and Environment in Psychopathology

Genes do not encode mental illnesses, nor behavior. Genes encode proteins, and in psychopathology and the development of mental illnesses individual genes code for a subtle molecular abnormality caused by a genetically altered protein. This could include proteins that regulate neurodevelopment (neuronal migration, selection, differentiation, or synaptogenesis). It could also include proteins ranging from enzymes to transporters, signal transduction molecules, synaptic plasticity factors and many more.

Current thinking about the pathway from gene to mental illness asserts that mental illnesses are not caused by a single gene, nor a single subtle genetic abnormality, but by multiple small contributions from several genes, all interacting with environmental stressors.